MAX6366PKA23-T Maxim Integrated, MAX6366PKA23-T Datasheet - Page 11

• Manufacturer Part Number: MAX6366PKA23-T
• Description: Supervisory Circuits
• Manufacturer: Maxim Integrated
• Series: MAX6365, MAX6366, MAX6367, MAX6368r

Specifications of MAX6366PKA23-T

• Number Of Voltages Monitored: 1
• Monitored Voltage: 2.5 V, 3 V, 3.3 V, 5 V
• Undervoltage Threshold: 2.25 V
• Overvoltage Threshold: 2.38 V
• Output Type: Active Low, Open Drain
• Manual Reset: Not Resettable
• Watchdog: Watchdog
• Battery Backup Switching: Backup
• Power-up Reset Delay (typ): 280 ms
• Supply Voltage - Max: 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Package / Case: SOT-23
• Chip Enable Signals: Yes
• Maximum Power Dissipation: 700 mW
• Minimum Operating Temperature: - 40 C
• Power Fail Detection: No
• Supply Current (typ): 15 uA
• Supply Voltage - Min: 0 V

One way to help the watchdog timer monitor the soft-
ware execution more closely is to set and reset the
watchdog at different points in the program rather than
pulsing the watchdog input periodically. Figure 4
shows a flow diagram in which the I/O driving the
watchdog is set low in the beginning of the program,
set high at the beginning of every subroutine or loop,
and set low again when the program returns to the
beginning. If the program should hang in any subrou-
tine, the problem would be quickly corrected.
When V
be removed without danger of triggering a reset pulse.
The device does not enter battery-backup mode when
V
These supervisors are relatively immune to short-dura-
tion, negative-going V
Figure 3. MAX6367 BATT ON Driving an External Pass
Transistor
CC
stays above the reset threshold voltage.
+2.4V TO +5.5V
CC
with Battery Backup and Chip-Enable Gating
Watchdog Software Considerations
is above V
SOT23, Low-Power µP Supervisory Circuits
V
BATT
GND
CC
MAX6367
Negative-Going V CC Transients
Replacing the Backup Battery
BATT ON
______________________________________________________________________________________
CE OUT
RESET
CE IN
OUT
TH
CC
, the backup power source can
transients. Resetting the µP
ADDRESS
DECODE
0.1µF
CE
CMOS RAM
RESET
A0–A15
µP
when V
desirable.
The Typical Operating Characteristics section has a
Maximum Transient Duration vs. Reset Threshold
Overdrive graph for which reset is not asserted. The
graph was produced using negative-going V
starting at V
the magnitude indicated (reset threshold overdrive).
The graph shows the maximum pulse width that a neg-
ative-going V
triggering a reset pulse. As the amplitude of the tran-
sient increases (i.e., goes further below the reset
threshold), the maximum allowable pulse width
decreases. Typically, a V
below the reset threshold and lasts for 30µs will not trig-
ger a reset pulse.
A 0.1µF bypass capacitor mounted close to the V
pin provides additional transient immunity.
Figure 4. Watchdog Flow Diagram
CC
experiences only small glitches is usually not
CC
CC
and ending below the reset threshold by
transient can typically have without
OR PROGRAM LOOP
SUBROUTINE
CC
SET WDI
RETURN
START
LOW
HIGH
END
WDI
SET
transient that goes 100mV
CC
pulses,
CC
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