®
®
ADS-944
14-Bit, 5MHz
Sampling A/D Converters
FEATURES
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14-bit resolution
5MHz minimum sampling rate
No missing codes over full military temperature range
Edge-triggered, no pipeline delay
Low power, 2.95 Watts
Small, 32-pin, ceramic TDIP package
SMT package available
Excellent dynamic performance
MIL-STD-883 screening or DESC SMD available
INPUT/OUTPUT CONNECTIONS
GENERAL DESCRIPTION
The low-cost ADS-944 is a high-performance, 14-bit, 5MHz
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-944 has been
optimized to achieve a THD of –77dB and a SNR of 76dB.
Packaged in a small, 32-pin TDIP, the functionally complete
ADS-944 contains a fast-settling sample-hold amplifier, a
subranging (two-pass) A/D converter, an internal reference,
timing and control logic, three-state outputs, and error-
correction circuitry. Digital input and output levels are TTL.
Requiring ±15V, +5V and –5.2V supplies, the ADS-944
typically dissipates 2.95 Watts. The unit is offered with a
bipolar input range of ±1.25V. Models are available for use in
either commercial (0 to +70°C) or military (–55 to +125°C)
operating temperature ranges. Typical applications include
radar signal analysis, medical/graphic imaging, and
FFT spectrum analysis.
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
FUNCTION
+5V ANALOG SUPPLY
–5.2V DIGITAL SUPPLY
ANALOG INPUT
ANALOG GROUND
OFFSET ADJUST
ANALOG GROUND
GAIN ADJUST
COMP. BITS
OUTPUT ENABLE
+5V DIGITAL SUPPLY
ANALOG GROUND
+15V SUPPLY
–15V SUPPLY
–5.2V ANALOG SUPPLY
DIGITAL GROUND
EOC
PIN
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
FUNCTION
START CONVERT
BIT 1 (MSB)
BIT 1 (MSB)
BIT 2
BIT 3
BIT 4
BIT 5
BIT 6
BIT 7
BIT 8
BIT 9
BIT 10
BIT 11
BIT 12
BIT 13
BIT 14 (LSB)
BUFFER
ANALOG INPUT 3
–
S/H
+
FLASH
ADC
1
31 BIT 1 (MSB)
30 BIT 1 (MSB)
29 BIT 2
DIGITAL CORRECTION LOGIC
3-STATE OUTPUT REGISTER
28 BIT 3
27 BIT 4
26 BIT 5
25 BIT 6
24 BIT 7
23 BIT 8
22 BIT 9
21 BIT 10
20 BIT 11
19 BIT 12
18 BIT 13
17 BIT 14 (LSB)
GAIN ADJUST 7
GAIN
CIRCUIT
REF
Σ
DAC
OFFSET ADJUST 5
OFFSET
CIRCUIT
AMP
FLASH
ADC
2
START CONVERT 32
EOC 16
TIMING AND
CONTROL LOGIC
9 OUTPUT ENABLE
1
+5V
ANALOG
SUPPLY
2
–5.2V
DIGITAL
SUPPLY
4, 6, 11
ANALOG
GROUND
10
+5V
DIGITAL
SUPPLY
12
+15V
SUPPLY
14
–5.2V
ANALOG
SUPPLY
15
DIGITAL
GROUND
8
COMP.
BITS
Figure 1. ADS-944 Functional Block Diagram
DATEL, Inc., 11 Cabot Boulevard, Mansfield, MA 02048-1151 (U.S.A.)
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Tel: (508) 339-3000 Fax: (508) 339-6356
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For immediate assistance: (800) 233-2765
MURATA-PS [ MURATA POWER SOLUTIONS INC. ]
