PIN FUNCTION PIN FUNCTION
1 +3.2V REF. OUT 40 NO CONNECTION
2 UNIPOLAR 39 NO CONNECTION
3 ANALOG INPUT 38 +5V ANALOG SUPPLY
4 ANALOG GROUND 37 –5V SUPPLY
5 OFFSET ADJUST 36 ANALOG GROUND
6 GAIN ADJUST 35 COMP. BITS
7 DIGITAL GROUND 34 OUTPUT ENABLE
8 FIFO/DIR 33 OVERFLOW
9 FIFO READ 32 EOC
10 FSTAT1 31 +5V DIGITAL SUPPLY
11 FSTAT2 30 DIGITAL GROUND
12 START CONVERT 29 BIT 1 (MSB)
13 BIT 16 (LSB) 28 BIT 1 (MSB)
14 BIT 15 27 BIT 2
15 BIT 14 26 BIT 3
16 BIT 13 25 BIT 4
17 BIT 12 24 BIT 5
18 BIT 11 23 BIT 6
19 BIT 10 22 BIT 7
20 BIT 9 21 BIT 8
FEATURES
• 16-bit resolution
• 3MHz sampling rate
• Functionally complete
• No missing codes over full military temperature range
• Edge-triggered
• ±5V supplies, 1.85 Watts
• Small, 40-pin, ceramic TDIP
• 85dB SNR, –84dB THD
• Ideal for both time and frequency-domain applications
16-Bit, 3MHz
Sampling A/D Converters
® ®
INNOV A TION and EX CELLENCE
GENERAL DESCRIPTION
The low-cost ADS-933 is a 16-bit, 3MHz 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-933 has been optimized to
achieve a signal-to-noise ratio (SNR) of 85dB and a total
harmonic distortion (THD) of –84dB.
Packaged in a 40-pin TDIP, the functionally complete
ADS-933 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. The ADS-933 only requires the
rising edge of the start convert pulse to operate.
Requiring only ±5V supplies, the ADS-933 dissipates 1.85
Watts. The device is offered with a bipolar (±2.75V) analog
input range and a unipolar 0 to –5.5V input range. 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 enables the device to achieve
specified performance over the full military temperature range.
Typical applications include medical imaging, radar, sonar,
communications and instrumentation.
INPUT/OUTPUT CONNECTIONS
ADS-933
DATEL, Inc., Mansfield, MA 02048 (USA) • Tel: (508)339-3000, (800)233-2765 Fax: (508) 339-6356 • E-mail: sales@datel.com • Internet: www.datel.com
Figure 1. ADS-933 Functional Block Diagram
PRELIMINARY PRODUCT DATA
3-
ST
AT
E
OU
TP
UT
R
EG
IS
TE
R
29 BIT 1 (MSB)
28 BIT 1 (MSB)
27 BIT 2
26 BIT 3
25 BIT 4
24 BIT 5
23 BIT 6
22 BIT 7
21 BIT 8
20 BIT 9
19 BIT 10
18 BIT 11
17 BIT 12
16 BIT 13
15 BIT 14
14 BIT 15
13 BIT 16 (LSB)
TIMING AND
CONTROL LOGIC
GAIN ADJUST 6
+3.2V REF. OUT 1
OFFSET ADJUST 5
EOC 32
+5V ANALOG SUPPLY 38
+5V DIGITAL SUPPLY 31
–5V SUPPLY 37
ANALOG GROUND 4, 36
DIGITAL GROUND 7, 30
NO CONNECTION 39, 40
CU
ST
OM
G
AT
E
AR
RA
Y
POWER AND GROUNDING
2-
PA
SS
A
NA
LO
G-
TO
-D
IG
ITA
L C
ON
VE
RT
ER
S/H
GAIN
ADJUST
CKT.
OFFSET
ADJUST
CKT.
PRECISION
+3.2V REFERENCE
ANALOG INPUT 3
START CONVERT 12
COMP. BITS 35
10 FSTAT1
11 FSTAT2
8 FIFO/DIR
9 FIFO/READ
34 OUTPUT ENABLE
33 OVERFLOW
UNIPOLAR 2
OFFSET ADJUST 5