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AS1920/AS1922

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

9 Application Information

Supply Monitoring

The AS1920/AS1922 are low-power, high-accuracy triple-supply monitoring circuits with a single 200ms microproces-

sor reset output.

inputs.

Power Detect

pin RESETN low as soon as the primary input pin is

≥1V or the secondary input pin is ≥1V.

Powerup

≥1V. As long as any one of the

nal timer will be started and RESETN will be driven high after 200ms.

Powerdown

Override Functions

Ensuring RESETN Valid for Supply Voltages < 1V

When the supplies drops below 1V the RESETN output current sink capability is greatly reduced. Stray currents and

stray capacitance to signals other than GND can cause the RESETN output to float. This is not relevant for most appli-

cations since most microprocessors and other circuits do not operate with a supply voltage < 1V.

In applications where the RESETN output must be valid down to 0V, a pulldown resistor from pin RESETN to ground

Figure 12. Typical Application w/Resistor on RESETN Output to GND

excess supply current, therefore a value of 100k

Ω is recommended for the pulldown resistor.

100k

Ω

3V

1.8V

Adjustable

Supply

1

RESETN

3

2

GND

4

5

AS1920/

AS1922