®

®

A SUBSIDIARY OF C&D TECHNOLOGIES

FEATURES

• 18-bit resolution

• 1MHz minimum sampling rate

• No missing codes over extended temperature range

• Very low power, 1.45 Watts

• Small, 32-pin, side-brazed, ceramic TDIP

• Edge-triggered

• Excellent performance, –95dB peak harmonics

• Ideal for both time and frequency-domain applications

• Low cost

ing temperature ranges. A proprietary, auto-calibrating, error-

correcting circuit enables the device to achieve specified per-

formance over the full military temperature range.

ADS-953

18-Bit, 1MHz, Low-Distortion

Sampling A/D Converters

GENERAL DESCRIPTION

The ADS-953 is an 18-bit, 1MHz sampling A/D converter. This

device accurately samples full-scale input signals up to Nyquist

frequencies with no missing codes. This feature, combined with

excellent signal-to-noise ratio (SNR) and –95dB peak harmonic

distortion (THD), makes the ADS-953 the ideal choice for both

time-domain (medical imaging, scanners, process control) and

frequency-domain (radar, telecommunications, spectrum analy-

sis) applications.

Packaged in a 32-pin, side-brazed, metal-sealed, ceramic TDIP,

the functionally complete ADS-953 contains a fast-settling sam-

ple-hold amplifier, a subranging (two-pass) A/D converter, an

internal reference, timing/control logic, and error-correction cir-

cuitry. Digital input and output levels are TTL, and the ADS-953

only requires the rising edge of the start convert pulse to

operate.

Requiring ±15V and ±5V supplies, the ADS-953 typically dis-

sipates 1.45 Watts. The device is offered with a bipolar (±5V)

analog input range. Models are available for use in either

commercial (0 to +70°C) or extended (–40 to +110°C) operat-

INPUT/OUTPUT CONNECTIONS

Figure 1. ADS-953 Functional Block Diagram

1

BIT 2

32

BIT 3

2

BIT 1 (MSB)

31

BIT 4

3

ANALOG GROUND

30

BIT 5

4

ANALOG INPUT

29

BIT 6

5

+5V REFERENCE OUT

28

BIT 7

6

GAIN ADJUST

27

BIT 8

7

COMPENSATION

26

BIT 9

8

–15V SUPPLY

25

BIT 10

9

+15V SUPPLY

24

BIT 11

10

+5V ANALOG SUPPLY

23

BIT 12

11

–5V ANALOG SUPPLY

22

BIT 13

12

ANALOG GROUND

21

BIT 14

13

DIGITAL GROUND

20

BIT 15

14

+5V DIGITAL SUPPLY

19

BIT 16

15

EOC

18

BIT 17

16

START CONVERT

17

BIT 18 (LSB)

PIN

FUNCTION

PIN

FUNCTION

DATEL, Inc., Mansfield, MA 02048 (USA)

• Tel: (508) 339-3000, (800) 233-2765 Fax: (508) 339-6356 • Email: sales@datel.com • Internet: www.datel.com

REF

DAC

2

BIT 1 (MSB)

1

BIT 2

32 BIT 3

31 BIT 4

30 BIT 5

29 BIT 6

28 BIT 7

27 BIT 8

26 BIT 9

25 BIT 10

24 BIT 11

23 BIT 12

22 BIT 13

21 BIT 14

20 BIT 15

19 BIT 16

18 BIT 17

17 BIT 18 (LSB)

TIMING AND

CONTROL LOGIC

ANALOG INPUT 4

START CONVERT 16

EOC 15

–

+

S/H

BUFFER

FLASH

ADC

1

FLASH

ADC

2

Σ

AMP

GAIN

CIRCUIT

COMPENSATION 7

+5V REFERENCE OUT 5

10

+5V ANALOG

SUPPLY

11

–5V ANALOG

SUPPLY

3, 12

ANALOG

GROUND

14

+5V DIGITAL

SUPPLY

9

+15V

SUPPLY

8

–15V

SUPPLY

13

DIGITAL

GROUND

GAIN ADJUST 6