REV.
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use, nor for any infringements of patents or other rights of third parties that
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under any patent or patent rights of Analog Devices.
a
Fast, Precision
Comparator
AD790
FEATURES
45 ns max Propagation Delay
Single 5 V or Dual ⴞ15 V Supply Operation
CMOS or TTL Compatible Output
250 V max Input Offset Voltage
500 V max Input Hysteresis Voltage
15 V max Differential Input Voltage
Onboard Latch
60 mW Power Dissipation
Available in 8-Pin Plastic and Hermetic Cerdip
Packages
Available in Tape and Reel in Accordance with
EIA-481A Standard
APPLICATIONS
Zero-Crossing Detectors
Overvoltage Detectors
Pulse-Width Modulators
Precision Rectifiers
Discrete A/D Converters
Delta-Sigma Modulator A/Ds
PRODUCT DESCRIPTION
The AD790 is a fast (45 ns), precise voltage comparator, with a
number of features that make it exceptionally versatile and easy
to use. The AD790 may operate from either a single 5 V supply
or a dual ±15 V supply. In the single-supply mode, the AD790’s
inputs may be referred to ground, a feature not found in other
comparators. In the dual-supply mode it has the unique ability
of handling a maximum differential voltage of 15 V across its in-
put terminals, easing their interfacing to large amplitude and
dynamic signals.
This device is fabricated using Analog Devices’ Complementary
Bipolar (CB) process—which gives the AD790’s combination
of fast response time and outstanding input voltage resolution
(1 mV max). To preserve its speed and accuracy, the AD790
incorporates a “low glitch” output stage that does not exhibit
the large current spikes normally found in TTL or CMOS output
stages. Its controlled switching reduces power supply disturbances
that can feed back to the input and cause undesired oscillations.
The AD790 also has a latching function which makes it suitable
for applications requiring synchronous operation.
The AD790 is available in five performance grades. The
AD790J and the AD790K are rated over the commercial tem-
perature range of 0°C to 70°C. The AD790A and AD790B are
rated over the industrial temperature range of –40°C to +85°C.
The AD790S is rated over the military temperature range of
–55°C to +125°C.
PRODUCT HIGHLIGHTS
1. The AD790’s combination of speed, precision, versatility
and low cost makes it suitable as a general purpose compara-
tor in analog signal processing and data acquisition systems.
2. Built-in hysteresis and a low-glitch output stage minimize the
chance of unwanted oscillations, making the AD790 easier to
use than standard open-loop comparators.
3. The hysteresis combined with a wide input voltage range
enables the AD790 to respond to both slow, low level (e.g.,
10 mV) signals and fast, large amplitude (e.g., 10 V) signals.
4. A wide variety of supply voltages is acceptable for operation
of the AD790, ranging from single 5 V to dual +5 V/–12 V,
± 5 V, or +5 V/± 15 V supplies.
5. The AD790’s power dissipation is the lowest of any compara-
tor in its speed range.
6. The AD790’s output swing is symmetric between V
LOGIC
and ground, thus providing a predictable output under a
wide range of input and output conditions.
CONNECTION DIAGRAMS
8-Pin Plastic Mini-DIP (N)
and Cerdip (Q) Packages
OUTPUT
LATCH
GROUND
V
LOGIC
1
2
3
45
6
7
8
AD790
–
+
+V
S
+IN
–IN
–V
S
8-Pin SOIC (R) Package
LATCH
GROUND
V
LOGIC
+V
S
1
2
3
4
5
6
7
8
OUTPUT
AD790
+
–
+IN
–IN
–V
S
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Tel: 781/329-4700www.analog.com
Fax: © Analog Devices, Inc.,
