LTC6910-3CTS8#TRPBF - ANALOG DEVICES

LTC6910-1/

LTC6910-2/LTC6910-3

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For more information www.linear.com/LTC6910

Typical applicaTion

FeaTures DescripTion

Digitally

Controlled

Programmable

Gain Amplifiers in SOT-23

The LTC

6910 family are low noise digitally program-

mable gain amplifiers (PGAs) that are easy to use and

occupy very little PC board space. The inverting gain is

adjustable using a 3-bit digital input to select gains of 0,

1, 2, 5, 10, 20, 50 and 100V/V in the LTC6910-1; 0, 1, 2,

4, 8, 16, 32 and 64V/V in the LTC6910-2; and 0, 1, 2, 3,

4, 5,6 and 7V/V in the LTC6910-3.

The LTC6910-Xs are inverting amplifiers with rail-to-rail

output. When operated with unity gain, they will also

process rail-to-rail input signals. A half-supply refer-

ence generated internally at the AGND pin supports single

power supply applications. Operating from single or split

supplies from 2.7V to 10.5V, the LTC6910-X family is

offered in an 8-lead SOT-23 package.

applicaTions

n 3-Bit Digital Gain Control in Three Gain-Code

Options

n Rail-to-Rail Input Range

n Rail-to-Rail Output Swing

n Single or Dual Supply: 2.7V to 10.5V Total

n 11MHz Gain Bandwidth Product

n Input Noise Down to 8nV/√Hz

n System Dynamic Range to 120dB

n Input Offset Voltage: 1.5mV

n 8-Pin Low Profile (1mm) SOT-23

(ThinSOT™) Package

n Data Acquisition Systems

n Dynamic Gain Changing

n Automatic Ranging Circuits

n Automatic Gain Control

Single Supply Programmable Amplifier Frequency Response (LTC6910-1)

VIN VOUT = GAIN • V

AGND

1µF OR LARGER

PIN 2 (AGND) PROVIDES BUILT-IN HALF-SUPPLY

REFERENCE WITH INTERNAL RESISTANCE OF 5k.

AGND CAN ALSO BE DRIVEN BY A SYSTEM ANALOG

GROUND REFERENCE NEAR HALF SUPPLY

6910 TA01

LTC6910-X

V+

2.7V TO 10.5V

0.1µF

G2 G1 G0

6910-1

–1

–2

–5

–10

–20

–50

–100

6910-2

–1

–2

–4

–8

–16

–32

–64

GAIN IN VOLTS/VOLT

6910-3

–1

–2

–3

–4

–5

–6

–7

DIGITAL INPUTS

FREQUENCY (Hz)

GAIN (dB)

100 10k 100k 1M

10M

6910 TA01b

–10 1k

GAIN OF 100 (DIGITAL INPUT 111)

GAIN OF 1 (DIGITAL INPUT 001)

GAIN OF 2 (DIGITAL INPUT 010)

GAIN OF 5 (DIGITAL INPUT 011)

GAIN OF 10 (DIGITAL INPUT 100)

GAIN OF 20 (DIGITAL INPUT 101)

GAIN OF 50 (DIGITAL INPUT 110)

VS = 10V, VIN = 5mVRMS

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

ThinSOT is a trademark of Analog Devices, Inc. All other trademarks are the property of their

respective owners. Protected by U.S. patents, including 6121908.

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

absoluTe MaxiMuM raTings

Total Supply Voltage (V+ to V–) ............................... 11V

Input Current ...................................................... ±25mA

Operating Temperature Range (Note 2)

LTC6910-1C, -2C, -3C ..........................–40°C to 85°C

LTC6910-1I, -2I, -3I ............................. –40°C to 85°C

LTC6910-1H, -2H, -3H ...................... –40°C to 125°C

Speciﬁed Temperature Range (Note 3)

LTC6910-1C, -2C, -3C .......................... –40°C to 85°C

LTC6910-1I, -2I, -3I ............................. –40°C to 85°C

LTC6910-1H, -2H, -3H ...................... –40°C to 125°C

Storage Temperature Range ................... –65°C to 150°C

Lead Temperature (Soldering, 10 sec) .................. 300°C

(Note 1)

pin conFiguraTion

OUT 1

AGND 2

IN 3

V– 4

8 V+

7 G2

6 G1

5 G0

TOP VIEW

TS8 PACKAGE

8-LEAD PLASTIC TSOT-23

TJMAX = 150°C, θJA = 230°C/W

orDer inForMaTion

LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE

LTC6910-1CTS8#PBF LTC6910-1CTS8#TRPBF LTB5 (6910-1) 8-Lead Plastic TSOT-23 –40°C to 85°C

LTC6910-1ITS8#PBF LTC6910-1ITS8#TRPBF LTB5 (6910-1) 8-Lead Plastic TSOT-23 –40°C to 85°C

LTC6910-1HTS8#PBF LTC6910-1HTS8#TRPBF LTB5 (6910-1) 8-Lead Plastic TSOT-23 –40°C to 125°C

LTC6910-2CTS8#PBF LTC6910-2CTS8#TRPBF LTACQ (6910-2) 8-Lead Plastic TSOT-23 –40°C to 85°C

LTC6910-2ITS8#PBF LTC6910-2ITS8#TRPBF LTACQ (6910-2) 8-Lead Plastic TSOT-23 –40°C to 85°C

LTC6910-2HTS8#PBF LTC6910-2HTS8#TRPBF LTACQ (6910-2) 8-Lead Plastic TSOT-23 –40°C to 125°C

LTC6910-3CTS8#PBF LTC6910-3CTS8#TRPBF LTACS (6910-3) 8-Lead Plastic TSOT-23 –40°C to 85°C

LTC6910-3ITS8#PBF LTC6910-3ITS8#TRPBF LTACS (6910-3) 8-Lead Plastic TSOT-23 –40°C to 85°C

LTC6910-3HTS8#PBF LTC6910-3HTS8#TRPBF LTACS (6910-3) 8-Lead Plastic TSOT-23 –40°C to 125°C

Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.

For more information on lead free part marking, go to: http://www.linear.com/leadfree/

For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/. Some packages are available in 500 unit reels through

designated sales channels with #TRMPBF suffix.

http://www.linear.com/product/LTC6910#orderinfo

LTC6910-1/

LTC6910-2/LTC6910-3

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For more information www.linear.com/LTC6910

gain seTTings anD properTies

Table1. LTC6910-1

G2 G1 G0

NOMINAL

VOLTAGE GAIN NOMINAL LINEAR INPUT RANGE (VP-P)NOMINAL

INPUT

IMPEDANCE

(kΩ)

Dual 5V

Supply

Single 5V

Supply

Single 3V

SupplyVolts/Volt (dB)

0 0 0 0 –120 10 5 3 (Open)

0 0 1 –1 0 10 5 3 10

0 1 0 –2 6 5 2.5 1.5 5

0 1 1 –5 14 2 1 0.6 2

1 0 0 –10 20 1 0.5 0.3 1

1 0 1 –20 26 0.5 0.25 0.15 1

1 1 0 –50 34 0.2 0.1 0.06 1

1 1 1 –100 40 0.1 0.05 0.03 1

Table2. LTC6910-2

G2 G1 G0

NOMINAL

VOLTAGE GAIN NOMINAL LINEAR INPUT RANGE (VP-P)NOMINAL

INPUT

IMPEDANCE

(kΩ)

Dual 5V

Supply

Single 5V

Supply

Single 3V

SupplyVolts/Volt (dB)

0 0 0 0 –120 10 5 3 (Open)

0 0 1 –1 0 10 5 3 10

0 1 0 –2 6 5 2.5 1.5 5

0 1 1 –4 12 2.5 1.25 0.75 2.5

1 0 0 –8 18.1 1.25 0.625 0.375 1.25

1 0 1 –16 24.1 0.625 0.313 0.188 1.25

1 1 0 –32 30.1 0.313 0.156 0.094 1.25

1 1 1 –64 36.1 0.156 0.078 0.047 1.25

LTC6910-1/

LTC6910-2/LTC6910-3

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For more information www.linear.com/LTC6910

gain seTTings anD properTies

Table3. LTC6910-3

G2 G1 G0

NOMINAL

VOLTAGE GAIN NOMINAL LINEAR INPUT RANGE (VP-P)NOMINAL

INPUT

IMPEDANCE

(kΩ)

Dual 5V

Supply

Single 5V

Supply

Single 3V

SupplyVolts/Volt (dB)

0 0 0 0 –120 10 5 3 (Open)

0 0 1 –1 0 10 5 3 10

0 1 0 –2 6 5 2.5 1.5 5

0 1 1 –3 9.5 3.33 1.67 1 3.3

1 0 0 –4 12 2.5 1.25 0.75 2.5

1 0 1 –5 14 2 1 0.6 2

1 1 0 –6 15.6 1.67 0.83 0.5 1.7

1 1 1 –7 16.9 1.43 0.71 0.43 1.4

LTC6910-1/

LTC6910-2/LTC6910-3

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For more information www.linear.com/LTC6910

elecTrical characTerisTics

PARAMETER CONDITIONS

C, I SUFFIXES H SUFFIX

UNIT

MIN TYP MAX MIN TYP MAX

Specifications for the LTC6910-1, LTC6910-2, LTC6910-3

Total Supply Voltage ●2.7 10.5 2.7 10.5 V

Supply Current VS = 2.7V, VIN = 1.35V

VS = 5V, VIN = 2.5V

VS = ±5V, VIN = 0V, Pins 5, 6, 7 = –5V or 5V

VS = ±5V, VIN = 0V, Pin 5 = 4.5V,

Pins 6, 7 = 0.5V (Note 4)

●

2.4

3.5

4.5

4.9

2.4

3.5

4.5

4.9

Output Voltage Swing LOW (Note 5) VS = 2.7V, RL = 10k to Mid-Supply Point

VS = 2.7V, RL = 500Ω to Mid-Supply Point

●

100

VS = 5V, RL = 10k to Mid-Supply Point

VS = 5V, RL = 500Ω to Mid-Supply Point

●

160

VS = ±5V, RL = 10k to 0V

VS = ±5V, RL = 500Ω to 0V

●

180

250

180

270

Output Voltage Swing HIGH (Note 5) VS = 2.7V, RL = 10k to Mid-Supply Point

VS = 2.7V, RL = 500Ω to Mid-Supply Point

●

VS = 5V, RL = 10k to Mid-Supply Point

VS = 5V, RL = 500Ω to Mid-Supply Point

●

150

VS = ±5V, RL = 10k to 0V

VS = ±5V, RL = 500Ω to 0V

●

180

250

180

250

Output Short-Circuit Current (Note 6) VS = 2.7V

VS = ±5V

±27

±35

±27

±35

AGND Open-Circuit Voltage VS = 5V ●2.45 2.5 2.55 2.45 2.5 2.55 V

AGND Rejection (i.e., Common Mode

Rejection or CMRR)

VS = 2.7V, VAGND = 1.1V to Upper AGND Limit

VS = ±5V, VAGND = –2.5V to 2.5V

●

Power Supply Rejection Ratio (PSRR) VS = 2.7V to ±5V ●60 80 60 80 dB

Signal Attenuation at Gain = 0 Setting Gain = 0 (Digital Inputs 000), f = 20kHz ●–122 –122 dB

Slew Rate VS = 5V, VOUT = 2.8VP-P

VS = ±5V, VOUT = 2.8VP-P

V/µs

Digital Input “High” Voltage VS = 2.7V

VS = 5V

VS = ±5V

●

2.43

4.5

2.43

4.5

Digital Input “Low” Voltage VS = 2.7V

VS = 5V

VS = ±5V

●

0.27

0.5

0.27

0.5

Digital Input Leakage Current Magnitude V– ≤ (Digital Input) ≤ V+2 2 µA

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k

to mid-supply point, unless otherwise noted.

LTC6910-1/

LTC6910-2/LTC6910-3

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For more information www.linear.com/LTC6910

elecTrical characTerisTics

PARAMETER CONDITIONS

LTC6910-1C/LTC6910-1I

LTC6910-1H

UNIT

MIN TYP MAX MIN TYP MAX

Specifications for the LTC6910-1 Only

Voltage Gain (Note 7) VS = 2.7V, Gain = 1, RL = 10k

VS = 2.7V, Gain = 1, RL = 500Ω

●

–0.05

–0.1

–0.02

0.07

0.06

–0.06

–0.12

–0.02

0.07

0.08

VS = 2.7V, Gain = 2, RL = 10k ●5.96 6.02 6.08 5.96 6.02 6.08 dB

VS = 2.7V, Gain = 5, RL = 10k ●13.85 13.95 14.05 13.83 13.95 14.05 dB

VS = 2.7V, Gain = 10, RL = 10k

VS = 2.7V, Gain = 10, RL = 500Ω

●

19.7

19.6

19.9

19.85

20.1

19.7

19.4

19.9

19.85

20.1

VS = 2.7V, Gain = 20, RL = 10k ●25.7 25.9 26.1 25.65 25.9 26.1 dB

VS = 2.7V, Gain = 50, RL = 10k ●33.5 33.8 34.1 33.4 33.8 34.1 dB

VS = 2.7V, Gain = 100, RL = 10k

VS = 2.7V, Gain = 100, RL = 500Ω

●

36.4

39.6

38.5

40.2

40.1

38.7

35.4

39.6

38.5

40.2

40.1

VS = 5V, Gain = 1, RL = 10k

VS = 5V, Gain = 1, RL = 500Ω

●

–0.05

–0.1

–0.01

0.07

0.08

–0.05

–0.11

–0.01

0.07

0.08

VS = 5V, Gain = 2, RL = 10k ●5.96 6.02 6.08 5.955 6.02 6.08 dB

VS = 5V, Gain = 5, RL = 10k ●13.8 13.95 14.1 13.75 13.95 14.1 dB

VS = 5V, Gain = 10, RL = 10k

VS = 5V, Gain = 10, RL = 500Ω

●

19.8

19.6

19.9

19.85

20.1

19.75

19.45

19.9

19.85

20.1

VS = 5V, Gain = 20, RL = 10k ●25.8 25.9 26.1 25.70 25.9 26.1 dB

VS = 5V, Gain = 50, RL = 10k ●33.5 33.8 34.1 33.4 33.8 34.1 dB

VS = 5V, Gain = 100, RL = 10k

VS = 5V, Gain = 100, RL = 500Ω

●

39.3

39.7

38.7

40.1

39.1

39.7

38.7

40.1

VS = ±5V, Gain = 1, RL = 10k

VS = ±5V, Gain = 1, RL = 500Ω

●

–0.05

–0.1

–0.01

0.07

0.08

–0.05

–0.1

–0.01

0.07

0.08

VS = ±5V, Gain = 2, RL = 10k ●5.96 6.02 6.08 5.96 6.02 6.08 dB

VS = ±5V, Gain = 5, RL = 10k ●13.80 13.95 14.1 13.80 13.95 14.1 dB

VS = ±5V, Gain = 10, RL = 10k

VS = ±5V, Gain = 10, RL = 500Ω

●

19.8

19.7

19.9

20.1

19.75

19.6

19.9

20.1

VS = ±5V, Gain = 20, RL = 10k ●25.8 25.95 26.1 25.75 25.95 26.1 dB

VS = ±5V, Gain = 50, RL = 10k ●33.7 33.85 34 33.6 33.85 34 dB

VS = ±5V, Gain = 100, RL = 10k

VS = ±5V, Gain = 100, RL = 500Ω

●

39.4

37.8

39.8

39.1

40.2

40.1

39.25

39.8

39.1

40.2

40.1

Offset Voltage Magnitude (Internal Op Amp)

(VOS(OA)) (Note 8)

●1.5 9 1.5 11 mV

Offset Voltage Drift (Internal Op Amp) (Note 8) 6 8 µV/°C

Offset Voltage Magnitude

(Referred to “IN” Pin) (VOS(IN))

Gain = 1

Gain = 10

●

1.7

DC Input Resistance (Note 9) DC VIN = 0V

Gain = 0

Gain = 1

Gain = 2

Gain = 5

Gain = 10, 20, 50, 100

●

>100

MΩ

kΩ

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k

to mid-supply point, unless otherwise noted.

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

elecTrical characTerisTics

PARAMETER CONDITIONS

LTC6910-1C/LTC6910-1I

LTC6910-1H

UNITMIN TYP MAX MIN TYP MAX

Specifications for LTC6910-1 Only

DC Small-Signal Output Resistance Gain = 0

Gain = 1

Gain = 2

Gain = 5

Gain = 10

Gain = 20

Gain = 50

Gain = 100

0.4

0.7

1.9

3.4

6.4

0.4

0.7

1.9

3.4

6.4

Gain-Bandwidth Product Gain = 100, fIN = 200kHz

●

MHz

Wideband Noise (Referred to Input) f = 1kHz to 200kHz

Gain = 0 Output Noise

Gain = 1

Gain = 2

Gain = 5

Gain = 10

Gain = 20

Gain = 50

Gain = 100

3.8

10.7

7.3

5.2

4.5

4.2

3.9

3.4

3.8

10.7

7.3

5.2

4.5

4.2

3.9

3.4

µVRMS

Voltage Noise Density (Referred to Input) f = 50kHz

Gain = 1

Gain = 2

Gain = 5

Gain = 10

Gain = 20

Gain = 50

Gain = 100

9.4

8.7

7.6

9.4

8.7

7.6

nV/√Hz

Total Harmonic Distortion Gain = 10, fIN = 10kHz, VOUT = 1VRMS –90

0.003

–90

0.003

Gain = 10, fIN = 100kHz, VOUT = 1VRMS –77

0.014

–77

0.014

AGND (Common Mode) Input Voltage Range

(Note 10)

VS = 2.7V

VS = 5V

VS = ±5V

●

0.55

0.7

–4.3

1.6

3.65

3.5

0.7

–4.3

1.5

3.25

3.35

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k

to mid-supply point, unless otherwise noted.

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

elecTrical characTerisTics

PARAMETER CONDITIONS

LTC6910-2C/LTC6910-2I

LTC6910-2H

UNIT

MIN TYP MAX MIN TYP MAX

Specifications for LTC6910-2 Only

Voltage Gain (Note 7) VS = 2.7V, Gain = 1, RL = 10k

VS = 2.7V, Gain = 1, RL = 500Ω

–0.06

–0.1

–0.02

0.08

0.06

–0.07

–0.11

–0.02

0.08

0.06

VS = 2.7V, Gain = 2, RL = 10k l5.96 6.02 6.1 5.95 6.02 6.1 dB

VS = 2.7V, Gain = 4, RL = 10k l11.9 12.02 12.12 11.9 12.02 12.12 dB

VS = 2.7V, Gain = 8, RL = 10k

VS = 2.7V, Gain = 8, RL = 500Ω

17.8

17.65

17.98

17.95

18.15

17.8

17.55

17.98

17.95

18.15

VS = 2.7V, Gain = 16, RL = 10k l23.75 24 24.2

23.75

24 24.2 dB

VS = 2.7V, Gain = 32, RL = 10k l29.7 30 30.2

29.65

30 30.2 dB

VS = 2.7V, Gain = 64, RL = 10k

VS = 2.7V, Gain = 64, RL = 500Ω

35.3

33.2

35.75

34.8

36.2

35.2

32.7

35.75

34.8

36.2

VS = 5V, Gain = 1, RL = 10k

VS = 5V, Gain = 1, RL = 500Ω

–0.06

–0.1

–0.01

0.08

–0.06

–0.11

–0.01

0.08

VS = 5V, Gain = 2, RL = 10k l5.96 6.02 6.1 5.96 6.02 6.1 dB

VS = 5V, Gain = 4, RL = 10k l11.85 12.02 12.15

11.85

12.02 12.15 dB

VS = 5V, Gain = 8, RL = 10k

VS = 5V, Gain = 8, RL = 500Ω

17.85

17.65

17.9

18.15

17.85

17.6

17.9

18.15

VS = 5V, Gain = 16, RL = 10k l23.85 24 24.15

23.78

24 24.15 dB

VS = 5V, Gain = 32, RL = 10k l29.7 30 30.2 29.7 30 30.2 dB

VS = 5V, Gain = 64, RL = 10k

VS = 5V, Gain = 64, RL = 500Ω

35.6

33.8

35.9

36.2

35.5

33.2

35.9

36.2

VS = ±5V, Gain = 1, RL = 10k

VS = ±5V, Gain = 1, RL = 500Ω

–0.05

–0.1

–0.01

0.07

0.08

–0.05

–0.1

–0.01

0.07

0.08

VS = ±5V, Gain = 2, RL = 10k l5.96 6.02 6.1 5.96 6.02 6.1 dB

VS = ±5V, Gain = 4, RL = 10k l11.9 12.02 12.15 11.9 12.02 12.15 dB

VS = ±5V, Gain = 8, RL = 10k

VS = ±5V, Gain = 8, RL = 500Ω

17.85

17.80

17.95

18.15

18.1

17.85

17.72

17.95

18.15

18.1

VS = ±5V, Gain = 16, RL = 10k l23.85 24 24.15 23.8 24 24.15 dB

VS = ±5V, Gain = 32, RL = 10k l29.85 30 30.15

29.78

30 30.15 dB

VS = ±5V, Gain = 64, RL = 10k

VS = ±5V, Gain = 64, RL = 500Ω

35.7

34.2

35.95

35.3

36.2

35.7

33.8

35.95

35.3

36.2

Offset Voltage Magnitude (Internal Op Amp)

(VOS(OA)) (Note 8)

l1.5 9 1.5 11 mV

Offset Voltage Drift (Internal Op Amp) (Note 8) l6 8 µV/°C

Offset Voltage Magnitude

(Referred to “IN” Pin) (VOS(IN))

Gain = 1

Gain = 8

DC Input Resistance (Note 9) DC VIN = 0V

Gain = 0

Gain = 1

Gain = 2

Gain = 4

Gain = 8, 16, 32, 64

>100

2.5

1.25

>100

2.5

1.25

MΩ

kΩ

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k

to mid-supply point, unless otherwise noted.

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

elecTrical characTerisTics

PARAMETER CONDITIONS

LTC6910-2C/LTC6910-2I

LTC6910-2H

UNIT

MIN TYP MAX MIN TYP MAX

Specifications for LTC6910-2 Only

DC Small-Signal Output Resistance Gain = 0

Gain = 1

Gain = 2

Gain = 4

Gain = 8

Gain = 16

Gain = 32

Gain = 64

0.4

0.7

1.6

2.8

0.4

0.7

1.6

2.8

Gain-Bandwidth Product Gain = 64, fIN = 200kHz

MHz

Wideband Noise (Referred to Input) f = 1kHz to 200kHz

Gain = 0 Output Noise

Gain = 1

Gain = 2

Gain = 4

Gain = 8

Gain = 16

Gain = 32

Gain = 64

3.8

10.7

7.3

5.3

4.6

4.2

3.6

3.8

10.7

7.3

5.3

4.6

4.2

3.6

µVRMS

Voltage Noise Density (Referred to Input) f = 50kHz

Gain = 1

Gain = 2

Gain = 4

Gain = 8

Gain = 16

Gain = 32

Gain = 64

10.3

9.4

8.1

10.3

9.4

8.1

nV/√Hz

Total Harmonic Distortion Gain = 8, fIN = 10kHz, VOUT = 1VRMS –90

0.003

–90

0.003

Gain = 8, fIN = 100kHz, VOUT = 1VRMS –77

0.014

–77

0.014

AGND (Common Mode) Input Voltage Range

(Note 10)

VS = 2.7V

VS = 5V

VS = ±5V

0.85

0.7

–4.3

1.55

3.6

3.4

0.85

0.7

–4.3

1.55

3.6

3.4

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k

to mid-supply point, unless otherwise noted.

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

elecTrical characTerisTics

PARAMETER CONDITIONS

LTC6910-3C/LTC6910-3I LTC6910-2H

UNIT

MIN TYP MAX MIN TYP MAX

Specifications for LTC6910-3 Only

Voltage Gain (Note 7) VS = 2.7V, Gain = 1, RL = 10k

VS = 2.7V, Gain = 1, RL = 500Ω

–0.05

–0.1

–0.02

0.07

0.06

–0.05

–0.11

–0.02

0.09

0.06

VS = 2.7V, Gain = 2, RL = 10k l5.93 6.02 6.08 5.93 6.02 6.09 dB

VS = 2.7V, Gain = 3, RL = 10k l9.35 9.5 9.7 9.35 9.5 9.75 dB

VS = 2.7V, Gain = 4, RL = 10k

VS = 2.7V, Gain = 4, RL = 500Ω

11.9

11.8

11.98

12.2

11.9

11.75

11.98

12.2

VS = 2.7V, Gain = 5, RL = 10k l13.85 13.92 14.05 13.8 13.92 14.05 dB

VS = 2.7V, Gain = 6, RL = 10k l15.4 15.5 15.6 15.4 15.5 15.6 dB

VS = 2.7V, Gain = 7, RL = 10k

VS = 2.7V, Gain = 7, RL = 500Ω

16.7

16.55

16.85

16.8

16.7

16.47

16.85

16.8

VS = 5V, Gain = 1, RL = 10k

VS = 5V, Gain = 1, RL = 500Ω

–0.05

–0.1

–0.01

0.07

0.08

–0.05

–0.1

–0.01

0.07

0.08

VS = 5V, Gain = 2, RL = 10k l5.96 6.02 6.08 5.96 6.02 6.08 dB

VS = 5V, Gain = 3, RL = 10k l9.45 9.54 9.65 9.45 9.54 9.65 dB

VS = 5V, Gain = 4, RL = 10k

VS = 5V, Gain = 4, RL = 500Ω

11.85

11.8

12.02

11.95

12.15

11.85

11.75

12.02

11.95

12.15

VS = 5V, Gain = 5, RL = 10k l13.8 13.95 14.05 13.8 13.95 14.05 dB

VS = 5V, Gain = 6, RL = 10k l15.35 15.5 15.65 15.35 15.5 15.65 dB

VS = 5V, Gain = 7, RL = 10k

VS = 5V, Gain = 7, RL = 500Ω

16.7

16.6

16.85

16.8

16.7

16.5

16.85

16.8

VS = ±5V, Gain = 1, RL = 10k

VS = ±5V, Gain = 1, RL = 500Ω

–0.06

–0.1

–0.01

0.07

0.08

–0.06

–0.12

–0.01

0.07

0.08

VS = ±5V, Gain = 2, RL = 10k l5.96 6.02 6.08 5.96 6.02 6.08 dB

VS = ±5V, Gain = 3, RL = 10k l9.4 9.54 9.65 9.4 9.54 9.65 dB

VS = ±5V, Gain = 4, RL = 10k

VS = ±5V, Gain = 4, RL = 500Ω

11.85

11.8

12.2

11.85

11.8

12.2

VS = ±5V, Gain = 5, RL = 10k l13.8 13.95 14.1 13.8 13.95 14.1 dB

VS = ±5V, Gain = 6, RL = 10k l15.35 15.5 15.7 15.35 15.5 15.7 dB

VS = ±5V, Gain = 7, RL = 10k

VS = ±5V, Gain = 7, RL = 500Ω

16.7

16.65

16.85

16.8

17.05

16.7

16.6

16.85

16.8

17.05

Offset Voltage Magnitude (Internal Op Amp)

(VOS(OA)) (Note 8)

l1.5 8 1.5 8 mV

Offset Voltage Drift (Internal Op Amp) (Note 8) l6 8 µV/°C

Offset Voltage Magnitude

(Referred to “IN” Pin) (VOS(IN))

Gain = 1

Gain = 4

1.9

DC Input Resistance (Note 9) DC VIN = 0V

Gain = 0

Gain = 1

Gain = 2

Gain = 3

Gain = 4

Gain = 5

Gain = 6

Gain = 7

>100

3.3

2.5

1.7

1.4

>100

3.3

2.5

1.7

1.4

MΩ

kΩ

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k

to mid-supply point, unless otherwise noted.

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

elecTrical characTerisTics

PARAMETER CONDITIONS

LTC6910-3C/LTC6910-3I LTC6910-2H

UNIT

MIN TYP MAX MIN TYP MAX

Specifications for LTC6910-3 Only

DC Small-Signal Output Resistance Gain = 0

Gain = 1

Gain = 2

Gain = 3

Gain = 4

Gain = 5

Gain = 6

Gain = 7

0.4

0.7

1.3

1.6

1.9

2.2

2.5

0.4

0.7

1.3

1.6

1.9

2.2

2.5

Gain-Bandwidth Product Gain = 7, fIN = 200kHz l11 11 MHz

Wideband Noise (Referred to Input) f = 1kHz to 200kHz

Gain = 0 Output Noise

Gain = 1

Gain = 2

Gain = 3

Gain = 4

Gain = 5

Gain = 6

Gain = 7

3.8

10.7

7.3

6.1

5.3

5.2

4.9

4.7

3.8

10.7

7.3

6.1

5.3

5.2

4.9

4.7

µVRMS

Voltage Noise Density (Referred to Input) f = 50kHz

Gain = 1

Gain = 2

Gain = 3

Gain = 4

Gain = 5

Gain = 6

Gain = 7

11.6

11.2

10.5

11.6

11.2

10.5

nV/√Hz

Total Harmonic Distortion Gain = 4, fIN = 10kHz, VOUT = 1VRMS –90

0.003

–90

0.003

Gain = 4, fIN = 100kHz, VOUT = 1VRMS –80

0.01

–80

0.01

AGND (Common Mode) Input Voltage Range

(Note 10)

VS = 2.7V

VS = 5V

VS = ±5V

0.85

0.7

–4.3

1.55

3.6

3.4

0.85

0.7

–4.3

1.55

3.6

3.4

The l denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at TA = 25°C. VS = 5V, AGND = 2.5V, Gain = 1 (Digital Inputs 001), RL = 10k

to mid-supply point, unless otherwise noted.

Note 1: Absolute Maximum Ratings are those values beyond which the life

of the device may be impaired.

Note 2: The LTC6910-XC and LTC6910-XI are guaranteed functional over

the operating temperature range of –40°C to 85°C. The LTC6910-XH are

guaranteed functional over the operating temperature range of –40°C to

125°C.

Note 3: The LTC6910-XC are guaranteed to meet specified performance

from 0°C to 70°C. The LTC6910-XC are designed, characterized and

expected to meet specified performance from – 40°C to 85°C but are not

tested or QA sampled at these temperatures. LTC6910-XI are guaranteed

to meet specified performance from –40°C to 85°C. The LTC6910-XH are

guaranteed to meet specified performance from –40°C to 125°C.

Note 4: Operating all three logic inputs at 0.5V causes the supply current

to increase typically 0.1mA from this specification.

Note 5: Output voltage swings are measured as differences between the

output and the respective supply rail.

Note 6: Extended operation with output shorted may cause junction

temperature to exceed the 150°C limit and is not recommended.

Note 7: Gain is measured with a DC large-signal test using an output

excursion between approximately 30% and 70% of supply voltage.

Note 8: Offset voltage referred to “IN” pin is (1 + 1/G) times offset

voltage of the internal op amp, where G is nominal gain magnitude. See

Applications Information.

Note 9: Input resistance can vary by approximately ±30% part-to-part at a

given gain setting.

Note 10: At limits of AGND input range, open-loop gain of internal op

amp may be greater than, or as much as 15dB below, its value at nominal

AGND value.

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

Typical perForMance characTerisTics

LTC6910-1 Output Voltage Swing

vs Load Current

TEMPERATURE (°C)

–0.2

GAIN CHANGE (dB)

–0.1

0.1

0.2

6910 G01

–50 0 50 150100

GAIN = 100

GAIN = 10

GAIN = 1

VS = ±2.5V

OUTPUT UNLOADED

FREQUENCY (Hz)

GAIN (dB)

100 10k 100k 1M 10M

6910 G02

–10 1k

GAIN OF 100

GAIN OF 1

GAIN OF 2

GAIN OF 5

GAIN OF 10

GAIN OF 20

GAIN OF 50

VS = ±5V, VIN = 5mVRMS

GAIN

–3dB FREQUENCY (MHz)

2.0

4.0

8.0

•

7.5

7.0

6.5

5.5

5.0

4.5

3.5

3.0

2.5

1.5

1.0

0.5

10 100

6910 G03

6.0

VIN = 5mVRMS

VS = 2.7V

VS = ±5V

•

••

LTC6910-1 Frequency Response

LTC6910-1 –3dB Bandwidth

vs Gain Setting

LTC6910-1 Power Supply

Rejection vs Frequency

LTC6910-1 Noise Density

vs Frequency

OUTPUT CURRENT (mA)

OUTPUT VOTLAGE SWING (V)

(REFERRED TO SUPPLY VOLTAGE)

+VS

–VS

0.01 1 10 100

6910 G04

0.1

+VS – 0.5

–VS + 0.5

+VS – 1.0

–VS + 1.0

+VS – 1.5

–VS + 1.5

+VS – 2.0

–VS + 2.0

VS = ±2.5V

125°C

25°C

–40°C

SOURCE

SINK

FREQUENCY (kHz)

REJECTION (dB)

0.1 10 100 1000

6910 G05

+SUPPLY

–SUPPLY

VS = ±2.5V

GAIN = 1

FREQUENCY (kHz)

100

6910 G06

110

100

GAIN = 1

GAIN = 10

GAIN = 100

INPUT-REFERRED

VS = ±2.5V

TA = 25°C

VOLTAGE NOISE DENSITY (nV/√Hz)

LTC6910-1 Distortion with Light

Loading (RL = 10k)

LTC6910-1 THD + Noise

vs Input Voltage

FREQUENCY (kHz)

–60

–50

–30

150

6910 G07

–70

–80

50 100

GAIN = 100

GAIN = 10

GAIN = 1

200

–90

–100

–40

0.1

0.3

0.03

0.01

0.003

0.001

THD (AMPLITUDE BELOW FUNDAMENTAL) (dB)

THD (%)

VS = ±2.5V

VOUT = 1VRMS (2.83VP-P)

THD MEASURES HD2 AND HD3

FREQUENCY (kHz)

–60

–50

–30

150

6910 G08

–70

–80

50 100

GAIN = 100

GAIN = 10

GAIN = 1

200

–90

–100

–40

0.1

0.3

0.03

0.01

0.003

0.001

THD (AMPLITUDE BELOW FUNDAMENTAL) (dB)

THD (%)

VS = ±2.5V

VOUT = 1VRMS (2.83VP-P)

THD MEASURES HD2 AND HD3

INPUT VOLTAGE (VP-P)

0.01

–60

(THD + NOISE)/SIGNAL (dB)

–50

–40

–30

–20

0.1 1 10

6910 G09

–70

–80

–100

–110

–90

fIN = 1kHz

VS = ±5V

NOISE BW = 22kHz

GAIN SETTING = 100

GAIN SETTING = 10

GAIN SETTING = 1

LTC6910-1 Distortion with Heavy

Loading (RL = 500Ω)

LTC6910-1 Gain Shift

vs Temperature

(LTC6910-1)

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

Typical perForMance characTerisTics

LTC6910-2 Output Voltage Swing

vs Load Current

TEMPERATURE (°C)

–0.2

GAIN CHANGE (dB)

–0.1

0.1

0.2

6910 G10

–50 0 50 150100

GAIN = 64

GAIN = 8

GAIN = 1

VS = ±2.5V

OUTPUT UNLOADED

FREQUENCY (Hz)

GAIN (dB)

100 1k 100k 1M 10M

6910 G11

–10 10k

VS = ±5V

VIN = 10mVRMS

GAIN OF 64

GAIN OF 32

GAIN OF 16

GAIN OF 4

GAIN OF 8

GAIN OF 2

GAIN OF 1

GAIN

–3dB FREQUENCY (MHz)

2.0

4.0

8.0

7.5

7.0

6.5

5.5

5.0

4.5

3.5

3.0

2.5

1.5

1.0

0.5

10 100

6910 G12

6.0

VIN = 10mVRMS

VS = 2.7V

VS = ±5V

•

•••

•

LTC6910-2 Frequency Response

LTC6910-2 –3dB Bandwidth

vs Gain Setting

LTC6910-2 Power Supply

Rejection vs Frequency

LTC6910-2 Noise Density

vs Frequency

OUTPUT CURRENT (mA)

OUTPUT VOTLAGE SWING (V)

(REFERRED TO SUPPLY VOLTAGE)

+VS

–VS

0.01 1 10 100

6910 G13

0.1

+VS – 0.5

–VS + 0.5

+VS – 1.0

–VS + 1.0

+VS – 1.5

–VS + 1.5

+VS – 2.0

–VS + 2.0

VS = ±2.5V

125°C

25°C

–40°C

SOURCE

SINK

FREQUENCY (kHz)

REJECTION (dB)

0.1 10 100 1000

6910 G14

+SUPPLY

–SUPPLY

VS = ±2.5V

GAIN = 1

FREQUENCY (kHz)

100

6910 G15

110

100

GAIN = 1

GAIN = 8

GAIN = 64

INPUT-REFERRED

VS = ±2.5V

TA = 25°C

VOLTAGE NOISE DENSITY (nV/Hz)

LTC6910-2 Distortion with Light

Loading (RL = 10k)

LTC6910-2 THD + Noise

vs Input Voltage

FREQUENCY (kHz)

–60

–50

–30

150

6910 G16

–70

–80

50 100

GAIN = 64

GAIN = 8

GAIN = 1

200

–90

–100

–40

0.1

0.3

0.03

0.01

0.003

0.001

THD (AMPLITUDE BELOW FUNDAMENTAL) (dB)

THD (%)

VS = ±2.5V

VOUT = 1VRMS (2.83VP-P)

THD MEASURES HD2 AND HD3

FREQUENCY (kHz)

–60

–50

–30

150

6910 G17

–70

–80

50 100

GAIN = 64

GAIN = 8

GAIN = 1

200

–90

–100

–40

0.1

0.3

0.03

0.01

0.003

0.001

THD (AMPLITUDE BELOW FUNDAMENTAL) (dB)

THD (%)

VS = ±2.5V

VOUT = 1VRMS (2.83VP-P)

THD MEASURES HD2 AND HD3

INPUT VOLTAGE (VP-P)

0.01

–60

(THD + NOISE)/SIGNAL (dB)

–50

–40

–30

–20

0.1 1 10

6910 G18

–70

–80

–100

–110

–90 fIN = 1kHz

VS = ±5V

NOISE BW = 22kHz

GAIN

SETTING = 64

GAIN

SETTING = 8

GAIN SETTING = 1

LTC6910-2 Distortion with Heavy

Loading (RL = 500Ω)

LTC6910-2 Gain Shift

vs Temperature

(LTC6910-2)

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

Typical perForMance characTerisTics

LTC6910-3 Output Voltage Swing

vs Load Current

TEMPERATURE (°C)

–0.02

GAIN CHANGE (dB)

–0.01

0.01

0.02

6910 G19

–50 0 50 150100

GAIN = 7

GAIN = 4

GAIN = 1

VS = ±2.5V

OUTPUT UNLOADED

FREQUENCY (Hz)

GAIN (dB)

–5

1k100 100k 1M 10M

6910 G20

–10 10k

GAIN OF 7 GAIN OF 6

GAIN OF 5

GAIN OF 4

GAIN OF 3

GAIN OF 2

GAIN OF 1

VS = ±5V

VIN = 10mVRMS

GAIN

–3dB FREQUENCY (MHz)

2.0

4.0

8.0

7.0

5.0

3.0

1.0

6910 G21

6.0

VIN = 10mVRMS

VS = 2.7V

VS = ±5V

•

••••

•

•••

•

1 3 10

2 4 5 67 8 9

LTC6910-3 Frequency Response

LTC6910-3 –3dB Bandwidth

vs Gain Setting

LTC6910-3 Power Supply

Rejection vs Frequency

LTC6910-3 Noise Density

vs Frequency

OUTPUT CURRENT (mA)

OUTPUT VOTLAGE SWING (V)

(REFERRED TO SUPPLY VOLTAGE)

+VS

–VS

0.01 1 10 100

6910 G22

0.1

+VS – 0.5

–VS + 0.5

+VS – 1.0

–VS + 1.0

+VS – 1.5

–VS + 1.5

+VS – 2.0

–VS + 2.0

VS = ±2.5V

125°C

25°C

–40°C

SOURCE

SINK

FREQUENCY (kHz)

REJECTION (dB)

0.1 10 100 1000

6910 G23

+SUPPLY

–SUPPLY

VS = ±2.5V

GAIN = 1

FREQUENCY (kHz)

100

6910 G24

110

100

GAIN = 1

GAIN = 4

GAIN = 7

INPUT-REFERRED

VS = ±2.5V

TA = 25°C

VOLTAGE NOISE DENSITY (nV/√Hz)

LTC6910-3 Distortion with Light

Loading (RL = 10k)

LTC6910-3 THD + Noise

vs Input Voltage

FREQUENCY (kHz)

–60

–50

–30

150

6910 G25

–70

–80

50 100 200

–90

–100

–40

0.1

0.3

0.03

0.01

0.003

0.001

THD (AMPLITUDE BELOW FUNDAMENTAL) (dB)

THD (%)

VS = ±2.5V

VOUT = 1VRMS (2.83VP-P)

THD MEASURES HD2 AND HD3

GAIN = 7

GAIN = 1

GAIN = 4

FREQUENCY (kHz)

–60

–50

–30

150

6910 G26

–70

–80

50 100

GAIN = 7

GAIN = 1

200

–90

–100

–40

0.1

0.3

0.03

0.01

0.003

0.001

THD (AMPLITUDE BELOW FUNDAMENTAL) (dB)

THD (%)

VS = ±2.5V

VOUT = 1VRMS (2.83VP-P)

THD MEASURES HD2 AND HD3

GAIN = 4

INPUT VOLTAGE (VP-P)

0.01

–60

(THD + NOISE)/SIGNAL (dB)

–50

–40

–30

–20

0.1 1 10

6910 G27

–70

–80

–100

–110

–90

fIN = 1kHz

VS = ±5V

NOISE BW = 22kHz

GAIN SETTING = 7

GAIN SETTING = 4

GAIN SETTING = 1

LTC6910-3 Distortion with Heavy

Loading (RL = 500Ω)

LTC6910-3 Gain Shift

vs Temperature

(LTC6910-3)

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

pin FuncTions

OUT (Pin 1): Analog Output. This is the output of an inter-

nal operational amplifier and swings to near the power

supply rails (V+ and V–) as specified in the Electrical

Characteristics table. The internal op amp remains active

at all times, including the zero gain setting (digital input

000). As with other amplifier circuits, loading the out-

put as lightly as possible will minimize signal distortion

and gain error. The Electrical Characteristics table shows

performance at output currents up to 10mA and current

limits that occur when the output is shorted to mid-supply

at 2.7V and ±5V supplies. Signal outputs above 10mA are

possible but current-limiting circuitry will begin to affect

amplifier performance at approximately 20mA. Long-term

operation above 20mA output is not recommended. Do

not exceed maximum junction temperature of 150°C. The

output will drive capacitive loads up to 50pF. Capacitances

higher than 50pF should be isolated by a series resistor

to preserve AC stability.

AGND (Pin 2): Analog Ground. The AGND pin is at the

midpoint of an internal resistive voltage divider, develop-

ing a potential halfway between the V+ and V– pins, with

an equivalent series resistance to the pin of nominally

5kΩ (Figure 4). AGND is also the noninverting input of the

internal op amp, which makes it the ground reference volt-

age for the IN and OUT pins. Because of this, very “clean”

grounding is important, including an analog ground plane

surrounding the package.

Recommended analog ground plane connection depends

on how power is applied to the LTC6910-X (Figures 1, 2,

and 3). Single power supply applications typically use V–

for the system signal ground. The analog ground plane

in single-supply applications should therefore tie to V–,

and the AGND pin should be bypassed to this ground

plane by a high quality capacitor of at least 1µF (Figure 1).

The AGND pin then provides an internal analog reference

voltage at half the supply voltage (with internal resistance

of approximately 5kΩ) which is the center of the swing

range for both input and output. Dual supply applications

with symmetrical supplies (such as ±5V) have a natural

system ground at zero volts, which can drive the analog

ground plane; AGND then connects directly to the ground

plane, making zero volts the input and output reference

voltage for the LTC6910-X (Figure 2). Finally, if a dual

power supply is asymmetrical, the supply ground is still

the natural ground plane voltage. To maximize signal

swing capability with an asymmetrical supply, however,

it is often desirable to refer the LTC6910-X’s analog input

and output to a voltage equidistant from the two supply

rails V+ and V–. The AGND pin will provide such a poten-

tial when open-circuited and bypassed with a capacitor

(Figure 3), just as with a single power supply, but now the

ground plane connection is different and the LTC6910-X’s

V+ and V– pins are both isolated from this ground plane.

LTC6910-X

DIGITAL GROUND PLANE

(IF ANY)

ANALOG

GROUND

PLANE

SINGLE-POINT

SYSTEM GROUND

2 3 4

REFERENCE

V+

6910 F01

8 7 6 5

0.1µF

V+

1µF

LTC6910-X

DIGITAL GROUND PLANE

(IF ANY)

ANALOG

GROUND

PLANE

SINGLE-POINT

SYSTEM GROUND

2 3 4

6910 F02

8 7 6 5

0.1µF

V+

0.1µF

V–

Figure 2. Symmetrical Dual Supply

Ground Plane Connection

Figure 1. Single Supply

Ground Plane Connection

LTC6910-X

DIGITAL GROUND PLANE

(IF ANY)

ANALOG

GROUND

PLANE

SINGLE-POINT

SYSTEM GROUND

2 3 4

6910 F03

8 7 6 5

0.1µF

V+

0.1µF

1µF

V–

MID-SUPPLY

REFERENCE

Figure 3. Asymmetrical Dual

Supply Ground Plane Connection

LTC6910-1/

LTC6910-2/LTC6910-3

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pin FuncTions

–

INPUT R ARRAY FEEDBACK R ARRAY

V–

6910 F04

OUT

V+10k

MOS-INPUT

OP AMP

AGND

10k

V–

V+

G1G2 G0

CMOS LOGIC

67 5

Figure 4. Block Diagram

Where AGND does not connect to a ground plane, as in

Figures 1 and 3, it is important to AC-bypass the AGND

pin. This is especially true when AGND is used as a refer-

ence voltage for other circuitry. Also, without a bypass

capacitor, wideband noise will enter the signal path from

the internal voltage divider resistors that set the DC volt-

age on AGND. This noise can reduce SNR by 3dB at high

gain settings. The resistors present a Thévenin equivalent

of approximately 5k to the AGND pin. An external capaci-

tor from AGND to the ground plane, whose impedance

is well below 5k at frequencies of interest, will suppress

this noise. A 1µF high quality capacitor is effective in sup-

pressing resistor noise for frequencies down to 1kHz.

Larger capacitors extend this suppression to propor-

tionately lower frequencies. This issue does not arise in

symmetrical dual supply applications (Figure 2) because

AGND goes directly to ground.

In applications requiring an analog ground reference

other than halfway between the supply rails, the user can

override the built-in analog ground reference by tying the

AGND pin to a reference voltage within the AGND voltage

range specified in the Electrical Characteristics table. The

AGND pin will load the external reference with approxi-

mately 5k returned to the mid-supply potential. AGND

should still be capacitively bypassed to a ground plane as

noted above. Do not connect the AGND pin to the V– pin.

IN (Pin 3): Analog Input. The input signal to the amplifier

in the LTC6910-X is the voltage difference between the

IN and AGND pins. The IN pin connects internally to a

digitally controlled resistance whose other end is a cur-

rent summing point at the same potential as the AGND pin

(Figure4). At unity gain (digital input 001), the value of this

input resistance

is approximately 10kΩ and the IN volt-

age range is rail-to-rail (V+ to V–). At gain settings above

unity (digital input 010 or higher), the input resistance

falls. Also, the linear input voltage range falls in inverse

proportion to gain. (The higher gains are designed to

boost lower level signals with good noise performance.)

Tables 1, 2, and 3 summarize this behavior. In the “zero”

gain state (digital input 000), analog switches disconnect

the IN pin internally and this pin presents a very high

input resistance. The input may vary from rail to rail in

the “zero” gain setting but the output is insensitive to it

and remains at the AGND potential. Circuitry driving the

IN pin must consider the LTC6910-X’s input resistance

and the variation of this resistance when used at mul-

tiple gain settings. Signal sources with significant output

resistance may introduce a gain error as the source’s

output resistance and the LTC6910-X’s input resistance

form a voltage divider. This is especially true at the higher

gain settings where the input resistance is lowest.

In single supply voltage applications at elevated gain

settings (digital input 010 or higher), it is important to

remember that the LTC6910-X’s DC ground reference for

both input and output is AGND, not V–. With increasing

gains, the LTC6910-X’s input voltage range for unclipped

output is no longer rail-to-rail but shrinks toward AGND.

The OUT pin also swings positive or negative with respect

to AGND. At unity gain (digital input 001), both IN and

OUT voltages can swing from rail to rail (Tables 1, 2, 3).

LTC6910-1/

LTC6910-2/LTC6910-3

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pin FuncTions

–

, V

(Pins 4, 8): Power Supply Pins. The V

and V

–

pins

should be bypassed with 0.1µF capacitors to an adequate

analog ground plane using the shortest possible wiring.

Electrically clean supplies and a low impedance ground

are important for the high dynamic range available from

the LTC6910-X (see further details under AGND). Low

noise linear power supplies are recommended. Switching

power supplies require special care to prevent switching

noise coupling into the signal path, reducing dynamic

range.

G0, G1, G2 (Pins 5, 6, 7): CMOS-Level Digital Gain-

Control Inputs. G2 is the most significant bit (MSB).

These pins control the voltage gain from IN to OUT pins

(see Table1, Table 2 and Table 3). Digital input code 000

causes a “zero” gain with very low output noise. In this

“zero” gain state the IN pin is disconnected internally, but

the OUT pin remains active and forced by the internal op

amp to the voltage present on the AGND pin. Note that the

voltage gain from IN to OUT is inverting: OUT and IN pins

always swing on opposite sides of the AGND potential.

The G pins are high impedance CMOS logic inputs and

must be connected (they will float to unpredictable volt-

ages if open circuited). No speed limitation is associated

with the digital logic because it is memoryless and much

faster than the analog signal path.

LTC6910-1/

LTC6910-2/LTC6910-3

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Functional Description

The LTC6910 family are small outline, wideband inverting

DC amplifiers whose voltage gain is digitally program-

mable. Each delivers a choice of eight voltage gains,

controlled by the 3-bit digital inputs to the G pins, which

accept CMOS logic levels. The gain code is always mono-

tonic; an increase in the 3-bit binary number (G2 G1 G0)

causes an increase in the gain. Table 1, Table 2 and Table3

list the nominal voltage gains for LTC6910-1, LTC6910-2

and LTC6910-3 respectively. Gain control within each

amplifier occurs by switching resistors from a matched

array in or out of a closed-loop op amp circuit using MOS

analog switches (Figure 4). Bandwidth depends on gain

setting. Curves in the Typical Performance Characteristics

section show measured frequency responses.

Digital Control

Logic levels for the LTC6910-X digital gain control inputs

(Pins 5, 6, 7) are nominally rail-to-rail CMOS. Logic 1

is V

, logic 0 is V

–

or alternatively 0V when using ±5V

supplies. The part is tested with the values listed in the

Electrical Characteristics table (Digital Input “High” and

“Low” Voltages), which are 10% and 90% of full excur-

sion on the inputs. That is, the tested logic levels are

0.27V and 2.43V with a 2.7V supply, 0.5V and 4.5V levels

with 0V and 5V supply rails, and 0.5V and 4.5V logic levels

at ±5V supplies. Do not attempt to drive the digital inputs

with TTL logic levels (such as HCT or LS logic), which

normally do not swing near +5V. TTL sources should be

adapted with CMOS drivers or suitable pull-up resistors

to 5V so that they will swing to the positive rail.

Timing Constraints

Settling time in the CMOS gain-control logic is typically

several nanoseconds and faster than the analog signal

path. When amplifier gain changes, the limiting timing

is analog, not digital, because the effects of digital input

changes are observed only through the analog output

(Figure 4). The LTC6910-X’s logic is static (not latched)

and therefore lacks bus timing requirements. However, as

with any programmable-gain amplifier, each gain change

causes an output transient as the amplifier’s output

moves, with finite speed, toward a differently scaled ver-

sion of the input signal. Varying the gain faster than the

output can settle produces a garbled output signal. The

LTC6910-X analog path settles with a characteristic time

constant or time scale, τ, that is roughly the standard

value for a first order band limited response:

τ = 1 / (2 π f-3dB),

where f-3dB is the –3dB bandwidth of the amplifier. For

example, when the upper –3dB frequency is 1MHz, τ

is about 160ns. The bandwidth, and therefore τ, varies

with gain (see Frequency Response and –3dB Bandwidth

curves in Typical Performance Characteristics). After a

gain change it is the new gain value that determines the

settling time constant. Exact settling timing depends on

the gain change, the input signal and the possibility of

slew limiting at the output. However as a basic guideline,

the range of τ is 20ns to 1400ns for the LTC6910-1, 20ns

to 900ns for the LTC6910-2 and 20ns to 120ns for the

LTC6910-3. These numbers correspond to the ranges of

–3dB Bandwidth in the plots of that title under Typical

Performance Characteristics.

Offset Voltage vs Gain Setting

The electrical tables list DC offset (error) voltage at the

inputs of the internal op-amp in Figure 4, VOS(OA), which

is the source of DC offsets in the LTC6910-X. The tables

also show the resulting, gain dependent offset voltage

referred to the IN pin, VOS(IN). These two measures are

related through the feedback/input resistor ratio, which

equals the nominal gain-magnitude setting, G:

VOS(IN) = (1 + 1/G) VOS(OA)

Offset voltages at any gain setting can be inferred from

this relationship. For example, an internal offset VOS(OA)

of 1mV will appear referred to the IN pin as 2mV at a gain

setting G of 1, or 1.5mV at a gain setting of 2. At high

gains, VOS(IN) approaches VOS(OA). (Offset voltage can

be of either polarity; it is a statistical parameter centered

on zero.) The MOS input circuitry of the internal op amp

in Figure 4 draws negligible input currents (unlike some

op amps), so only VOS(OA) and G affect the overall ampli-

fier’s offset.

applicaTions inForMaTion

LTC6910-1/

LTC6910-2/LTC6910-3

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applicaTions inForMaTion

VCC 5V

1µF

500Ω

6910 F05b

AGND

LTC6910-X

17.4k

Figure 5a. Offset Nulling

(Dual Supplies)

49.9k

≥1µF

ANALOG GROUND

REFERENCE

20k

6910 F05a

AGND

–VREF

+VREF

LTC6910-X

Figure 5b. Offset Nulling

(Single Supply, Half Supply Reference)

Figure 5c. Offset Nulling

(Single Supply, External Reference)

VCC 5V VCC 5V

1.25V

SYSTEM DC REFERENCE

VOLTAGE

1µF

500Ω

6910 F05c

AGND

LTC6910-X

976Ω

4.64k R1

100Ω

Offset Nulling and Drift

Because internal op amp offset voltage V

OS(OA)

is gain

independent as noted above, offset trimming can be read-

ily added at the AGND pin, which drives the noninvert-

ing input of the internal op amp. Such a trim shifts the

AGND voltage slightly from the system’s analog ground

reference, where AGND would otherwise connect directly.

This is convenient when a low resistance analog ground

potential or analog ground reference exists, for the return

of a voltage divider as in Figure 5a. When adjusted for

zero DC output voltage when the LTC6910-X has zero

DC input voltage, this DC nulling will hold at other gain

settings also.

Figure 5a shows the basic arrangement for dual-supply

applications. A voltage divider (R1 and R2) scales external

reference voltages +VREF and –VREF to a range equaling

or slightly exceeding the approximately ±10mV op amp

offset-voltage range. Resistor R1 is chosen to drop the

±10mV maximum trim voltage when the potentiometer

is set to either end. Thus if VREF is 5V, R1 should be

about 100Ω. Note also that the two internal 10k resistors

in Figure 4 tend to bias AGND toward the mid-point of

V+ and V–. The external voltage divider will swamp this

effect if R1 is much less than 5kΩ. When considering the

effect of the internal 10k resistors, note that they form a

Thévenin equivalent of 5k in series with an open-circuit

voltage at the halfway potential (V+ + V–)/ 2. (Although

tightly matched, these internal 10k resistors also have

an absolute tolerance of up to ±30% and a temperature

coefficient of typically –30ppm/°C.) Also, as described

under Pin Functions for AGND, a bypass capacitor C1 is

always advisable when AGND is not connected directly

to a ground plane.

With this trim technique in place, the remaining DC off-

set sources are drifts with temperature (typically 6µV/°C

referred to VOS(OA)), shifts in the LTC6910-X’s supply

voltage divided by the PSRR factors, supply voltage

shifts coupling through the two 10k internal resistors of

Figure 4, and of course any shifts in the reference voltages

that supply +VREF and –VREF in Figure 5a.

Figure 5b illustrates how to make an offset voltage adjust-

ment relative to the mid-supply potential in single supply

applications. Resistor values shown provide at least a

±10mV adjustment range assuming the minimum values

for the internal resistors at pin 2 and a supply potential

of 5V. For single supply systems where all circuitry is DC

referenced to some other fixed bias potential, an offset

adjustment scheme is shown in Figure 5c. A low value

for R1 overrides the internal resistors at pin 2 and applies

the system DC bias to the LTC6910. Actual values for

the adjustment components depend on the magnitude of

the DC bias voltage. Offset adjustment component values

shown are an example with a single 5V VCC supply and a

1.25V system DC reference voltage.

LTC6910-1/

LTC6910-2/LTC6910-3

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applicaTions inForMaTion

Analog Input and DC Levels

As described in Tables 1, 2 and 3 and under Pin Functions,

the IN pin presents a variable input resistance returned

internally to a potential equal to that at the AGND pin

(within a small offset-voltage error). This input resistance

varies with digital gain setting, becoming infinite (open

circuit) at “zero” gain (digital input 000), and as low as

1kΩ at high gain settings. It is important to allow for this

input-resistance variation with gain, when driving

the LTC6910-X from other circuitry. Also, as the gain

increases above unity, the DC linear input-voltage range

(corresponding to rail-to-rail swing at the OUT pin) shrinks

toward the AGND potential. The output swings positive

or negative around the AGND potential (in the opposite

direction from the input, because the gain is inverting).

AC-Coupled Operation

Adding a capacitor in series with the IN pin makes the

LTC6910-X into an AC-coupled amplifier, suppressing the

source’s DC level (and even minimizing the offset voltage

from the LTC6910-X itself). No further components are

required because the input of the LTC6910-X biases itself

correctly when a series capacitor is added. The IN pin

connects to an internal variable resistor (and floats when

DC open-circuited to a well defined voltage equal to the

AGND input voltage at nonzero gain settings). The value

of this internal input resistor varies with gain setting over

a total range of about 1k to 10k, depending on version

(the rightmost columns of Table 1, Table 2 and Table 3).

Therefore, with a series input capacitor the low frequency

cutoff will also vary with gain. For example, for a low

frequency corner of 1kHz or lower, use a series capacitor

of 0.16µF or larger. A 0.16µF capacitor has a reactance

of 1kΩ at 1kHz, giving a 1kHz lower –3dB frequency for

gain settings of 10V/V through 100V/V in the LTC6910-1.

If the LTC6910-1 is operated at lower gain settings with

an 0.16µF input capacitor, the higher input resistance will

reduce the lower corner frequency down to 100Hz at a

gain setting of 1V/V. These frequencies scale inversely

with the value of the input capacitor.

Note that operating the LTC6910-X in zero gain mode (dig-

ital inputs 000) open circuits the IN pin and this demands

some care if employed with a series input capacitor. When

the chip enters the zero gain mode, the opened IN pin

tends to freeze the voltage across the capacitor to the

value it held just before the zero gain state. This can place

the IN pin at or near the DC potential of a supply rail

(the IN pin may also drift to a supply potential in this

state due to small junction leakage currents). To prevent

driving the IN pin outside the supply limit and potentially

damaging the chip, avoid AC input signals in the zero

gain state with a series capacitor. Also, switching later to

a nonzero gain value will cause a transient pulse at the

output of the LTC6910-X (with a time constant set by

the capacitor value and the new LTC6910-X input resis-

tance value). This occurs because the IN pin returns to

the AGND potential and transient current flows to charge

the capacitor to a new DC drop.

SNR and Dynamic Range

The term “dynamic range” is much used (and abused)

with signal paths. Signal-to-noise ratio (SNR) is an unam-

biguous comparison of signal and noise levels, measured

in the same way and under the same operating conditions.

In a variable gain amplifier, however, further characteriza-

tion is useful because both noise and maximum signal

level in the amplifier will vary with the gain setting, in

general. In the LTC6910-X, maximum output signal is

independent of gain (and is near the full power supply

voltage, as detailed in the Swing sections of the Electrical

Characteristics table). The maximum input level falls with

increasing gain, and the input-referred noise falls as well

(as listed also in the table). To summarize the useful signal

range in such an amplifier, we define Dynamic Range (DR)

as the ratio of maximum input (at unity gain) to mini-

mum input-referred noise (at maximum gain). (These two

numbers are measured commensurately, in RMS Volts.

For deterministic signals such as sinusoids, 1VRMS =

2.828VP-P.) This DR has a physical interpretation as the

range of signal levels that will experience an SNR above

unity V/V or 0dB. At a 10V total power supply, DR in the

LTC6910-1/

LTC6910-2/LTC6910-3

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1499Ω

270pF

LTC1864

VIN

AGND

GAIN

CONTROL

1µF

6910 F04

LTC6910-X

0.1µF

1µF

ADC

CONTROL

VREF

IN+

IN–

GND

VCC

SCK

SDO

CONV

Figure 6. Expanding an ADC’s Dynamic Range

LTC6910-1 (gains 0V to 100V/V) is typically 120dB (the

ratio of a nominal 9.9V

P-P

, or 3.5V

RMS

, maximum input to

the 3.4µVRMS high gain input noise). The corresponding

DR for the LTC6910-2 (gains 0V to 64V) is also 120dB;

for the LTC6910-3 (gains 0V to 7V/V) it is 117dB. The

SNR from an amplifier is the ratio of input level to input-

referred noise, and can be 110dB with the LTC6910 family

at unity gain.

Construction and Instrumentation Cautions

Electrically clean construction is important in applica-

tions seeking the full dynamic range of the LTC6910-X

amplifier. Short, direct wiring will minimize parasitic

capacitance and inductance. High quality supply bypass

capacitors of 0.1µF near the chip provide good decou-

pling from a clean, low inductance power source. But

several cm of wire (i.e., a few microhenrys of inductance)

from the power supplies, unless decoupled by substantial

capacitance (≥10µF) near the chip, can cause a high-Q

LC resonance in the hundreds of kHz in the chip’s sup-

plies or ground reference. This may impair circuit perfor-

mance at those frequencies. A compact, carefully laid out

printed circuit board with a good ground plane makes a

significant difference in minimizing distortion. Finally,

equipment to measure amplifier performance can itself

introduce distortion or noise floors. Checking for these

limits with a wire replacing the chip is a prudent routine

procedure.

Expanding an ADC’s Dynamic Range

Figure 6 shows a compact data acquisition system

for wide ranging input levels. This figure combines an

LTC6910-X programmable amplifier (8-lead TSOT-23)

with an LTC1864 analog-to-digital converter (ADC) in

an 8-lead MSOP. This ADC has 16-bit resolution and a

maximum sampling rate of 250ksps. An LTC6910-1, for

example, expands the ADC’s input amplitude range by

40dB while operating from the same single 5V supply.

The 499Ω resistor and 270pF capacitor couple cleanly

between the LTC6910-X’s output and the switched-capac-

itor input of the LTC1864. The 270pF capacitor should be

an NPO or X7R type, and lead length and inductance in the

connections to the LTC1864 inputs must be minimized,

to achieve the full performance capability of this circuit.

(See LTC 1864 data sheet for further general information.)

At a gain setting of 10V/V in an LTC6910-1 (digital input

100) and a 250ksps sampling rate in the LTC1864, a

10kHz input signal at 60% of full scale shows a THD of

–87dB at the digital output of the ADC. 100kHz input

signals under the same conditions produce THD values

around –75dB. Noise effects (both random and quantiza-

tion) in the ADC are divided by the gain of the amplifier

when referred to VIN in Figure 4. Because of this, the

circuit can acquire a signal that is 40dB down from full

scale of 5VP-P with an SNR of over 70dB. Such perfor-

mance from an ADC alone (70 + 40 = 110dB of useful

dynamic range at 250ksps), if available, would be far more

expensive.

applicaTions inForMaTion

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

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–

+–

–

VIN C1

GAIN CONTROL PGA

(GAIN A)

VOUT = (GAIN A)VIN

BANDWIDTH CONTROL PGA

(GAIN B) GAIN = –1

VOUT

6910 F05

2πR1C1 BANDWIDTH 1

(GAIN B)

2π C2

Figure 7. Block Diagram of an AC Amplifier with Programmable Gain and Bandwidth

Low Noise AC Amplifier with Programmable Gain

and Bandwidth

Analog data acquisition can exploit band limiting as well

as gain to suppress unwanted signals or noise. Tailoring

an analog front end to both the level and bandwidth of

each source maximizes the resulting SNR.

Figure 7 shows a block diagram and Figure 8 the practical

circuit for a low noise amplifier with gain and bandwidth

independently programmable over 100:1 ranges. One

LTC6910-X controls the gain and another controls the

bandwidth. An LT1884 dual op amp forms an integrating

lowpass loop with capacitor C2 to set the programmable

upper corner frequency. The LT1884 also supports rail-

to-rail output swings over the total supply voltage range

of 2.7V to 10.5V. AC coupling through capacitor C1

establishes a fixed low frequency corner of 1Hz, which

can be adjusted by changing C1. Alternatively, shorting

C1 makes the amplifier DC coupled. (If DC gain is not

needed, however, the AC coupling suppresses several

error sources: any shifts in DC levels, low frequency

noise and all amplifier DC offset voltages other than the

low internally trimmed LT1884 offset in the integrating

amplifier. If desired, another coupling capacitor in series

with the input can relax the requirements on DC input

level as well.)

applicaTions inForMaTion

LTC6910-1/

LTC6910-2/LTC6910-3

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–

V–

VOUT

R4 15.8k

V–

V+

LT1884

1µF

10µF R1

15.8k

VIN

15.8k

0.1µF

GN2 GN1 GN0

0 0 1 GAIN = 1

0 1 0 GAIN = 2

0 1 1 GAIN = 5

1 0 0 GAIN = 10

1 0 1 GAIN = 20

1 1 0 GAIN = 50

1 1 1 GAIN = 100

BW2 BW1 BW0

BANDWIDTH 1Hz TO 10Hz 0 0 1

BANDWIDTH 1Hz TO 20Hz 0 1 0

BANDWIDTH 1Hz TO 50Hz 0 1 1

BANDWIDTH 1Hz TO 100Hz 1 0 0

BANDWIDTH 1Hz TO 200Hz 1 0 1

BANDWIDTH 1Hz TO 500Hz 1 1 0

BANDWIDTH 1Hz TO 1000Hz 1 1 1

0.1µF 0.1µF

V+V–

427

0.1µF

0.1µF 0.1µF

V+V–

LTC6910-1 LTC6910-1

15.8k

BANDWIDTH

CONTROL

GAIN

CONTROL

FREQUENCY (Hz)

–60

GAIN (dB)

–50

–30

–20

1 100 1k

100k

6910 F06b

–70

10 10k

–10

–40

–80

GN2 GN1 GN0 = 001

BW2

BW1

BW0

BW2

BW1

BW0

BW2

BW1

BW0

Gain vs Frequency

Figure 8. Low Noise AC Amplifier with Programmable Gain and Bandwidth

Measured frequency responses in Figure 8 with

LTC6910-1 PGAs demonstrate bandwidth settings of

10Hz, 100Hz and 1kHz, with digital codes at the BW inputs

of respectively 001, 100 and 111, and unity gain in each

case. By scaling C2, this circuit can serve other band-

widths, such as a maximum of 10kHz with 0.1µF using

LT1884 (gain-bandwidth product around 1MHz). Noise

floor from internal sources yields an output SNR of 76dB

with 10mVP-P input, gain of 100 and 100Hz bandwidth;

for 100mVP-P input, gain of 10 and 1000Hz bandwidth it

is 64dB.

applicaTions inForMaTion

LTC6910-1/

LTC6910-2/LTC6910-3

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package DescripTion

TS8 Package

8-Lead Plastic TSOT-23

(Reference LTC DWG # 05-08-1637 Rev A)

Please refer to http://www.linear.com/product/LTC6910#packaging for the most recent package drawings.

1.50 – 1.75

(NOTE 4)

2.80 BSC

0.22 – 0.36

8 PLCS (NOTE 3)

DATUM ‘A’

0.09 – 0.20

(NOTE 3)

TS8 TSOT-23 0710 REV A

2.90 BSC

(NOTE 4)

0.65 BSC

1.95 BSC

0.80 – 0.90

1.00 MAX 0.01 – 0.10

0.20 BSC

0.30 – 0.50 REF

PIN ONE ID

NOTE:

1. DIMENSIONS ARE IN MILLIMETERS

2. DRAWING NOT TO SCALE

3. DIMENSIONS ARE INCLUSIVE OF PLATING

4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR

5. MOLD FLASH SHALL NOT EXCEED 0.254mm

6. JEDEC PACKAGE REFERENCE IS MO-193

3.85 MAX

0.40

MAX

0.65

REF

RECOMMENDED SOLDER PAD LAYOUT

PER IPC CALCULATOR

1.4 MIN

2.62 REF

1.22 REF

TS8 Package

8-Lead Plastic TSOT-23

(Reference LTC DWG # 05-08-1637 Rev A)

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

revision hisTory

REV DATE DESCRIPTION PAGE NUMBER

B 06/17 Updated Voltage Gain Specs 6, 8

(Revision history begins at Rev B)

LTC6910-1/

LTC6910-2/LTC6910-3

6910123fb

For more information www.linear.com/LTC6910

 LINEAR TECHNOLOGY CORPORATION 2002

LT 0617 REV B • PRINTED IN USA

www.linear.com/LTC6910

relaTeD parTs

Typical applicaTion

PART NUMBER DESCRIPTION COMMENTS

1228 100MHz Gain Controlled Transconductance Amplifier Differential Input, Continuous Analog Gain Control

LT1251/LT1256 40MHz Video Fader and Gain Controlled Amplifier Two Input, One Output, Continuous Analog Gain Control

LTC1564 10kHz to 150kHz Digitally Controlled Filter and PGA Continuous Time, Low Noise 8th Order Filter and 4-Bit PGA

LTC6911 Dual Matched Programmable Gain Amplifier Dual 6910 in a 10 Lead MSOP

LTC6915 Zero Drift Instrumentation Amplifier with Programmable Gain Zero Drift, Digitally Programmable Gain Up to 4096 V/V

VIN VOUT = GAIN • VIN

AGND

1µF OR LARGER

PIN 2 (AGND) SETS DC OUTPUT VOLTAGE AND HAS

BUILT-IN HALF-SUPPLY REFERENCE WITH INTERNAL

RESISTANCE OF 5k. AGND CAN ALSO BE DRIVEN BY A

SYSTEM ANALOG GROUND REFERENCE NEAR HALF SUPPLY

C1 VALUE SETS LOWER CORNER FREQUENCY.

THE TABLE SHOWS THIS FREQUENCY WITH

C1 = 1µF. THIS FREQUENCY SCALES INVERSELY

WITH C1

6910 TA02

LTC6910-X

V+

2.7V TO 10.5V

0.1µF

G2 G1 G0

–1

–2

–5

–10

–20

–50

–100

–1

–2

–4

–8

–16

–32

–64

LTC6910-1 LTC6910-2 LTC6910-3

–1

–2

–3

–4

–5

–6

–7

PASSBAND

GAIN

PASSBAND

GAIN

PASSBAND

GAIN

LOWER –3dB

FREQ (C1 = 1µF)

LOWER –3dB

FREQ (C1 = 1µF)

LOWER –3dB

FREQ (C1 = 1µF)

—

16Hz

32Hz

80Hz

160Hz

—

16Hz

32Hz

64Hz

127Hz

—

16Hz

32Hz

48Hz

64Hz

80Hz

95Hz

111Hz

DIGITAL INPUTS

G2 G1 G0

AC-Coupled Single Supply Amplifiers

Frequency Response, LTC6910-1

FREQUENCY (Hz)

100

–10

GAIN (dB)

1k 10k 100k 1M

6910 TA03

G2, G1, G0 = 111

G2, G1, G0 = 110

G2, G1, G0 = 101

G2, G1, G0 = 100

G2, G1, G0 = 011

G2, G1, G0 = 010

G2, G1, G0 = 001

VS = 10V, VIN = 5mVRMS

C1 = 1µF

Frequency Response, LTC6910-2

FREQUENCY (Hz)

100

–10

GAIN (dB)

1k 10k 100k 1M

6910 TA04

VS = 10V, VIN = 5mVRMS

C1 = 1µF

G2, G1, G0 = 111

G2, G1, G0 = 110

G2, G1, G0 = 101

G2, G1, G0 = 100

G2, G1, G0 = 011

G2, G1, G0 = 010

G2, G1, G0 = 001

Frequency Response, LTC6910-3

FREQUENCY (Hz)

10 100

–10

GAIN (dB)

–5

1k 10k 100k

10M

6910 TA05

G2, G1, G0 = 111 G2, G1, G0 = 110

G2, G1, G0 = 101

G2, G1, G0 = 100

G2, G1, G0 = 011

G2, G1, G0 = 010

G2, G1, G0 = 001

VS = 10V

VIN = 10mVRMS

C1 = 1µF