14-Bit, 10MHz
Sampling A/D Converters
DATEL, Inc., 11 Cabot Boulevard, Mansfi eld, MA 02048-1151 (U.S.A.) • Tel: (508) 339-3000 Fax: (508) 339-6356 • For immediate assistance: (800) 233-2765
Figure 1. ADS-945 Functional Block Diagram
FEATURES
• 14-bit resolution
• 10MHz minimum throughput
• Functionally complete
• No missing codes
• Low power, 4.0W
• Excellent dynamic performance
• Internally clamped input
• Edge triggered
• TTL compatible
• 2" x 4" module
• Very low profi le
GENERAL DESCRIPTION
The low-cost ADS-945 is a high-performance, 14-bit, 10MHz
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-945
has been optimized to achieve a THD of –80dB and a
SNR of 75dB.
Packaged in a 2" x 4" module, the functionally complete
ADS-945 contains a fast-settling sample/hold amplifi er, a
subranging (two-pass) A/D converter, a precise voltage
reference, timing/control logic, three-state outputs, and
error-correction circuitry. Digital inputs and outputs are TTL
compatible (except for pins 29 and 30 which are ECL).
Requiring ±15V, +5V and –5.2V supplies, the ADS-945 typically
dissipates 4.0W. 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.
1 ANALOG GROUND 70-76 ANALOG GROUND
4 ANALOG INPUT 69 +5V ANALOG SUPPLY
5-6 ANALOG GROUND 64-68 ANALOG GROUND
7 +10V REFERENCE OUT 63 –5.2V ANALOG SUPPLY
8 ANALOG GROUND 62 ANALOG GROUND
9 GAIN ADJUST 61 NO CONNECT
10-11 DO NOT CONNECT 58-60 DIGITAL GROUND
12 –15V SUPPLY 57 –5.2V DIGITAL SUPPLY
13 ANALOG GROUND 56 DO NOT CONNECT
14 +15V SUPPLY 55 +5V DIGITAL SUPPLY
15-17 ANALOG GROUND 54 DIGITAL GROUND
18 OFFSET ADJUST 53 BIT 1 (MSB)
19-25 ANALOG GROUND 52 BIT 2
26 MISSING PIN 51 BIT 3
27 DIGITAL GROUND 50 BIT 4
28 DIGITAL GROUND 49 BIT 5
29 T/H STATUS 48 BIT 6
30 T/H STATUS 47 BIT 7
31 DIGITAL GROUND 46 BIT 8
32 START CONVERT 45 BIT 9
33 OVERFLOW 44 BIT 10
34 OUTPUT ENABLE (OE) 43 BIT 11
35 DIGITAL GROUND 42 BIT 12
36 NO CONNECT 41 BIT 13
37 DIGITAL GROUND 40 BIT 14 (LSB)
38 DIGITAL GROUND 39 DIGITAL GROUND
INPUT/OUTPUT CONNECTIONS
PIN FUNCTION PIN FUNCTION
®®
ADS-945
REF
DAC
3
-
ST
AT
E
O
U
T
P
U
T

R
E
G
I
ST
ER
53
52
51
50
49
48
47
46
45
44
43
42
41
40
TIMING AND
CONTROL LOGIC
ANALOG INPUT 4
START CONVERT 32
T/H STATUS 29
+1
BUFFER
DI
GI
T
A
L
CORRE
CT
I
O
N
L
OGI
C
FLASH
ADC
1
FLASH
ADC
2
Σ
AMP
GAIN
CIRCUIT
GAIN ADJUST 9
OFFSET
CIRCUIT
OFFSET ADJUST 18
14
+15V
SUPPLY
12
–15V
SUPPLY
55
+5V DIGITAL
SUPPLY
34 OUTPUT ENABLE
T/H
+10 REF. OUT 7
T/H STATUS 30
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)
33 OVERFLOW
1,2,3,5,6,8,13,15,17,
19-25,62,64-68,70-76
ANALOG GROUND
27,28,31,35,37-39,54,58-60
DIGITAL
GROUND
36, 61
NO
CONNECT
57
–5.2V DIGITAL
SUPPLY
26 MISSING PIN
10,11,56 DO NOT CONNECT
CASE
DGND
AGND