CAT853 Datasheet, PDF (5/10 Pages) Catalyst Semiconductor – 3-Pin Microprocessor Power Supply Supervisors

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.
CAT853, CAT863, CAT859, CAT869
Power _{5 V}
Supply
Voltage _{0 V}
5V
RESET
0V
Threshold
Voltage
Reset Timeout Period
140 ms
minimum
Figure 1. Reset Timing Diagram
V_CC TRANSIENT RESPONSE
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
negative-going V_CC transients that do not cause a
reset condition. As the amplitude of the transient goes
further below the threshold (increasing V_TH - V_CC), the
maximum pulse duration decreases. In this test, the
V_CC starts from an initial voltage of 0.5 V above the
threshold and drops below it by the amplitude of the
overdrive voltage (V_TH - V_CC).
T_AMB = 25ºC
“C” THRESHOLD
“M” THRESHOLD
RESET OVERDRIVE V_TH - V_CC [mV]
Figure 2. Maximum Transient Duration Without Causing a Reset Pulse vs. Reset Comparator Overdrive
© 2009 SCILLC. All rights reserved.
5
Characteristics subject to change without notice
Doc. No. MD-3026, Rev. G