
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
Ideal for both time and frequency-domain applications
Low cost
operating temperature ranges. A proprietary, auto-calibrating,
error-correcting circuit enables the device to achieve speci-
fied performance over the full military temperature range.
PRELIMINARY PRODUCT DATA
ADS -951
18-Bit, 1MHz, Low-Power
Sampling A/D Converters
GENERAL DESCRIPTION
The ADS-951 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 total
harmonic distortion (THD), makes the ADS-951 the ideal
choice for both time-domain (medical imaging, scanners,
process control) and frequency-domain (radar, telecommunica-
tions, spectrum analysis) applications.
Packaged in a 32-pin, side-brazed, metal-sealed, ceramic
TDIP, the functionally complete ADS-951 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, and
the ADS-951 only requires the rising edge of the start convert
pulse to operate.
Requiring ±15V and ±5V supplies, the ADS-951 typically
dissipates 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)
INPUT/OUTPUT CONNECTIONS
Figure 1. ADS-951 Functional Block Diagram
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
BIT 2
BIT 1 (MSB)
ANALOG GROUND
ANALOG INPUT
+5V REFERENCE OUT
GAIN ADJUST
COMPENSATION
–15V SUPPLY
+15V SUPPLY
+5V ANALOG SUPPLY
–5V ANALOG SUPPLY
ANALOG GROUND
DIGITAL GROUND
+5V DIGITAL SUPPLY
EOC
START CONVERT
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12
BIT 13
BIT 14
BIT 15
BIT 16
BIT 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
D
FLASH
ADC
1
FLASH
ADC
2
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