ASM8500
Alliance Semiconductor
2575 Augustine Drive . Santa Clara, CA 95054 . Tel: 408.855.4900 . Fax: 408.855.4999 . www.alsc.com
Notice: The information in this document is subject to change without notice
rev 1.0
Low Power 5V / 3.3V µP Reset Active LOW, Open - Drain Output
November 2003
General Description
The ASM8500 is a voltage supervisory device with a low-power,
5V/3.3V µP Reset, active LOW, open-drain output. Maximum
supply current over temperature is a low 6µA.
The ASM8500 generates an active LOW reset signal whenever
the monitored supply is out of tolerance. A precision reference
and comparator circuit monitor power supply (V
CC
) level. Reset
threshold tolerance level is ±1.5%. When an out-of-tolerance
condition is detected, an internal power-fail signal is generated
which forces an active LOW reset signal. After V
CC
returns to
an in-tolerance condition, the reset signal remains active for
1.5ms to allow the power supply and system microprocessor to
stabilize.
The ASM8500 is designed with a open-drain output stage and
operates over the extended industrial temperature range.
Devices are available in compact surface mount SOT-89
packages.
Other low power products in this family include the ASM1810/
11/12/15/16/17, ASM1233D and ASM1233M.
Key Features
• Low Supply Current
• 6 µA maximum (5.5 V)
• Automatically restarts a microprocessor after power failure
• 1.5ms reset delay after V
CC
returns to an in-tolerance con-
dition
• Active LOW power-up reset
• Precision temperature-compensated voltage reference and
comparator
• Eliminates external components
• Compact surface mount SOT-89 package
• Operating temperature -40°C to +85°C
Applications
• Set-top boxes
• Cellular phones
•PDAs
• Energy management systems
• Embedded control systems
• Printers
• Single board computers
Typical Operating Circuit
Block Diagram
Microprocessor
V
CC
RESET
RESET
GND
ASM8500
V
CC
Supply
Reference
Delay
1.5ms
Typical
Tolerance
Bias
+
-
ASM8500
GND
RESET
5ΚΩ