CAT811 CATALYST [Catalyst Semiconductor], CAT811 Datasheet - Page 7

• Manufacturer Part Number: CAT811
• Description: 4-Pin Microprocessor Power Supply Supervisors
• Manufacturer: CATALYST [Catalyst Semiconductor]

Patent Pending
The reset signal is asserted LOW for the CAT811 and HIGH for the CAT812 when the power supply voltage falls below
the threshold trip voltage and remains asserted for at least 140ms after the power supply voltage has risen above the
threshold.
The CAT811/812 protect Ps against brownout failure. Short duration transients of 4 sec or less and 100 mV
amplitude typically do not cause a false RESET.
Figure 2 shows the maximum pulse duration of negative-going V
the amplitude of the transient goes further below the threshold (increasing V
decreases. In this test, the V
amplitude of the overdrive voltage (V
Voltage
RESET
RESET
Supply
Power
5V
0V
5V
0V
5V
0V
CC
starts from an initial voltage of 0.5V above the threshold and drops below it by the
TH
30
25
20
15
10
5
0
- V
1
RESET OVERDRIVE V TH - V CC [mV]
CC
).
CAT8xxM
10
7
T AMB = 25 C
100
CAT8xxZ
CC
transients that do not cause a reset condition. As
Threshold
Voltage
1000
TH
- V
minimum
CC
140ms
), the maximum pulse duration
Reset Timeout Period
CAT812
CAT811
Doc. No. 3005, Rev. P