ASM161, ASM162
mP Supervisory Circuit
Description
The ASM161 and ASM162 are cost effective, low power
supervisory circuits that monitor power supplies in microprocessor,
microcontroller and digital systems. If the power supply drops below
the reset threshold level, a reset is asserted and remains asserted for at
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least 800 ms after V
has risen above the reset threshold. An
CC
improved manual reset architecture gives the system designer
additional flexibility.
The debounced manual reset input is negative edge triggered. The
reset pulse period generated by a MR transition is a minimum of
800 ms and a maximum of 2 sec duration. In addition, The MR input
signal is blocked for an additional 49 mS minimum after the reset pulse
ends. During the MR disable period, the microcontroller is guaranteed
a time period free of additional manual reset signals. During this
period DRAM contents can be refreshed or other critical system tasks
undertaken. Low power consumption makes the ASM161/162 ideal
for use in portable and battery operated equipments. With 3 V
supplies, power consumption is 8 mW typically and 30 mW maximum.
The ASM161 has an open−drain, active−LOW RESET output and
requires an external pull−up resistor. The ASM162 has an active
HIGH RESET output.
The ASM161/162 are offered in compact 4−pin SOT−143 packages.
No external components are required to trim threshold voltage for
monitoring different supply voltages. With six different factory set,
reset, threshold ranges from 2.63 V to 4.63 V, the ASM161/162 are
suitable for monitoring 5 V, 3.6 V and 3.0 V supplies. The
ASM161/162 are available in temperature ranges 0°C to 70°C and
−40°C to +85°C.
SOT−143
4 LEAD
CASE 527AF
PIN CONFIGURATIONS
1
1
V
CC
V
CC
GND
GND
RESET
MR RESET
MR
ASM161
(Top View)
ASM162
(Top View)
RESET is open drain
RESET THRESHOLD
Part Suffix
Voltage (V)
4.63
L
M
J
Features
4.38
4.00
• Edge Triggered Manual Reset Input
• Single Pulse Output
• 49 mS Minimum MR Disable Period After Reset
• CMOS/TTL Logic or Switch Interface
• Debounced Input
T
S
R
3.08
2.93
2.63
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 6 of this data sheet.
• Low Supply Current Extends Battery Life
6 mA / 15 mA typ/max at 5.5 V
4.5 mA / 10 mA typ/max at 3.6 V
• Long Reset Period
Applications
• 0.8 Sec Minimum, 2 Sec Maximum
• PDAs
• Appliances
• Two Reset Polarity Options
ASM161: Active LOW, Open−drain
ASM162: Active HIGH
• Computers and Embedded Controllers
• Wireless Communication Systems
• Battery Operated and Intelligent Instruments
• Automotive Systems
• Pinout Matches the ASM811/812
• Small 4−Pin SOT−143 Package
• Two Temperature Ranges: 0°C to 70°C
and −40°C to +85°C
• Safety Systems
© Semiconductor Components Industries, LLC, 2011
1
Publication Order Number:
ASM161/D
August, 2011 − Rev. 3