AS1976 datasheet(14/17 Pages) AMSCO

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AS1976/AS1977

Data Sheet - A p p l i c a t i o n I n f o r m a t i o n

Logic-Level Translation

The AS1977 can be used as a 5V-to-3V logic translator. Figure 30 shows an application that converts 5V- to 3V-logic

levels, and provides the full 5V logic-swing without creating overvoltage on the 3V logic inputs.

Note:

When the comparator is powered by a 5V supply, RPULUP for the open-drain output should be connected to the

+3V supply voltage.

For 3V-to-5V logic-level translations, connect the +3V supply voltage to VCC and the +5V supply voltage to RPULUP.

Figure 30. AS1977 Logic-Level Translation Circuit

Layout Considerations

The AS1976/AS1977 requires proper layout and design techniques for optimum performance.

Power-supply bypass capacitors are not typically required, although 100nF bypass capacitors should be placed

close to the AS1976/AS1977 supply pins when supply impedance is high, leads are long, or for excessive noise on

the supply lines.

Minimize signal trace lengths to reduce stray capacitance.

A ground plane should be used.

Surface-mount components should be used whenever practical.

AS1977

RPullup

+5/+3V

Logic Out

+3/+5V

+5/+3V

Logic In

100k

+3/+5V

Logic-Level Translator

VCC

IN+

OUT

VEE

REF

AS1976 датащи(PDF) 14 Page - ams AG