CAT823 CATALYST [Catalyst Semiconductor], CAT823 Datasheet - Page 10

• Manufacturer Part Number: CAT823
• Description: System Supervisory Voltage Reset with Watchdog and Manual Reset
• Manufacturer: CATALYST [Catalyst Semiconductor]

CAT823, CAT824, CAT825
APPLICATION NOTES
µP’s with Bidirectional Reset Pins
The RESET
like the 68HC11 allowing for a system reset issued by
the processor. The maximum pullup current that can
be sourced by the CAT82_L/M is 1.5mA (and by the
CAT82_T/R/S/Z/Y is 800µA) allowing the processor to
pull the output low even when the CAT82x is pulling it
high.
Power Transients
Generally short duration negative-going transients of
less than 2µs on the power supply at V
will not cause a reset condition. However the lower
the voltage of the transient the shorter the required
time to cause a reset output.
usually be remedied by the proper location of bypass
capacitance on the circuit board.
Figure 8. RESET
Doc. No. MD-3027 Rev. A
¯¯¯¯¯¯ output can be pulled low by processors
¯¯¯¯¯¯ Valid to 0 Volts V
WDI
V
CC
CAT823
These issues can
CC
RST
minimum
MR
GND
RESET
10
OUTPUT VALID CONDITIONS
The RESET
maintain a valid output down to a V
sink current below 0.8V a resistor can be connected
from RESET
arrangement will maintain a valid value on the RESET
output during both power up and down but will draw
current when the RESET
resistor value of about 100kΩ  s hould be adequate in
most situations to maintain a low condition valid
output down to V
100kΩ
¯¯¯¯¯¯ output uses a push-pull output which can
¯¯¯¯¯¯ to Ground (see Figure 8.)
RESET
CC
¯¯¯¯¯¯ output is in the high state. A
µC
equal to 0V.
Characteristics subject to change without notice
CC
© Catalyst Semiconductor, Inc.
of 1.0 volts. To
¯¯¯¯¯¯
This