CAT1026, CAT1027
PIN DESCRIPTION
RESET/RESET: RESET OUTPUTS
(RESET CAT1026 Only)
VSENSE: AUXILIARY VOLTAGE MONITOR INPUT
The VSENSE input is a second voltage monitor which
is compared against CAT1026 and CAT1027 internal
reference voltage of 1.25V typically. Whenever the
input voltage is lower than 1.25V, the open drain
VLOW output will be driven low. An external resistor
divider is used to set the voltage level to be sensed.
Connect VSENSE to VCC if unused.
These are open drain pins and RESET can be used as a
manual reset trigger input. By forcing a reset condition on
thepinthedevicewillinitiateandmaintainaresetcondition.
The RESET pin must be connected through a pull-down
resistor, and the RESET pin must be connected through a
pull-up resistor.
VLOW: AUXILIARY VOLTAGE MONITOR OUTPUT
This open drain output goes low when VSENSE is less
than 1.25V and goes high when VSENSE exceeds the
SDA: SERIAL DATA ADDRESS
Thebidirectionalserialdata/addresspinisusedtotransfer
all data into and out of the device. The SDA pin is an open
drain output and can be wire-ORed with other open drain
or open collector outputs.
reference voltage.
WDI (CAT1027 Only): WATCHDOG TIMER INTERRUPT
Watchdog Timer Interrupt Input is used to reset the
watchdog timer. If a transition from high to low or low to
high does not occur every 1.6 seconds, the RESET
outputs will be driven active.
SCL: SERIAL CLOCK
Serial clock input.
PIN FUNCTIONS
OPERATING TEMPERATURE RANGE
Pin Name
RESET
VSS
Function
Active Low Reset Input/Output
Industrial
Extended
-40˚C to 85˚C
-40˚C to 125˚C
Ground
SDA
Serial Data/Address
SCL
Clock Input
RESET
VCC
Active High Reset Output (CAT1026 only)
Power Supply
VSENSE
VLOW
Auxiliary Voltage Monitor Input
Auxiliary Voltage Monitor Output
WatchdogTimerInterrupt(CAT1027only)
WDI
CAT10XX FAMILY OVERVIEW
Manual
Reset
Input Pin
Watchdog
Monitor
Pin
Write
Protection
Pin
Independent
Auxiliary
Voltage Sense
RESET: Active
High and LOW
Device
Watchdog
EEPROM
CAT1021
SDA
2k
CAT1022
CAT1023
CAT1024
CAT1025
CAT1026
CAT1027
SDA
WDI
2k
2k
2k
2k
2k
2k
WDI
For supervisory circuits with embedded 16k EEPROM, please refer to the CAT1161, CAT1162 and CAT1163
data sheets.
Doc No. 3010, Rev. K
3
CATALYST [ CATALYST SEMICONDUCTOR ]
