CAT884 Datasheet, PDF (5/8 Pages) ON Semiconductor – Quad Voltage Supervisor

CAT884
Detailed Description
The CAT884 is a space−saving, low−power, quad voltage
microprocessor supervisory circuit designed monitor 4
voltage supplies.
Applications Information
Reset Output
CAT884 provides an active LOW system reset signal via
an open drain output which requires an external pull−up
resistor to an external power supply. This supply can be less
than or greater than V_DD, but should not exceed 5.5 V. When
the external pull−up voltage is greater than V_DD reverse
current flow from the external pull−up voltage to V_DD is
prevented by CAT884’s internal circuitry.
V_DD is also a monitored voltage in CAT884 with
thresholds set for 2.6 V rising and 2.4 V falling. When any
monitored supply drops below its threshold, the reset output
asserts LOW and remains LOW as long as V_DD is above
1.0 V.
CAT884
3.3 V
V1
V_DD
V2 RESET
V3
V4
5V
mP
RESET
Figure 7. Interfacing to Different Logic−Supply
Voltage
V_DD
0
V_MON
0
MR
0
RST
0
V_POR
1V
V_TH
t_RPD
t_FIL
<t_FIL
>T_PW
t_RD
t_MD
t_MR
Figure 8. Operational Timing Diagram
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