CAT853, CAT863, CAT859, CAT869

© 2009 SCILLC. All rights reserved.

5

Doc. No. MD-3026, Rev. G

Characteristics subject to change without notice

DETAILED DESCRIPTION

RESET TIMING

The reset signal is asserted low for the CAT853,

CAT863, CAT859, and CAT869 when the power

supply voltage falls below the threshold trip voltage

and remains asserted for at least 140 ms after the

power supply voltage has risen above the threshold.

Figure 1. Reset Timing Diagram

The CAT853, CAT863, CAT859, and CAT869 protect

µPs

against

brownout

failure.

Short

duration

transients of 4 µs or less and 100 mV amplitude

typically do not cause a false RESET.

Figure 2 shows the maximum pulse duration of

reset condition. As the amplitude of the transient goes

maximum pulse duration decreases. In this test, the

threshold and drops below it by the amplitude of the

Figure 2. Maximum Transient Duration Without Causing a Reset Pulse vs. Reset Comparator Overdrive

5 V

0 V

5 V

0 V

Threshold

Voltage

140 ms

minimum

Reset Timeout Period

Power

Supply

Voltage

RESET

“C” THRESHOLD

“M” THRESHOLD