Analog Devices AD790 Datasheet
Fast, Precision
OUTPUT
LATCH
GROUND
V
LOGIC
1
2
3
45
6
7
8
AD790
–
+
+V
S
+IN
–IN
–V
S
LATCH
GROUND
V
LOGIC
+V
S
1
2
3
4
5
6
7
8
OUTPUT
AD790
+
–
+IN
–IN
–V
S
a
FEATURES
45 ns max Propagation Delay
Single +5 V or Dual 615 V Supply Operation
CMOS or TTL Compatible Output
250 mV max Input Offset Voltage
500 mV 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
MIL-STD-883B Processing Available
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
Comparator
AD790
CONNECTION DIAGRAMS
8-Pin Plastic Mini-DIP (N)
and Cerdip (Q) Packages
8-Pin SOIC (R) Package
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 input 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 temperature
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 and is available processed to MIL-STD-883B, Rev. C.
PRODUCT HIGHLIGHTS
1. The AD790’s combination of speed, precision, versatility
and low cost makes it suitable as a general purpose comparator 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 are 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 comparator 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.
REV. B
Information furnished by Analog Devices is believed to be accurate and
reliable. However, no responsibility is assumed by Analog Devices for its
use, nor for any infringements of patents or other rights of third parties
which may result from its use. No license is granted by implication or
otherwise under any patent or patent rights of Analog Devices.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 617/329-4700 Fax: 617/326-8703
AD790–SPECIFICATIONS
DUAL SUPPLY
(Operation @ +258C and +VS = +15 V, –VS = –15 V, V
= +5 V unless otherwise noted)
LOGIC
AD790J/A AD790K/B AD790S
Parameter Conditions Min Typ Max Min Typ Max Min Typ Max Units
RESPONSE CHARACTERISTIC 100 mV Step
Propagation Delay, t
PD
5 mV Overdrive 40 45 40 45 40 45 ns
T
MIN
to T
MAX
45/50 45/50 60 ns
OUTPUT CHARACTERISTICS
Output HIGH Voltage, V
OH
1.6 mA Source 4.65 4.65 4.65
6.4 mA Source 4.3 4.45 4.3 4.45 4.3 4.45 V
Output LOW Voltage, V
OL
to T
T
MIN
MAX
1.6 mA Sink 0.35 0.35 0.35 V
4.3/4.3 4.3 4.3 V
6.4 mA Sink 0.44 0.5 0.44 0.5 0.44 0.5 V
T
INPUT CHARACTERISTICS
Offset Voltage
Hysteresis
1
2
to T
MIN
MAX
to T
T
MIN
MIN
to T
MAX
MAX
0.3 0.4 0.6 0.3 0.4 0.5 0.3 0.4 0.65 mV
T
0.5/0.5 0.5 0.5 V
0.2 1.0 0.05 0.25 0.2 1.0 mV
1.5 0.5 1.5 mV
Bias Current Either Input 2.5 5 1.8 3.5 2.5 5 µA
to T
T
MIN
MAX
6.5 4.5 7 µA
Offset Current 0.04 0.25 0.02 0.15 0.04 0.25 µA
to T
T
MIN
MAX
0.3 0.2 0.4 µA
Power Supply
Rejection Ratio DC V
±20% 80 90 88 100 80 90 dB
S
to T
T
MIN
MAX
76 88 85 93 76 85 dB
Input Voltage Range
Differential Voltage V
≤±15 V 6V
S
Common Mode –V
S
S
+VS–2 V – V
S
6V
S
+VS–2 V –V
6V
S
+VS–2 V V
V
S
Common Mode
Rejection Ratio –10 V<V
CM
80 95 88 105 80 95 dB
<+10 V
to T
T
MIN
MAX
76 90 85 100 76 88 dB
Input Impedance 20i220i220i2MΩipF
LATCH CHARACTERISTICS
Latch Hold Time, t
Latch Setup Time, t
LOW Input Level, V
H
S
IL
HIGH Input Level, V
T
to T
MIN
MIN
to T
MAX
MA X
IH
T
25 35 25 35 25 35 ns
510 510 510 ns
0.8 0.8 0.8 V
1.6 1.6 1.6 V
Latch Input Current 2.3 5 2.3 3.5 2.3 5 µA
T
SUPPLY CHARACTERISTICS
Diff Supply Voltage
3
Logic Supply T
V
T
to T
MIN
LOGIC
to T
MIN
to T
MIN
MAX
= 5 V
MAX
MAX
4.5 33 4.5 33 4.7 33 V
4.0 7 4.0 7 4.2 7 V
7 58µA
Quiescent Current
+V
–V
V
LOGIC
S
S
+VS = 15 V 8 10 8 10 8 10 mA
–VS = –15 V 4 5 4 5 4 5 mA
V
= 5 V 2 3.3 2 3.3 2 3.3 mA
LOGIC
Power Dissipation 242 242 242 mW
TEMPERATURE RANGE
Rated Performance T
NOTES
1
Defined as the average of the input voltages at the low to high and high to low transition points. Refer to Figure 14.
2
Defined as half the magnitude between the input voltages at the low to high and high to low transition points. Refer to Figure 14.
3
+VS must be no lower than (V
All min and max specifications are guaranteed. Specifications shown in boldface are tested on all production units at final test.
Specifications subject to change without notice.
–0.5 V) in any supply operating conditions, except during power up.
LOGIC
MIN
to T
MAX
0 to +70/–40 to +85 0 to +70/–40 to +85 –55 to +125 °C
–2–
REV. B
AD790
SINGLE SUPPLY
(Operation @ +258C and +VS = V
= +5 V, –VS = 0 V unless otherwise noted)
LOGIC
1
AD790J/A AD790K/B AD790S
Parameter Conditions Min Typ Max Min Typ Max Min Typ Max Units
RESPONSE CHARACTERISTIC 100 mV Step
Propagation Delay, t
PD
5 mV Overdrive 45 50 45 50 45 50 ns
T
MIN
to T
MAX
50/60 50/60 65 ns
OUTPUT CHARACTERISTICS
Output HIGH Voltage, V
OH
1.6 mA Source 4.65 4.65 4.65
6.4 mA Source 4.3 4.45 4.3 4.45 4.3 4.45 V
Output LOW Voltage, V
OL
to T
T
MIN
MAX
1.6 mA Sink 0.35 0.35 0.35 V
4.3 4.3 4.3 V
6.4 mA Sink 0.44 0.5 0.44 0.5 0.44 0.5 V
T
INPUT CHARACTERISTICS
Offset Voltage
Hysteresis
2
3
to T
MIN
MAX
to T
T
MIN
MIN
to T
MAX
MAX
0.3 0.5 0.75 0.3 0.5 0.65 0.3 0.7 1.0 mV
T
0.5 0.5 0.5 V
0.45 1.5 0.35 0.6 0.45 1.5 mV
2.0 0.85 2.0 mV
Bias Current Either Input 2.7 5 2.0 3.5 2.7 5 µA
to T
T
MIN
MAX
7 58µA
Offset Current 0.04 0.25 0.02 0.15 0.04 0.25 µA
to T
T
MIN
MAX
0.3 0.2 0.4 µA
Power Supply
Rejection Ratio DC 4.5 V≤V
T
≤5.5 V 80 90 86 100 80 90 dB
S
MIN
to T
MAX
76/76 88 82 93 76 85 dB
Input Voltage Range
Differential Voltage 6V
Common Mode 0 +V
S
–2 V 0 +VS–2 V 0 +VS–2 V V
S
6V
S
6V
V
S
Input Impedance 20i220i220i2MΩipF
LATCH CHARACTERISTICS
Latch Hold Time, t
Latch Setup Time, t
LOW Input Level, V
H
S
IL
HIGH Input Level, V
T
to T
MIN
MIN
to T
MAX
MAX
IH
T
25 35 25 35 25 35 ns
510 510 510 ns
0.8 0.8 0.8 V
1.6 1.6 1.6 V
Latch Input Current 2.3 5 2.3 3.5 2.3 5 µA
T
SUPPLY CHARACTERISTICS
Supply Voltage
4
to T
MIN
MAX
T
MIN
to T
MAX
4.5 7 4.5 7 4.7 7 V
7 58µA
Quiescent Current 10 12 10 12 10 12 mA
Power Dissipation 60 60 60 mW
TEMPERATURE RANGE
Rated Performance T
NOTES
1
Pin 1 tied to Pin 8, and Pin 4 tied to Pin 6.
2
Defined as the average of the input voltages at the low to high and high to low transition points. Refer to Figure 14.
3
Defined as half the magnitude between the input voltages at the low to high and high to low transition points. Refer to Figure 14.
4
–VS must not be connected above ground.
All min and max specifications are guaranteed. Specifications shown in boldface are tested on all production units at final test.
Specifications subject to change without notice.
MIN
to T
MAX
0 to +70/–40 to +85 0 to +70/–40 to +85 –55 to +125 °C
REV. B
–3–
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