GENERAL DESCRIPTION

The ADS-939 is a 16-bit, 10MHz sampling A/D converter. This device

accurately samples full-scale input signals up to Nyquist frequencies with

no missing codes. The dynamic performance of the ADS-939 has been

optimized to achieve a signal-to-noise ratio (SNR) of 82dB and a total

harmonic distortion (THD) of –86dB.

Packaged in a 40-pin TDIP, the functionally complete ADS-939 contains a

fast-settling sample-hold amplifier, a subranging (two-pass) A/D converter,

an internal reference, timing/control logic, and error-correction circuitry.

Digital input and output levels are TTL. The ADS-939 only requires the

rising edge of the start convert pulse to operate.

Requiring ±5V supplies and either ±12v or ±15V supplies the ADS-939

dissipates 3.0 Watts. The device is offered with a bipolar (±2.75V) or a

unipolar (0 to –5.5V) analog input range. Models are available for use

in either commercial (0 to +70°C) or military (–55 to +125°C) operating

temperature ranges. A proprietary, auto-calibrating, error-correcting circuit

enables the device to achieve specified performance over the full military

temperature range. Typical applications include medical imaging, radar,

sonar, communications and instrumentation.

INPUT/OUTPUT CONNECTIONS

Figure 1. ADS-939 Functional Block Diagram

29 BIT 1 (MSB)

28 BIT 1 (MSB)

27 BIT 2

26 BIT 3

25 BIT 4

24 BIT 5

23 BIT 6

22 BIT 7

21 BIT 8

20 BIT 9

19 BIT 10

18 BIT 11

17 BIT 12

16 BIT 13

15 BIT 14

14 BIT 15

13 BIT 16 (LSB)

TIMING AND

CONTROL LOGIC

GAIN ADJUST 6

+3.2V REF. OUT 1

OFFSET ADJUST 5

EOC 32

+5V ANALOG SUPPLY

38

+5V DIGITAL SUPPLY

31

–5V SUPPLY

37

ANALOG GROUND

2, 4, 36

DIGITAL GROUND

7, 30

NO CONNECTION

39, 40

POWER AND GROUNDING

S/H

GAIN

ADJUST

CKT.

OFFSET

ADJUST

CKT.

PRECISION

+3.2V REFERENCE

ANALOG INPUT 3

START CONVERT 12

COMP. BITS 35

10 FSTAT1

11 FSTAT2

8 FIFO/DIR

9 FIFO/READ

34 OUTPUT ENABLE

33 OVERFLOW

POWER AND GROUNDING

+5V ANALOG SUPPLY

38

+5V DIGITAL SUPPLY

31

–5V SUPPLY

37

ANALOG GROUND

4, 36

DIGITAL GROUND

7, 30

–12/–15V ANALOG SUPPLY

39

+12/+15V ANALOG SUPPLY

40

UNIPOLAR 2

PIN

FUNCTION

PIN

FUNCTION

1

+3.2V REF. OUT

40

+12V/+15V

2

UNIPOLAR

39

–12V/–15V

3

ANALOG INPUT

38

+5V ANALOG SUPPLY

4

ANALOG GROUND

37

–5V SUPPLY

5

OFFSET ADJUST

36

ANALOG GROUND

6

GAIN ADJUST

35

COMP. BITS

7

DIGITAL GROUND

34

OUTPUT ENABLE

8

NC

33

OVERFLOW

9

NC

32

EOC

10

NC

31

+5V DIGITAL SUPPLY

11

NC

30

DIGITAL GROUND

12

START CONVERT

29

BIT 1 (MSB)

13

BIT 16 (LSB)

28

BIT 1 (MSB)

14

BIT 15

27

BIT 2

15

BIT 14

26

BIT 3

16

BIT 13

25

BIT 4

17

BIT 12

24

BIT 5

18

BIT 11

23

BIT 6

19

BIT 10

22

BIT 7

20

BIT 9

21

BIT 8

PRELIMINARY DATA

FEATURES

16-bit resolution

10MHz sampling rate

Functionally complete

No missing codes over full military temperature range

Edge-triggered

±5V, ±12V or ±15V supplies, 1.5 Watts

Small, 40-pin, ceramic TDIP

82dB SNR, –86dB THD

Ideal for both time and frequency-domain applications

MDA_ADS-939.A01 Page 1 of 7

ADS-939

16-Bit, 10MHz Sampling A/D Converters

For full details go to

www.murata-ps.com/rohs

www.murata-ps.com