MIC7122YMM - Mitsubishi Electric Semiconductor

January 2005 1 MIC7122

MIC7122 MicrelMIC7122 Micrel

MIC7122

Rail-to-Rail Dual Op Amp

Final Information

General Description

The MIC7122 is a dual high-performance CMOS operational

amplifier featuring rail-to-rail inputs and outputs.

The input common-mode range extends beyond the rails by

300mV, and the output voltage swings to within 150µV of

both rails when driving a 100kΩ load.

The amplifiers operate from 2.2V to 15V and are fully

specified at 2.2V, 5V, and 15V. Gain bandwidth and slew

rate are 750kHz and 0.7V/µs, respectively at 2.2V supply.

The MIC7122 is available in the MM8™ 8-lead MSOP

package.

Features

•Small footprint MSOP-8 package

• 350µA supply current per op amp at 2.2V supply

•Guaranteed 2.2V, 5V, and 15V performance

•750kHz gain-bandwidth product at 2.2V supply

•0.01% total harmonic distortion at 1kHz (15V, 2kΩ)

•Drives 200pF at 5V and greater supply voltages

Applications

•Battery-powered instrumentation

•PCMCIA, USB peripherals

•Portable computers and PDAs

Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com

MM8 is a trademark of Micrel, Inc.

Pin Description

Pin Number Pin Name Pin Function

1 / 7 OUTA / OUTB Amplifier Outputs

2 / 6 INA– / INB– Inverting Inputs

3 / 5 INA+ / INB+ Noninverting Inputs

4V–Negative Supply: Negative supply for split supply application or ground for

single supply applications.

8V+Positive Supply

Pin Configuration

V+

OUT B

INB–

INB+

OUT A

IN A–

IN A+

V–

MSOP-8 (MM)

Ordering Information

Part Number

Standard Pb-free Temperature Range Package

MIC7122BMM MIC7122YMM –40°C to +85°CMSOP-8

MIC7122 Micrel

MIC7122 2 January 2005

Absolute Maximum Ratings (Note 1)

Supply Voltage (VV+ – VV–) ........................................ 16.5V

Differential Input Voltage (VIN+ – VIN–) .......................±10V

I/O Pin Voltage (VIN, VOUT), Note 3

............................................. VV+ + 0.3V to VV– – 0.3V

Junction Temperature (TJ) ...................................... +150°C

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

Lead Temperature (soldering, 10 sec.) ..................... 260°C

ESD, Note 6 .............................................................. 1000V

Operating Ratings (Note 2)

Supply Voltage (VV+ – VV–).............................. 2.2V to 15V

Junction Temperature (TJ) ......................... –40°C to +85°C

Max. Junction Temperature (TJ(max)), Note 4 ......... +125°C

Max. Power Dissipation............................................ Note 4

Package Thermal Resistance, Note 5

MSOP-8 (θJA) .................................................... 200°C/W

DC Electrical Characteristics (2.2V)

VV+ = +2.2V, VV– = 0V, VCM = VOUT = VV+/2; RL = 1MΩ; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C

; Note 7

; unless noted

Symbol Parameter Condition Min Typ Max Units

VOS Input Offset Voltage 0.5 9 mV

TCVOS Input Offset Voltage Average Drift 3.0 µV/°C

IBInput Bias Current 1.0 10 pA

64 500 pA

IOS Input Offset Current 0.5 5 pA

32 250 pA

RIN Input Resistance >1 TΩ

CMRR Common-Mode Rejection Ratio -0.3V ≤ VCM ≤ 2.5V, Note 9 45 65 dB

±PSRR Power Supply Rejection Ratio VV+ = VV– = 1.1V to 2.5V, VOUT = VCM = 0 60 85 dB

CIN Common-Mode Input Capacitance 3 pF

VOOutput Swing output high, RL = 100k, 0.15 1 mV

specified as VV+ – VOUT 1mV

output low, RL = 100k 0.15 1 mV

1mV

output high, RL = 2k 8 33 mV

specified as VV+ – VOUT 50 mV

output low, RL = 2k 8 33 mV

50 mV

output high, RL = 600Ω26 110 mV

specified as VV+ – VOUT 165 mV

output low, RL = 600Ω26 110 mV

165 mV

ISC Output Short Circuit Current sinking or sourcing, Note 8 20 50 mA

ISSupply Current both amplifiers 0.7 1.6 mA

AC Electrical Characteristics (2.2V)

VV+ = 2.2V, VV– = 0V, VCM = VOUT = VV+/2; RL = 1MΩ; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C

; Note 7

; unless noted

Symbol Parameter Condition Min Typ Max Units

SR Slew Rate 0.7 V/µs

GBW Gain-Bandwidth Product 750 kHz

φmPhase Margin CL = 0pF 80 °

CL = 200pF 40 °

GmGain Margin 10 dB

Interamplifier Isolation Note 12 90 dB

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DC Electrical Characteristics (5V)

V+

= +5.0V, V

V–

= 0V, V

= 1.5V, V

OUT

= V

V+

/2; R

= 1MΩ; T

= 25°C, bold values indicate –40°C ≤ T

≤ +85°C; Note 7; unless noted

Symbol Parameter Condition Min Typ Max Units

VOS Input Offset Voltage 0.5 9 mV

TCVOS Input Offset Voltage Average Drift 3.0 µV/°C

IBInput Bias Current 1.0 10 pA

64 500 pA

IOS Input Offset Current 0.5 5 pA

32 250 pA

RIN Input Resistance >1 TΩ

CMRR Common-Mode Rejection Ratio -0.3V ≤ VCM ≤ 5.3V, Note 9 55 75 dB

±PSRR Power Supply Rejection Ratio VV+ = VV– = 2.5V to 7.5V, VOUT = VCM = 0 55 100 dB

CIN Common-Mode Input Capacitance 3 pF

VOUT Output Swing output high, RL = 100k 0.3 1.0 mV

specified as VV+ – VOUT 1.5 mV

output low, RL = 100k 0.3 1.0 mV

1.5 mV

output high, RL = 2k 13 50 mV

specified as VV+ – VOUT 75 mV

output low, RL = 2k 13 50 mV

75 mV

output high, RL = 600Ω40 165 mV

specified as VV+ – VOUT 250 mV

output low, RL = 600Ω40 165 mV

250 mV

ISC Output Short Circuit Current sinking or sourcing, Note 8 40 140 mA

ISSupply Current both amplifiers 0.8 1.8 mA

AC Electrical Characteristics (5V)

VV+ = 5V, VV– = 0V, VCM = 1.5V, VOUT = VV+/2; RL = 1MΩ; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C

; Note 7

; unless noted

Symbol Parameter Condition Min Typ Max Units

THD Total Harmonic Distortion f = 1kHz, AV = –2, 0.05 %

RL = 2kΩ, VOUT = 4.0 VPP

SR Slew Rate 0.6 V/µs

GBW Gain-Bandwidth Product 465 kHz

φmPhase Margin CL = 0pF 85 °

CL = 200pF 40 °

GmGain Margin 10 dB

Interamplifier Isolation Note 12 90 dB

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MIC7122 4 January 2005

DC Electrical Characteristics (15V)

V+

= +15V, V

V–

= 0V, V

= 1.5V, V

OUT

= V

V+

/2; R

= 1MΩ; T

= 25°C, bold values indicate –40°C ≤ T

≤ +85°C; Note 7; unless noted

Symbol Parameter Condition Min Typ Max Units

VOS Input Offset Voltage 0.5 9 mV

TCVOS Input Offset Voltage Average Drift 3.0 µV/°C

IBInput Bias Current 1.0 10 pA

64 500 pA

IOS Input Offset Current 0.5 5 pA

32 250 pA

RIN Input Resistance >1 TΩ

CMRR Common-Mode Rejection Ratio -0.3V ≤ VCM ≤ 15.3V, Note 9 60 85 dB

±PSRR Power Supply Rejection Ratio VV+ = VV– = 2.5V to 7.5V, VOUT = VCM = 0 55 100 dB

AVLarge Signal Voltage Gain sourcing or sinking, 340 V/mV

RL = 2k, Note 10

sourcing or sinking, 300 V/mV

RL = 600Ω, Note 10

CIN Common-Mode Input Capacitance 3 pF

VOUT Output Swing output high, RL = 100k 0.8 2 mV

specified as VV+ – VOUT 3mV

output low, RL = 100k 0.8 2 mV

3mV

output high, RL = 2k 40 80 mV

specified as VV+ – VOUT 120 mV

output low, RL = 2k 40 80 mV

120 mV

output high, RL = 600Ω130 270 mV

specified as VV+ – VOUT 400 mV

output low, RL = 600Ω130 270 mV

400 mV

ISC Output Short Circuit Current sinking or sourcing, Notes 8 50 250 mA

ISSupply Current both amplifiers 0.9 2.0 mA

AC Electrical Characteristics (15V)

VV+ = 15V, VV– = 0V, VCM = 1.5V, VOUT = VV+/2; RL = 1MΩ; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C

; Note 7

; unless noted

Symbol Parameter Condition Min Typ Max Units

THD Total Harmonic Distortion f = 1kHz, AV = –2, 0.01 %

RL = 2k, VOUT = 8.5 VPP

SR Slew Rate V+ = 15V, Note 11 0.5 V/µs

GBW Gain-Bandwidth Product 420 kHz

φmPhase Margin CL = 0pF 85 °

CL = 500pF 40 °

GmGain Margin 10 dB

enInput-Referred Voltage Noise f = 1kHz, VCM = 1V 37 nV/ Hz

inInput-Referred Current Noise f = 1kHz 1.5

fA/ Hz

Interamplifier Isolation Note 12 90 dB

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Note 1. Exceeding the absolute maximum rating may damage the device.

Note 2. The device is not guaranteed to function outside its operating rating.

Note 3. I/O Pin Voltage is any external voltage to which an input or output is referenced.

Note 4. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max); the junction-to-ambient thermal

resistance, θJA; and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using:

PD = (TJ(max) – TA) ÷ θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature.

Note 5. Thermal resistance, θJA, applies to a part soldered on a printed-circuit board.

Note 6. Devices are ESD protected; however, handling precautions are recommended. Human body model, 1.5kΩ in series with 100pF.

Note 7. All limits guaranteed by testing or statistical analysis.

Note 8. Continuous short circuit may exceed absolute maximum TJ under some conditions.

Note 9. CMRR is determined as follows: The maximum ∆VOS over the VCM range is divided by the magnitude of the VCM range. The measurement

points are: VCM = VV– – 0.3V, (VV+ – VV–)/2, and VV+ + 0.3V.

Note 10. RL connected to 7.5V. Sourcing: 7.5V ≤ VOUT ≤ 12.5V. Sinking: 2.5V ≤ VOUT ≤ 7.5V.

Note 11. Device connected as a voltage follower with a 10V step input. The value is the positive or negative slew rate, whichever is slower.

Note 12. Referenced to input.

MIC7122 Micrel

MIC7122 6 January 2005

Application Information

Input Common-Mode Voltage

The MIC7122 tolerates input overdrive by at least 300mV

beyond either rail without producing phase inversion.

If the absolute maximum input voltage is exceeded, the input

current should be limited to ±5mA maximum to prevent

reducing reliability. A 10kΩ series input resistor, used as a

current limiter, will protect the input structure from voltages as

large as 50V above the supply or below ground. See Figure

OUT

10kΩ

Figure 1. Input Current-Limit Protection

Output Voltage Swing

Sink and source output resistances of the MIC7122 are

equal. Maximum output voltage swing is determined by the

load and the approximate output resistance. The output

resistance is:

OUT DROP

LOAD

VDROP is the voltage dropped within the amplifier output

stage. VDROP and ILOAD can be determined from the VO

(output swing) portion of the appropriate Electrical Character-

istics table. ILOAD is equal to the typical output high voltage

minus V+/2 and divided by RLOAD. For example, using the

Electrical Characteristics DC (5V) table, the typical output

high voltage drops 13mV using a 2kΩ load (connected to V+/

2), which produces an ILOAD of:

Because of output stage symmetry, the corresponding typical

output low voltage (13mV) also equals VDROP. Then:

Power Dissipation

The MIC7122 output drive capability requires considering

power dissipation. If the load impedance is low, it is possible

to damage the device by exceeding the 125°C junction

temperature rating.

On-chip power consists of two components: supply power

and output stage power. Supply power (PS) is the product of

the supply voltage (VS = VV+ – VV–) and supply current (IS).

Output stage power (PO) is the product of the output stage

voltage drop (VDROP) and the output (load) current (IOUT).

Total on-chip power dissipation is:

PD = PS + PO

PD = VSIS + VDROP IOUT

where:

PD = total on-chip power

PS = supply power dissipation

PO = output power dissipation

VS = VV+ – VV–

IS = power supply current

VDROP = VV+ – VOUT (sourcing current)

VDROP = VOUT – VV– (sinking current)

The above addresses only steady state (dc) conditions. For

non-dc conditions the user must estimate power dissipation

based on rms value of the signal.

The task is one of determining the allowable on-chip power

dissipation for operation at a given ambient temperature and

power supply voltage. From this determination, one may

calculate the maximum allowable power dissipation and,

after subtracting PS, determine the maximum allowable load

current, which in turn can be used to determine the miniumum

load impedance that may safely be driven. The calculation is

summarized below.

PTT

D(max)

J(max) A

=−

θJA(MSOP-8) = 200°C/W

Driving Capacitive Loads

Driving a capacitive load introduces phase-lag into the output

signal, and this in turn reduces op-amp system phase margin.

The application that is least forgiving of reduced phase

margin is a unity gain amplifier. The MIC7122 can typically

drive a 200pF capacitive load connected directly to the output

when configured as a unity-gain amplifier and powered with

a 2.2V supply. At 15V operation the circuit typically drives

500pF.

Using Large-Value Feedback Resistors

A large-value feedback resistor (> 500kΩ) can reduce the

phase margin of a system. This occurs when the feedback

resistor acts in conjunction with input capacitance to create

phase lag in the feedback signal. Input capacitance is usually

a combination of input circuit components and other parasitic

capacitance, such as amplifier input capacitance and stray

printed circuit board capacitance.

Figure 2 illustrates a method of compensating phase lag

caused by using a large-value feedback resistor. Feedback

capacitor CFB introduces sufficient phase lead to overcome

the phase lag caused by feedback resistor RFB and input

5.0V – 0.013V – 2.5V

2k 1.244mA

Ω=

R0.013V

0.001244A

OUT ==10 5.Ω

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capacitance CIN. The value of CFB is determined by first

estimating CIN and then applying the following formula:

RIN × CIN ≤ RFB × CFB

VIN

CFB

RFB

VOUT

CIN

RIN

Figure 2. Cancelling Feedback Phase Lag

Since a significant percentage of CIN may be caused by board

layout, it is important to note that the correct value of CFB may

change when changing from a breadboard to the final circuit

layout.

Typical Circuits

Some single-supply, rail-to-rail applications for which the

MIC7122 is well suited are shown in the circuit diagrams of

Figures 3 through 7.

910k

100k

VOUT

0V to V+

V+

VIN

1⁄2 MIC7122

0V to V+

Figure 3a. Noninverting Amplifier

100

0100

VOUT (V)

VIN (V)

V+

V=+ ≈10

Figure 3b. Noninverting Amplifier Behavior

OUT

0V to V+

V+

0V to V+

⁄

MIC7122

OUT

= V

Figure 4. Voltage Follower/Buffer

OUT

0V to V+

V+

0V to 2V

⁄

MIC7122

10Ω

⁄

Load

0.5V to Q1 V

CEO(sus)

OUT

2N3904 V

CEO

= 40V

C(max)

= 200mA

{

Change Q1 and R

for higher current

and/or different gain.

R100mA/V as shown

OUT IN

Figure 5. Voltage-Controlled Current Sink

V+

100k

OUT

V+

⁄

MIC7122

0.001µF

100k

V+

Figure 6. Square Wave Oscillator

330k

33k

330k

1µF

VOUT

V+

1⁄2 MIC7122

V+

COUT

AR2

330k

33k 10

=−==−

Figure 7. AC-Coupled Inverting Amplifier

MIC7122 Micrel

MIC7122 8 January 2005

Package Information

0.008 (0.20)

0.004 (0.10)

0.039 (0.99)

0.035 (0.89)

0.021 (0.53)

0.012 (0.03) R

0.0256 (0.65) TYP

0.012 (0.30) R

5° MAX

0° MIN

0.122 (3.10)

0.112 (2.84)

0.120 (3.05)

0.116 (2.95)

0.012 (0.03)

0.007 (0.18)

0.005 (0.13)

0.043 (1.09)

0.038 (0.97)

0.036 (0.90)

0.032 (0.81)

DIMENSIONS:

INCH (MM)

0.199 (5.05)

0.187 (4.74)

MM8™ 8-Lead MSOP (MM)

MICREL INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA

TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com

This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or

other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel Inc.