MDC_ADS-949.B01 Page 1 of 8

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ADS 949

14 Bit, 12.8MHz

Sampling A/D Converters

Figure 1. ADS-949 Functional Block Diagram

FEATURES

• 14-bit resolution

• 12.8MHz minimum sampling rate

• No missing codes over full military temperature range

• Ideal for both time and frequency-domain applications

• Excellent THD (–81dB) and SNR (78dB)

• Edge-triggered

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

• Low-power, 2 Watts

• Low cost

GENERAL DESCRIPTION

The low-cost ADS-949 is a 14-bit, 12.8MHz sampling A/D

converter. This device accurately samples full-scale input

signals up to Nyquist frequencies with no missing codes.

Excellent differential nonlinearity error (DNL), signal-to-noise

ratio (SNR), and total harmonic distortion (THD) make the

ADS-949 the ideal choice for both time-domain (CCD/FPA

imaging, scanners, process control) and frequency-domain

(radar, telecommunications, spectrum analysis) applications.

The functionally complete ADS-949 contains a fast-settling

sample/hold amplifier, a subranging A/D converter, an internal

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

Digital input and output levels are TTL. The ADS-949 only

requires the rising edge of a start convert pulse to operate.

Requiring only +15V, +5V and –5V supplies, the ADS-949

typically dissipates just 2 Watts. The device is offered with a

Bipolar input range of ±2.5V and Unipolar range of 0 to 5 volts.

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 allows

the device to achieve specified performance over the full

military temperature range.

INPUT/OUTPUT CONNECTIONS

PIN

FUNCTION

PIN

FUNCTION

1

ViN A

32

RANgE

2

ViN B

31

gAiN ADjUST

3

–5V

30

+5V ANALog

4

oFFSET ADj.

29

ANALog gND

5

RANgE REF.

28

+15V

6

2.5V REF.

27

+5V DigiTAL

7

START CoNVERT

26

DigiTAL gND

8

EoC

25

oVERFLoW

9

ENABLE

24

MSB

10

BiT 14 (LSB)

23

BiT 1 (MSB)

11

BiT 13

22

BiT 2

12

BiT 12

21

BiT 3

13

BiT 11

20

BiT 4

14

BiT 10

19

BiT 5

15

BiT 9

18

BiT 6

16

BiT 8

17

BiT 7

REF

DAC

10 BIT 14 (LSB)

11 BIT 13

12 BIT 12

13 BIT 11

14 BIT 10

15 BIT 9

16 BIT 8

17 BIT 7

18 BIT 6

19 BIT 5

20 BIT 4

21 BIT 3

22 BIT 2

23 BIT 1 (MSB)

24 MSB

TIMING AND

CONTROL LOGIC

OFFSET ADJUST 4

VIN A

1

START CONVERT 7

EOC 8

GAIN ADJUST

31

+5V ANALOG SUPPLY

30

+5V DIGITAL SUPPLY

27

V RANGE

32

–5.2V SUPPLY

3

+15V SUPPLY

28

ANALOG GROUND

29

DIGITAL GROUND

26

–

+

S/H

BUFFER

FLASH

ADC

1

FLASH

ADC

2

POWER AND GROUNDING

�

AMP

9

ENABLE

25 OVERFLOW

VIN B

2

2.5 V REF 6