MAX823 Maxim, MAX823 Datasheet - Page 5

• Manufacturer Part Number: MAX823
• Description: 5-Pin Microprocessor Supervisory Circuits
• Manufacturer: Maxim

Figure 1. Functional Diagram
______________________________________________________________Pin Description
MAX823
—
1
2
3
4
5
(MAX823/MAX825
(MAX823/MAX824
MAX824
5-Pin Microprocessor Supervisory Circuits
PIN
ONLY)
ONLY)
—
1
2
3
4
5
V
WDI
MR
CC
_______________________________________________________________________________________
MAX825
—
1
2
4
3
5
V
CC
NAME
RESET
RESET
GND
WDI
V
MR
CC
WATCHDOG
TRANSITION
DETECTOR
Active-Low Reset Output. Pulses low for 200ms when triggered, and remains
low whenever V
remains low for 200ms after one of the following occurs: V
reset threshold, the watchdog triggers a reset, or MR goes low to high.
Ground. 0V reference for all signals.
Manual-Reset Input. A logic low on MR asserts reset. Reset remains asserted as
long as MR is held low and for 200ms after MR returns high. The active-low input
has an internal 52kΩ pull-up resistor. It can be driven from a CMOS-logic line or
shorted to ground with a switch. Leave open or connect to V
Active-High Reset Output. Inverse of RESET.
Watchdog Input. If WDI remains either high or low for longer than the watch-
dog timeout period, the internal watchdog timer runs out and a reset is trig-
gered. The internal watchdog timer clears whenever reset is asserted, or
whenever WDI sees a rising or falling edge. If WDI is left unconnected or is
connected to a three-stated buffer output, the watchdog feature is disabled.
Supply Voltage
1.25V
CC
GND
is below the reset threshold or when MR is a logic low. It
GENERATOR
WATCHDOG
RESET
TIMER
FUNCTION
MAX823
MAX824
MAX825
RESET
RESET
(MAX824/MAX825
ONLY)
CC
CC
rises above the
if unused.
5