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, 1.3 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 (1.3 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.
® ®
INNOV A TION and EX CELLENCE
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
RE
GI
ST
ER
RE
GI
ST
ER 3-S
TA
TE
O
UT
PU
T R
EG
IST
ER
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
DI
GI
TA
L C
OR
RE
CT
IO
N
LO
GI
C
FLASH
ADC
1
FLASH
ADC
2
Σ
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)