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Ultrafast Comparators
AD96685/AD96687
FEATURES
AD96685 FUNCTIONAL BLOCK DIAGRAM
Fast: 2.5 ns Propagation Delay
Low Power: 118 mW per Comparator
Packages: DIP, SOIC, PLCC
Power Supplies: +5 V, –5.2 V
Logic Compatibility: ECL
50 ps Delay Dispersion
NONINVERTING
Q OUTPUT
INPUT
INVERTING
Q OUTPUT
INPUT
R
R
L
L
LATCH
ENABLE
V
T
APPLICATIONS
High Speed Triggers
High Speed Line Receivers
Threshold Detectors
Window Comparators
Peak Detectors
AD96687 FUNCTIONAL BLOCK DIAGRAM
NONINVERTING
NONINVERTING
INPUT
INPUT
Q OUTPUT Q OUTPUT
Q OUTPUT Q OUTPUT
INVERTING
INPUT
INVERTING
INPUT
R
R
R
R
L
L
L
L
LE LE
LE LE
V
T
LATCH
ENABLE
LATCH
ENABLE
THE OUTPUTS ARE OPEN EMITTERS, REQUIRING EXTERNAL
PULL-DOWN RESISTORS.THESE RESISTORS MAY BE INTHE
RANGE OF 50⍀-200⍀ CONNECTEDTO –2.0V, OR 200⍀-2000⍀
GENERAL DESCRIPTION
The AD96685 and AD96687 are ultrafast voltage comparators.
The AD96685 is a single comparator with 2.5 ns propagation
delay; the AD96687 is an equally fast dual comparator. Both
devices feature 50 ps propagation delay dispersion which is a
particularly important characteristic of high-speed comparators.
It is a measure of the difference in propagation delay under
differing overdrive conditions.
A fast, high precision differential input stage permits consistent
propagation delay with a wide variety of signals in the common-
mode range from –2.5 V to +5 V. Outputs are complementary
digital signals fully compatible with ECL 10 K and 10 KH logic
families. The outputs provide sufficient drive current to directly
drive transmission lines terminated in 50 Ω to –2 V. A level
sensitive latch input which permits tracking, track-hold, or
sample-hold modes of operation is included.
The AD96685 is available in industrial –25°C to +85°C range
in 16-pin SOIC.
The AD96687 is available in industrial range –25°C to +85°C,
in 16-pin DIP, SOIC, and 20-lead PLCC.
REV. D
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© Analog Devices, Inc., 2001