CAT809, CAT810
DETAILED DESCRIPTIONS
RESET TIMING
TheresetsignalisassertedLOWfortheCAT809andHIGHfortheCAT810whenthepowersupplyvoltage fallsbelow
the threshold trip voltage and remains asserted for at least 140ms after the power supply voltage has risen above the
threshold.
Threshold
Voltage
Power
Supply
Voltage
5V
0V
Reset Timeout Period
140ms
minimum
5V
0V
5V
0V
CAT809
CAT810
RESET
RESET
FIGURE 1. RESET TIMING DIAGRAM
V
CC
TRANSIENT RESPONSE
The CAT809/810 protect µPs against brownout failure. Short duration transients of 4µsec or less and 100 mV
amplitude typically do not cause a false RESET.
Figure 2 shows the maximum pulse duration of negative-going VCC transients that do not cause a reset condition. As
the amplitude of the transient goes further below the threshold (increasing VTH - VCC), the maximum pulse duration
decreases. In this test, the VCC starts from an initial voltage of 0.5V above the threshold and drops below it by the
amplitude of the overdrive voltage (VTH - VCC).
30
T
= 25°C
AMB
25
20
15
10
5
CAT809Z
CAT809M
10
0
1
100
1000
RESET OVERDRIVE V - V [mV]
TH CC
FIGURE 2. Maximum Transient Duration Without Causing a Reset Pulse vs. Reset Comparator Overdrive
Patent Pending
Doc. No. 3004, Rev. S
7
CATALYST [ CATALYST SEMICONDUCTOR ]
