February 2005
rev 1.4
ASM1816
Low Power 3.3V/3.0V µP Reset, Active LOW, Open-Drain Output
Applications
•
•
•
•
•
•
•
Set-top boxes
Cellular phones
PDAs
Energy management systems
Embedded control systems
Printers
Single board computers
General Description
The ASM1816 is a voltage supervisory device with low-power,
3.3V/3V µP Reset, active LOW, open-drain output. Maximum
supply current over temperature is a low 15µA (at 3.6V).
The ASM1816 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.
Tolerance level options are 5%, 10% and 20%. 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 150ms to allow the power supply and system
microprocessor to stabilize.
Typical Application
V
CC
ASM1816
The ASM1816 is designed with a open-drain output stage and
operates over the extended industrial temperature range.
Devices are available in TO-92 and compact surface mount
SOT-23 packages.
Other low power products in this family include the ASM1810/
11/12/15/17, ASM1233D and ASM1233M.
RESET
Microprocessor
RESET
GND
Key Features
•
Low Supply Current
•20 µA maximum (5.5 V)
•15µA maximum (3.6 V)
•
•
•
•
•
•
•
Automatically restarts a microprocessor after power failure
150ms 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
TO-92 and compact surface mount SOT-23 package
Operating temperature -40°C to +85°C
Block Diagram
V
CC
2
Supply
Tolerance
Bias
ASM1816
5.0K
Ω
1
RESET
+
-
Reference
Delay
150ms
Typical
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
ASM1816
V
CC
V
CCTP
(MAX)
t
F
Application Information
Operation - Power Monitor
The
ASM1816
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
When an out-of-tolerance V
CC
voltage is detected, the
RESET signal is asserted. On power-up, RESET is kept
active (LOW) for approximatley 150ms after the power supply
voltage has reached the selected tolerance. This allows the
power supply and microprocessor to stablize before RESET
is released.
t
R
V
CCTP
(MAX)
V
CCTP
(MIN)
V
CCTP
V
CCTP
V
CCTP
(MIN)
RESET
t
RPD
V
OL
Figure 2: Timing Diagram: Power-Down
V
CC
t
RPU
V
OH
RESET
Figure 1: Timing Diagram: Power-Up
~
~
3 of 9
monitored power supply voltage is below the reset threshold.
~
~
~
~
Low Power 3.3V/3.0V µP Reset
Notice: The information in this document is subject to change without notice
February 2005
rev 1.4
ASM1816
Absolute Maximum Ratings
Parameter
Voltage on V
CC
Voltage on RESET
Operating Temperature Range
Soldering Temperature (for 10 sec)
Storage Temperature
-55
Min
-0.5
-0.5
-40
Max
7
V
CC
+ 0.5
85
260
125
Unit
V
V
°C
°C
°C
ESD rating
HBM
MM
2
200
KV
V
NOTE: These are stress ratings only and functional use is not implied. Exposure to absolute maximum rat-
ings for prolonged periods of time may affect device reliability.
Electrical Characteristics
Unless otherwise noted, V
CC
= 1.2V to 5.5V and specifications are over the operating temperature range of -40°C to +85°C. All voltages are referenced to
ground
Parameter
Supply Voltage
Output Current
Operating Current
Operating Current
V
CC
Trip Point (ASM1816R-5)
V
CC
Trip Point (ASM1816R-10)
V
CC
Trip Point (ASM1816R-20)
Internal Pull-up Resistor
Output Capacitance
V
CC
Detect to RESET Low
V
CC
Slew Rate
(V
CCTP
(MAX) to V
CCTP
(MIN)
V
CC
Slew Rate
(V
CCTP
(MIN) to V
CCTP
(MAX)
V
CC
Detect to RESET High
Symbol
V
CC
I
OL
I
CC
I
CC
V
CCTP
V
CCTP
V
CCTP
R
P
C
OUT
t
RPD
t
F
t
R
t
RPU
t
r
= 5µs
Conditions
Min
1.2
Typ
Max
5.5
Unit
V
mA
Output = 0.4V, V
CC
> 2.7V
V
CC
< 5.5V, RESET output open
V
CC
< 3.6V, RESET output open
+10
8
6
2.98
2.80
2.47
3.5
3.06
2.88
2.55
5.5
20
15
3.15
2.97
2.64
7.5
10
2
300
0
100
150
250
5
µA
µA
V
V
V
kΩ
pF
µs
µs
ns
ms
Note: The t
F
value is for reference in defining values for t
RPD
and should not be considered for proper operation or use.
Low Power 3.3V/3.0V µP Reset
Notice: The information in this document is subject to change without notice
4 of 9
Embedded System
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