Alliance Semiconductor ASM1810 Service Manual
查询ASM1810供应商
February 2005
rev 1.4
Low Power, 5V µP Reset
- Active LOW, Push-Pull Output
General Description
The ASM1810 is a voltage supervisor with low-power, 5V µP
active LOW Reset, Push-Pull output. Maximum supply current
over temperature is a low 20µA.
The ASM1810 generates an active LOW reset signal whenever
the monitored supply is out of tolerance. A precision reference
and comparator circuit monitor power supply (V
Tolerance level options are 5%, 10% and 15%. When an out-of-
tolerance condition is detected, an internal power-fail signal is
generated which forces an active LOW reset signal. After V
returns to an in-tolerance condition, the reset signal remains
active for 150ms to allow the power supply and system
microprocessor to stabilize.
) level.
CC
ASM1810
Key Features
• Low Supply Current
•20 µA maximum (5.5 V)
• Automatically restarts a microprocessor after power failure
• 150ms reset delay after V
dition
• Active LOW power-up reset
• Precision temperature-compensated voltage reference and
comparator
• Eliminates external components
• Low cost TO-92 and compact surface mount SOT-23 pack-
CC
age
• Push-Pull output for minimum current drain
• Operating temperature -40°C to +85°C
returns to an in-tolerance con-
CC
The ASM1810 is designed with a push-pull output stage and
operates over the extended industrial temperature range.
Devices are available in low cost TO-92 and compact surface
mount SOT-23 packages.
Other low power products in this family include the ASM1811/
12/15/16/17, ASM1233D and ASM1233M.
Typical Operating Circuit
V
CC
ASM1810
Microprocessor
RESET
GND
RESET
Applications
• Set-top boxes
• Cellular phones
•PDAs
• Energy management systems
• Embedded control systems
• Printers
• Single board computers
Block Diagram
V
V
2
CC
CC
ASM1810
Supply
Supply
Tolerance
Tolerance
Bias
Bias
Reference
Reference
+
+
-
-
ASM1810
Delay
Delay
150ms
150ms
Typical
Typical
1
RESET
RESET
3
GND
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
February 2005
rev 1.4
Pin Configuration
RESET
1
ASM1810
TO-92
SOT-23
ASM1810
V
CC
Pin Description
SOT-23 TO-92
Pin # Pin #
11RESET
22
3 3 GND Ground
ASM1810-R
2
GND
3
2
1
Pin Name Description
Active LOW reset output
V
CC
Power supply input
3
Low Power, 5V µP Reset
Notice: The information in this document is subject to change without notice
2 of 9
February 2005
rev 1.4
Application Information
ASM1810
Operation - Power Monitor
The ASM1810 detects out-of-tolerance power supply
conditions. It resets a processor during power-up, power-down
and issues a reset to the system processor when the monitored
power supply voltage is below the reset threshold. When an
out-of-tolerance V
asserted. On power-up, RESET is kept active (LOW) for
approximately 150ms after the power supply voltage has
reached the selected tolerance. This allows the power supply
and microprocessor to stabilize before RESET
voltage is detected, the RESET signal is
CC
is released.
ASM1810
Microprocessor
RESET
RESET
100kΩ
t
R
V
(MIN)
V
CCTP
~
~
V
CC
~
RESET
Figure 2: Timing Diagram: Power-Up
~
CCTP
V
t
RPU
CCTP
(MAX)
V
OH
Figure 1: RESET Valid to 0V V
Output Conditions
The ASM1810 active LOW reset signal is valid as long as V
remains above 1.2V. However the RESET output on the
ASM1810 uses a push-pull drive stage that can maintain a valid
output below 1.2V. To sink current with V
resistor can be connected from the reset pin (RESET) to
Ground (see Figure 1). This configuration will give a valid value
on the RESET
power up and down, this configuration will draw current when
the RESET is in the high state. A value of 100kΩ should be
adequate to maintain a valid connection.
output with VCC approaching 0V. During both
CC
below 1.2V, a
CC
CC
t
V
CCTP
F
t
RPD
V
OL
V
CC
V
(MAX)
CCTP
RESET
Figure 3: Timing Diagram: Power-Down
V
CCTP
(MIN)
~
~
Low Power, 5V µP Reset
Notice: The information in this document is subject to change without notice
3 of 9
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