February 2005
rev 1.5
ASM1817
Low Power, 3.3V/3.0V µP Reset, Active HIGH, Push-Pull Output
Applications
•
•
•
•
•
•
•
Set-top boxes
Cellular phones
PDAs
Energy management systems
Embedded control systems
Printers
Single board computers
General Description
The ASM1817 voltage supervisory device with low-power, 3.3V/
3.0V µP Reset, active HIGH, Push-Pull output. Maximum
supply current over temperature is a low 15µA (at 3.6V).
The ASM1817 generates an active HIGH 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% percent. When
an out-of-tolerance condition is detected, an internal power-fail
signal is generated which forces an active HIGH 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 Operating Circuit
V
CC
ASM1817
The ASM1817 is designed with a push-pull 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/
11/12/15/16, ASM1233D and ASM1233M.
RESET
RESET
Microprocessor
GND
Key Features
•
Low Supply Current
•20 µA maximum (5.5 V)
•15 µA 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 HIGH power-up reset
Precision temperature-compensated voltage reference and
comparator
Eliminates external components
TO-92 and compact surface mount SOT-23 package
Push-Pull output for minimum current drain
Operating temperature -40°C to +85°C
Block Diagram
V
CC
Supply
Tolerance
Bias
ASM1817
+
Delay
150ms
Typical
-
Reference
RESET
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 1.5
ASM1817
Application Information
Operation - Power Monitor
The
ASM1817
detects
out-of-tolerance
power
supply
V
CCTP
(MIN)
t
R
V
CCTP
(MAX)
V
CCTP
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
CC
voltage is detected, the
RESET signal is asserted. On power-up, RESET is kept
active (HIGH) 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.
RESET
V
CC
~
~
~
~
t
RPU
V
OL
ASM1817
Microprocessor
RESET
RESET
Figure 2: Timing Diagram: Power-Up
V
CC
tF
V
CCTP
(MAX)
V
CCTP
Figure 1: Typical Application
V
CCTP
(MIN)
~
~
t
RPD
V
OH
RESET Slews with V
CC
~
~
RESET
Figure 3: Timing Diagram: Power-Down
Low Power, 3.3V/3.0V µP Reset
Notice: The information in this document is subject to change without notice
3 of 9
February 2005
rev 1.5
ASM1817
Absolute Maximum Ratings
Parameter
Voltage on V
CC
Voltage on RESET
Operating Temperature Range
Soldering Temperature (for 10 sec)
Storage Temperature
ESD rating
HBM
MM
2
200
KV
V
-55
Min
-0.5
-0.5
-40
Max
7
V
CC
+ 0.5
85
260
125
Unit
V
V
°C
°C
°C
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 Voltage
Output Current
Output Current
Operating Current
Operating Current
V
CC
Trip Point (ASM1817R-5)
V
CC
Trip Point (ASM1817R-10)
V
CC
Trip Point (ASM1817R-20)
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
V
OH
I
OH
I
OL
I
CC
I
CC
V
CCTP
V
CCTP
V
CCTP
C
OUT
t
RPD
t
F
t
R
t
RPU
t
r
= 5µs
Conditions
Min
1.2
Typ
Max
5.5
Unit
V
V
µA
mA
I
OUT
< 500 µA
Output = 2.4V, V
CC
> 2.7V
Output = 0.4V, V
CC
> 2.7V
V
CC
< 5.5V, RESET output open
V
CC
< 3.6V, RESET output open
V
CC
- 0.5V
V
CC
- 0.1V
350
+10
8
6
2.98
2.80
2.47
3.06
2.88
2.55
20
15
3.15
2.97
2.64
10
2
300
0
100
150
250
5
µA
µA
V
V
V
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
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