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AS1976/AS1977

Data Sheet - D e t a i l e d D e s c r i p t i o n

8 Detailed Description

The AS1976/AS1977 are ultra low-current comparators and are guaranteed to operate with voltages as low as +1.8V.

The common-mode input voltage range extends 200mV beyond the rail voltages, and internal hysteresis ensures

clean output switching, even with slow input signals.

The AS1976 push/pull output stage sinks and sources-current. The AS1977 open-drain output stage can be pulled

put logic functions.

For all comparators, large internal output drivers allow rail-to-rail output swings with loads of up to 8mA. The output

stage design minimizes supply-current surges during switching, eliminating most power supply transients.

Input Stage

any differential input voltage within this range. The comparators have very low input bias current (±0.15nA, typ) if the

input voltage is within the common-mode voltage range.

Inputs are protected from over-voltage conditions by internal ESD protection diodes connected to the supply rails. As

the input voltage exceeds the supply rails, these ESD protection diodes are forward biased and begin to conduct.

Output Stage

The break-before-make output stage is capable of rail-to-rail operation with loads up to 8mA. Many comparators con-

sume orders of magnitude more current during switching than during steady-state operation.

1kHz. This characteristic reduces the need for power-supply filter capacitors to reduce transients created by compara-

tor switching currents.

Because of the unique design of its output stage, the AS1976/AS1977 can dramatically increase battery life, even in

high-speed applications.