ADS-916GC - Murata Power Solutions

Figure 1. ADS-926 Functional Block Diagram

REF

18 BIT 1 (MSB)

17 BIT 2

12 TIB 3

11 BIT 4

10 BIT 5

9 BIT 6

8 BIT 7

7 BIT 8

6 BIT 9

5 BIT 10

4 BIT 11

3 BIT 12

2 BIT 13

1 BIT 14 (LSB

)

TIMING AND

CONTROL LOGIC

+10V REF. OUT 21

START CONVERT 16

EOC 15

DIGITAL CORRECTION LOGIC

DAC

FLASH

ADC

BUFFER

–

S/H

ANALOG INPUT 20

+5V SUPPLY

+12V/+15V SUPPLY

19, 23

ANALOG GROUND

DIGITAL GROUND

–12V/–15V SUPPLY

BLOCK DIAGRAM

The ADS-926 is a high-performance, 14-bit,

500kHz sampling A/D converter. This device

accurately samples full-scale input signals up to

Nyquist frequencies with no missing codes and

exhibits outstanding dynamic performance that

surpasses most 16-bit, 500kHz sampling A/D's.

THD and SNR, for example, are typically –90dB

and 80dB when converting fullscale input signals

up to 100kHz.

Housed in a small 24-pin DDIP or SMT (gull-

wing) package, the functionally complete ADS-926

contains a fast-settling sample-hold ampliﬁ er, a

subranging (two-pass) A/D converter, a precise

voltage reference, timing/control logic, and error-

correction circuitry. Digital input and output levels

are TTL.

Requiring ±15V (or ±12V) and +5V supplies,

the ADS-926 dissipates only 1.75W (1.6W for

±12V), maximum. The unit is offered with a bipolar

input (–5V to +5V). Models are available for use in

either commercial (0 to +70°C) or military (–55 to

+125°C) operating temperature ranges.

Applications include radar, sonar, spectrum

analysis, and graphic/medical imaging. Contact

DATEL for information on devices screened to

MIL-STD-883.

PRODUCT OVERVIEW

FEATURES

■ 14-bit resolution

■ 500kHz sampling rate

■ Functionally complete; No missing codes

■ Small 24-pin DDIP or SMT package

■ Operates from ±15V or ±12V supplies

+5V supply

■ Low power, 1.75 Watts maximum

■ Samples up to Nyquist frequencies

■ Outstanding dynamic performance

■ Bipolar ±5V input range

INPUT/OUTPUT CONNECTIONS

PIN FUNCTION PIN FUNCTION

1 BIT 14 (LSB) 24 –12V/–15V SUPPLY

2 BIT 13 23 ANALOG GROUND

3 BIT 12 22 +12V/+15V SUPPLY

4 BIT 11 21 +10V REFERENCE OUT

5 BIT 10 20 ANALOG INPUT

6 BIT 9 19 ANALOG GROUND

7 BIT 8 18 BIT 1 (MSB)

8 BIT 7 17 BIT 2

9 BIT 6 16 START CONVERT

10 BIT 5 15 EOC

11 BIT 4 14 DIGITAL GROUND

12 BIT 3 13 +5V SUPPLY

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

01 Apr 2011 MDA_ADS-926.B02 Page 1 of 8

PHYSICAL/ENVIRONMENTAL

PARAMETERS MIN. TYP. MAX. UNITS

Operating Temp. Range, Case

ADS-926MC, GC 0 — +70 °C

ADS-926MM, GM –55 — +125 °C

Thermal Impedance

θjc — 6 — °C/Watt

θca — 24 — °C/Watt

Storage Temperature Range –65 — +150 °C

Package Type 24-pin, metal-sealed, ceramic DDIP or SMT

Weight 0.42 ounces (12 grams)

ABSOLUTE MAXIMUM RATINGS

PARAMETERS LIMITS UNITS

+12V/+15V Supply (Pin 22) 0 to +16 Volts

–12V/–15V Supply (Pin 24) 0 to –16 Volts

+5V Supply (Pin 13) 0 to +6 Volts

Digital Input (Pin 16) –0.3 to +VDD +0.3 Volts

Analog Input (Pin 20) ±15 Volts

Lead Temperature (10 seconds) +300 °C

+25°C 0 TO +70°C –55 TO +125°C

ANALOG INPUT MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS

Input Voltage Range ➁ — ±5 — — ±5 — — ±5 — Volts

Input Resistance — 1 — — 1 — — 1 — k

Input Capacitance — 7 15 — 7 15 — 7 15 pF

DIGITAL INPUT

Logic Levels

Logic "1" +2.0 — — +2.0 — — +2.0 — — Volts

Logic "0" — — +0.8 — — +0.8 — — +0.8 Volts

Logic Loading "1" — — +20 — — +20 — — +20 µA

Logic Loading "0" — — –20 — — –20 — — –20 µA

Start Convert Positive Pulse Width ➂ 175 200 225 175 200 225 175 200 225 ns

STATIC PERFORMANCE

Resolution — 14 — — 14 — — 14 — Bits

Integral Nonlinearity (fin = 10kHz) — ±0.5 — — ±0.75 — — ±1.5 — LSB

Differential Nonlinearity (fin = 10kHz) — ±0.5 +0.95 — ±0.5 ±0.95 — ±0.75 +0.99 LSB

Full Scale Absolute Accuracy — ±0.08 ±0.15 — ±0.15 ±0.25 — ±0.3 ±0.5 %FSR

Bipolar Zero Error (Tech Note 2) — ±0.05 ±0.1 — ±0.1 ±0.25 — ±0.15 ±0.3 %FSR

Bipolar Offset Error (Tech Note 2) — ±0.05 ±0.1 — ±0.1 ±0.25 — ±0.25 ±0.5 %FSR

Gain Error (Tech Note 2) — ±0.1 ±0.15 — ±0.15 ±0.25 — ±0.25 ±0.5 %FSR

No Missing Codes (fin = 10kHz) 14 — — 14 — — 14 — — Bits

DYNAMIC PERFORMANCE

Peak Harmonics (–0.5dB)

dc to 100kHz — –92 –88 — –90 –85 — –88 –81 dB

100kHz to 250kHz — –90 –85 — –90 –85 — –86 –80 dB

Total Harmonic Distortion (–0.5dB)

dc to 100kHz — –90 –86 — –89 –82 — –87 –78 dB

100kHz to 250kHz — –87 –82 — –87 –82 — –81 –76 dB

Signal-to-Noise Ratio

(w/o distortion, –0.5dB)

dc to 100kHz 78 80 — 78 80 — 74 78 — dB

100kHz to 250kHz 78 80 — 78 80 — 74 77 — dB

Signal-to-Noise Ratio ➃

(& distortion, –0.5dB)

dc to 100kHz 77 79 — 77 79 — 74 78 — dB

100kHz to 250kHz 77 79 — 77 79 — 73 77 — dB

Two-tone Intermodulation

Distortion (fin = 100kHz,

240kHz, fs = 500kHz –0.5dB) — –87 — — –86 — — –85 — dB

Noise — 300 — — 300 — — 350 — µVrms

Input Bandwidth (–3dB)

Small Signal (–20dB input) — 7 — — 7 — — 7 — MHz

Large Signal (–0.5dB input) — 3 — — 3 — — 3 — MHz

Feedthrough Rejection (fin = 250kHz) — 84 — — 84 — — 84 — dB

Slew Rate — ±40 — — ±40 — — ±40 — V/µs

Aperture Delay Time — ±20 — — ±20 — — ±20 — ns

Aperture Uncertainty — 50 — — 50 — — 50 — ps rms

S/H Acquisition Time

(to ±0.003%FSR, 10V step) 1335 1390 1445 1335 1390 1445 1335 1390 1445 ns

Overvoltage Recovery Time ➄ — 1400 2000 — 1400 2000 — 1400 2000 ns

A/D Conversion Rate 500 — — 500 — — 500 — — MHz

FUNCTIONAL SPECIFICATIONS

(TA = +25°C, ±VCC = ±15V (or ±12V), +VDD = +5V, 500kHz sampling rate, and a minimum 1 minute warmup ➀ unless otherwise speciﬁ ed.)

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

01 Apr 2011 MDA_ADS-926.B02 Page 2 of 8

TECHNICAL NOTES

+25°C 0 to +70°C –55 to +125°C

ANALOG OUTPUT MIN. TYP. MAX. MIN. TYP. MAX. MIN. TYP. MAX. UNITS

Internal Reference

Voltage +9.95 +10.0 +10.05 +9.95 +10.0 +10.05 +9.95 +10.0 +10.05 Volts

Drift — ±5 — — ±5 — — ±5 — ppm/°C

External Current — — 1.5 — — 1.5 — — 1.5 mA

DIGITAL OUTPUTS

Logic Levels

Logic "1" +2.4 — — +2.4 — — +2.4 — — Volts

Logic "0" — — +0.4 — — +0.4 — — +0.4 Volts

Logic Loading "1" — — –4 — — –4 — — –4 mA

Logic Loading "0" — — +4 — — +4 — — +4 mA

Delay, Falling Edge of EOC to

Output Data Valid — — 35 — — 35 — — 35 ns

Output Coding Offset Binary

POWER REQUIREMENTS , ±15V

Power Supply Ranges

+15V Supply +14.5 +15.0 +15.5 +14.5 +15.0 +15.5 +14.5 +15.0 +15.5 Volts

–15V Supply –14.5 –15.0 –15.5 –14.5 –15.0 –15.5 –14.5 –15.0 –15.5 Volts

+5V Supply +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 Volts

Power Supply Currents

+15V Supply — +41 +63 — +41 +63 — +41 +63 mA

–15V Supply — –23 –40 — –23 –40 — –23 –40 mA

+5V Supply — +71 +85 — +71 +85 — +71 +85 mA

Power Dissipation — 1.4 1.75 — 1.4 1.75 — 1.4 1.75 Watts

Power Supply Rejection — — ±0.02 — — ±0.02 — — ±0.02 %FSR/%V

POWER REQUIREMENTS, ±12V

Power Supply Ranges

+12V Supply +14.5 +15.0 +15.5 +14.5 +15.0 +15.5 +14.5 +15.0 +15.5 Volts

–12V Supply –14.5 –15.0 –15.5 –14.5 –15.0 –15.5 –14.5 –15.0 –15.5 Volts

+5V Supply +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 +4.75 +5.0 +5.25 Volts

Power Supply Currents

+12V Supply — +41 +60 — +41 +60 — +41 +60 mA

–12V Supply — –23 –40 — –23 –40 — –23 –40 mA

+5V Supply — +71 +85 — +71 +85 — +71 +85 mA

Power Dissipation — 1.3 1.6 — 1.3 1.6 — 1.3 1.6 Watts

Power Supply Rejection — — ±0.02 — — ±0.02 — — ±0.02 %FSR/%V

Footnotes:

➀ All power supplies must be on before applying a start convert pulse. All supplies and

the clock (START CONVERT) must be present during warmup periods. The device

must be continuously converting during this time.

➁ See Ordering Information for 0 to +10V input range. Contact DATEL for availability of

other input voltage ranges.

➂ A 500kHz clock with a 200ns wide start convert pulse is used for all production

testing. For applications requiring less than a 500kHz sampling rate, wider start

convert pulses can be used. See Timing Diagram for more details.

➄ This is the time required before the A/D output data is valid after the analog input is

back within the speciﬁ ed range.

(SNR + Distortion) – 1.76 + 20 log Full Scale Amplitude

Actual Input Amplitude

6.02

➃ Effective bits is equal to:

1. Obtaining fully speciﬁ ed performance from the ADS-926 requires care-

ful attention to pc-card layout and power supply decoupling. The device's

analog and digital ground systems are connected to each other internally.

For optimal performance, tie all ground pins (14, 19 and 23) directly to a

large analog ground plane beneath the package.

Bypass all power supplies and the REFERENCE OUTPUT (pin 21) to ground

with 4.7F tantalum capacitors in parallel with 0.1F ceramic capacitors.

Locate the bypass capacitors as close to the unit as possible. If the user-

installed offset and gain adjusting circuit shown in Figure 2 is used, also

locate it as close to the ADS-926 as possible.

2. The ADS-926 achieves its speciﬁ ed accuracies without the need for exter-

nal calibration. If required, the device's small initial offset and gain errors

can be reduced to zero using the input circuit of Figure 2. When using this

circuit, or any similar offset and gain-calibration hardware, make adjust-

ments following warmup. To avoid interaction, always adjust offset before

gain.

3. When operating the ADS-926 from ±12V supplies, do not drive external

circuitry with the REFERENCE OUTPUT. The reference's accuracy and drift

speciﬁ cations may not be met, and loading the circuit may cause accuracy

errors within the converter.

4. Applying a start convert pulse while a conversion is in progress (EOC =

logic "1") initiates a new and inaccurate conversion cycle. Data from the

interrupted and subsequent conversions will be invalid.

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

01 Apr 2011 MDA_ADS-926.B02 Page 3 of 8

To Pin 20

of ADS-926

15V

SIGNAL

INPUT

GAIN

ADJUST

1.98k:

50:

+15V

2k:

1.2M:

20k:

–15V

+15V

ZERO/

OFFSET

ADJUST

Figure 2. ADS-926 Calibration Circuit

ADS-926

BIT 1 (MSB)

BIT 2

BIT 3

BIT 4

BIT 5

BIT 6

BIT 7

BIT 8

BIT 9

BIT 10

BIT 11

BIT 12

BIT 13

BIT 14 (LSB)

EOC

ANALOG

INPUT

START

CONVERT

19, 23

0.1F4.7F

+5V

0.1F

4.7F

0.1F

4.7F

–

12V/–15V

+12V/+15V +

0.1F +

4.7F

21 +10V REF. OUT

–5V to +5V

DIGITAL

GROUND

ANALOG

GROUND

Figure 3. Typical ADS-926 Connection Diagram

CALIBRATION PROCEDURE (Refer to Figures 2 and 3)

Any offset and/or gain calibration procedures should not be implemented

until devices are fully warmed up. To avoid interaction, offset must be

adjusted before gain. The ranges of adjustment for the circuit of Figure 2

are guaranteed to compensate for the ADS-926's initial accuracy errors

and may not be able to compensate for additional system errors.

All ﬁ xed resistors in Figure 2 should be metal-ﬁ lm types, and multiturn

potentiometers should have TCR’s of 100ppm/°C or less to minimize drift

with temperature.

A/D converters are calibrated by positioning their digital outputs exactly

on the transition point between two adjacent digital output codes. This can

be accomplished by connecting LED's to the digital outputs and adjusting

until certain LED's "ﬂ icker" equally between on and off. Other approaches

employ digital comparators or microcontrollers to detect when the outputs

change from one code to the next.

For the ADS-926, offset adjusting is normally accomplished at the point

where the MSB is a 1 and all other output bits are 0's and the LSB just

changes from a 0 to a 1. This digital output transition ideally occurs when

the applied analog input is +½ LSB (+305V).

Gain adjusting is accomplished when all bits are 1's and the LSB just

changes from a 1 to a 0. This transition ideally occurs when the analog

input is at +full scale minus 1½ LSB's (+4.999085V).

Zero/Offset Adjust Procedure

1. Apply a train of pulses to the START CONVERT input (pin 16) so the con-

verter is continuously converting. If using LED's on the outputs, a 200kHz

conversion rate will reduce ﬂ icker.

2. Apply +305V to the ANALOG INPUT (pin 20).

3. Adjust the offset potentiometer until the output bits are a 1 and all 0's and

the LSB ﬂ ickers between 0 and 1.

Gain Adjust Procedure

1. 1. Apply +4.999085V to the ANALOG INPUT (pin 20).

2. Adjust the gain potentiometer until the output bits are all 1's and the LSB

ﬂ ickers between 1 and 0.

Table 2. Output Coding

OUTPUT CODING INPUT RANGE

±5V BIPOLAR SCALE

MSB LSB

11 1111 1111 1111 +4.99939 +FS –1 LSB

11 1000 0000 0000 +3.75000 +3/4 FS

11 0000 0000 0000 +2.50000 +1/2FS

10 0000 0000 0000 0.00000 0

01 0000 0000 0000 –2.50000 –1/2FS

00 1000 0000 0000 –3.75000 –3/4FS

00 0000 0000 0001 –4.99939 –FS +1 LSB

00 0000 0000 0000 –5.00000 –FS

Coding is offset binary; 1LSB = 610V.

Table 1. Zero and Gain Adjust

INPUT VOLTAGE

RANGE

ZERO ADJUST

+½ LSB

GAIN ADJUST

+FS –1½ LSB

±5V +305V +4.999085V

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

01 Apr 2011 MDA_ADS-926.B02 Page 4 of 8

Notes: 1. fs = 500kHz.

2. The ADS-926 is a pulse-triggered device. Its internal operations

are triggered by both the rising and falling edges of the start

convert pulse. When sampling at 500kHz, the start pulse must be

between 175 and 225nsec wide. For lower sampling rates, wider

start pulses may be used, however, a 50nsec minimum pulse

width low must be maintained.

START

CONVERT

OUTPUT

DATA

INTERNAL S/H

NN + 1

Data (N – 1) Valid

Acquisition Time

10ns typ.

Data N Valid (1885ns min.)

EOC

Conversion Time

Invalid

Data

115ns max.

10ns typ.

1390ns ±55ns

35ns max.

Hold

200ns

±25ns

610ns typ.

480ns ±20ns

70ns ±10ns

Figure 4. ADS-926 Timing Diagram

devices do not overheat. The ground and power planes beneath the package,

as well as all pcb signal runs to and from the device, should be as heavy as

possible to help conduct heat away from the package.

Electrically-insulating, thermally-conductive "pads" may be installed

underneath the package. Devices should be soldered to boards rather than

"socketed," and of course, minimal air ﬂ ow over the surface can greatly help

reduce the package temperature.

THERMAL REQUIREMENTS

All DATEL sampling A/D converters are fully characterized and speci-

ﬁ ed over operating temperature (case) ranges of 0 to +70°C and –55

to +125°C. All room-temperature (TA = +25°C) production testing is

performed without the use of heat sinks or forced-air cooling. Thermal

impedance ﬁ gures for each device are listed in their respective speciﬁ ca-

tion tables.

These devices do not normally require heat sinks; however, standard

precautionary design and layout procedures should be used to ensure

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

01 Apr 2011 MDA_ADS-926.B02 Page 5 of 8

Figure 5. ADS-926 Evaluation Board Schematic

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

01 Apr 2011 MDA_ADS-926.B02 Page 6 of 8

Figure 6. ADS-926 FFT Analysis

–10

–20

–30

–40

–50

–60

–70

–80

–90

–100

–110

–120

–130

–140

–150

Frequency (kHz)

(fs = 500kHz, fin = 240kHz, Vin = –0.5dB, 16,384-point FFT)

Amplitude Relative to Full Scale (dB)

0 25 50 75 100 125 150 175 200 225 250

Figure 7. ADS-926 Histogram and Differential Nonlinearity

Number of Occurrences

Digital Output Code

016,384

+0.59

–0.57

16,384

DNL (LSB's)

Digital Output Code

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

®®

DATEL • 11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA • Tel: (508) 339-3000 • www.datel.com • e-mail: help@datel.com

01 Apr 2011 MDA_ADS-926.B02 Page 7 of 8

MECHANICAL DIMENSIONS - INCHES (mm)

ORDERING INFORMATION

MODEL NUMBER OPERATING

TEMP. RANGE ANALOG INPUT ACCESSORIES

ADS-926MC 0 to +70°C Bipolar (±5V) ADS-B926/927 Evaluation Board (without ADS-926)

ADS-926MM –55 to +125°C Bipolar (±5V) HS-24 Heat Sinks for all ADS-916/926 DDIP models.

ADS-926/883 –55 to +125°C Bipolar (±5V)

Receptacles for PC board mounting can be ordered through AMP Inc.

Part #3-331272-8 (Component Lead Socket), 24 required.

For MIL-STD-883 product speciﬁ cations, contact DATEL.

* For information, see ADS-916 data sheet.

ADS-926GC 0 to +70°C Bipolar (±5V)

ADS-926GM –55 to +125°C Bipolar (±5V)

ADS-916MC 0 to +70°C Unipolar (0 to +10V)*

ADS-916MM –55 to +125°C Unipolar (0 to +10V)*

ADS-916GC 0 to +70°C Unipolar (0 to +10V)*

ADS-916GM –55 to +125°C Unipolar (0 to +10V)*

0.200 MAX.

(5.080)

0.235 MAX.

(5.969)

0.600 ±0.010

(15.240)

0.80 MAX.

(20.32)

0.100 TYP.

(2.540)

0.100

(2.540)

0.018 ±0.002

(0.457)

0.100

(2.540)

0.040

(1.016)

1.31 MAX.

(33.27)

112

1.100

(27.940)

0.190 MAX.

(4.826)

0.010

(0.254)

+0.002

–0.001

SEATING

PLANE

0.025

(0.635)

Dimension Tolerances (unless otherwise indicated):

2 place decimal (.XX) ±0.010 (±0.254)

3 place decimal (.XXX) ±0.005 (±0.127)

Lead Material: Kovar alloy

Lead Finish: 50 microinches (minimum) gold plating

over 100 microinches (nominal) nickel plating

PIN 1 INDEX

24-Pin DDIP

Versions

ADS-926MC

ADS-926MM

ADS-926/883

ADS-916MC

ADS-916MM

24-Pin

Surface Mount

Versions

ADS-926GC

ADS-926GM

ADS-916GC

ADS-916GM

0.80 MAX.

(20.32)

0.015

(0.381)

MAX. radius

for any pin

1.31 MAX.

(33.02)

0.100 TYP.

(2.540)

0.100

(2.540)

0.190 MAX.

(4.826)

0.040

(1.016)

0.020 TYP.

(0.508)

0.020

(0.508)

24 13

121

PIN 1

INDEX

0.130 TYP.

(3.302)

Dimension Tolerances (unless otherwise indicated):

2 place decimal (.XX) ±0.010 (±0.254)

3 place decimal (.XXX) ±0.005 (±0.127)

Lead Material: Kovar alloy

Lead Finish: 50 microinches (minimum) gold plating

over 100 microinches (nominal) nickel plating

0.060 TYP.

(1.524)

0.010 TYP.

(0.254)

ADS-926

14-Bit, 500kHz, Low-Power Sampling A/D Converters

. makes no representation that the use of its products in the circuits described herein, or the use of other

technical information contained herein, will not infringe upon existing or future patent rights. The descriptions contained herein do not

imply the granting of licenses to make, use, or sell equipment constructed in accordance therewith. Speciﬁ cations are subject to change

without notice.

www.datel.com • e-mail: help@datel.com

®®

DATEL

11 Cabot Boulevard, Mansﬁ eld, MA 02048-1151 USA

ITAR and ISO 9001/14001 REGISTERED

01 Apr 2011 MDA_ADS-926.B02 Page 8 of 8