Figure 1. ADS-118/118A Functional Block Diagram

FEATURES

••••• 12-bit resolution

••••• 5MHz minimum sampling rate

••••• Functionally complete

••••• Small 24-pin DDIP

••••• Requires only ±5V supplies

••••• Low-power, 1.8 Watts

••••• Outstanding dynamic performance

••••• No missing codes over full military temperature range

••••• Edge-triggered, no pipeline delay

••••• Ideal for both time and frequency-domain applications

GENERAL DESCRIPTION

DATEL's ADS-118 and ADS-118A are 12-bit, 5MHz, sampling

A/D converters packaged in space-saving 24-pin DDIP’s. The

ADS-118 offers an input range of ±1V and has three-state

outputs. The ADS-118A has an input range of ±1.25V and

features direct adjustment of offset error.

These functionally complete low-power devices (1.8 Watts)

contain an internal fast-settling sample/hold amplifier, a 12-bit

subranging A/D converter, a precise voltage reference, timing/

control logic, and error-correction circuitry. All timing and

control logic operates from the rising edge of a single start

convert pulse. Digital input and output levels are TTL. Models

are available for use in either commercial (0 to +70°C) or

military (–55 to +125°C) operating temperature ranges.

Applications include radar, transient signal analysis, process

control, medical/graphic imaging, and FFT spectrum analysis.

®

®

INNOVATION and EXCELLENCE

ADS-118, ADS-118A

12-Bit, 5MHz, Low-Power

Sampling A/D Converters

DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.) • Tel: (508) 339-3000 Fax: (508) 339-6356 • For immediate assistance: (800) 233-2765

INPUT/OUTPUT CONNECTIONS

PIN

FUNCTION

PIN

FUNCTION

1

BIT 12 (LSB)

24

NO CONNECTION

2

BIT 11

23

ANALOG GROUND

3

BIT 10

22

NO CONNECTION

4

BIT 9

21

+5V ANALOG SUPPLY

5

BIT 8

20

–5V SUPPLY

6

BIT 7

19

ANALOG INPUT

7

BIT 6

18

ANALOG GROUND

8

BIT 5

17

ENABLE/OFFSET ADJ.

9

BIT 4

16

START CONVERT

10

BIT 3

15

EOC

11

BIT 2

14

DIGITAL GROUND

12

BIT 1 (MSB)

13

+5V DIGITAL SUPPLY

*

* ADS-118, Pin 17 is ENABLE

ADS-118A, Pin 17 is OFFSET ADJUST

REF

DAC

12 BIT 1 (MSB)

11 BIT 2

10 BIT 3

9

BIT 4

8

BIT 5

7

BIT 6

6

BIT 7

5

BIT 9

4

BIT 9

3

BIT 10

2

BIT 11

1

BIT 12 (LSB)

TIMING AND

CONTROL LOGIC

OFFSET ADJUST 17

ANALOG INPUT 19

START CONVERT 16

EOC 15

–

+

S/H

BUFFER

FLASH

ADC

1

FLASH

ADC

2

S

AMP

21

+5V ANALOG

SUPPLY

20

–5V SUPPLY

18, 23

ANALOG

GROUND

13

+5V DIGITAL

SUPPLY

14

DIGITAL

GROUND

22, 24

NO CONNECT

(ADS-118A only)

17 ENABLE

(ADS-118A only)