May 2005
rev 1.7
ASM8500
Low Power 5V / 3.3V µP Reset Active LOW, Open - Drain Output
•
•
Printers
Single board computers
General Description
The ASM8500 is a voltage supervisory device with a low-power,
5V
/
3.3V µP Reset, active LOW, open-drain output. Typical
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 ±1.7% at room temperature. 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 and 3-
lead TO-92 packages.
Other low power products in this family include the ASM1810/
11/12/15/16/17 and ASM1233D/M.
Typical Operating Circuit
V
CC
ASM8500
Microprocessor
RESET
RESET
GND
Block Diagram
V
CC
Key Features
•
•
•
•
•
•
•
•
Low Supply Current
• 6 µA typical (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 and TO-92 packages
Operating temperature -40°C to +85°C
Supply
Tolerance
Bias
ASM8500
5.5ΚΩ
RESET
+
-
Reference
Delay
1.5ms
Typical
GND
Applications
•
•
•
•
•
Set-top boxes
Cellular phones
PDAs
Energy management systems
Embedded control systems
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
May 2005
ASM8500
rev 1.7
Pin Configuration
SOT-89
ASM8500
1
TO- 92
ASM8500-25
2
3
V
CC
GND
RESET
1
2
3
Pin Description
Pin #
1
2
3
Pin Name
V
CC
GND
RESET
Description
Power supply input
Ground
Active LOW reset output
Low Power 5V / 3.3V µP Reset Active LOW, Open - Drain Output
Notice: The information in this document is subject to change without notice
2 of 9
May 2005
rev 1.7
ASM8500
Application Information
Operation - Power Monitor
The
ASM8500
detects
out-of-tolerance
power
supply
V
CC
V
CCTP
(MAX)
V
CCTP
V
CCTP
(MIN)
t
F
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
voltage has reached the selected tolerance. This allows the
power supply and microprocessor to stabilize before RESET
is released.
RESET
t
RPD
t
R
V
CCTP
(MAX)
V
CCTP
(MIN)
V
CCTP
V
OL
Figure 2: Timing Diagram: Power-Down
V
CC
t
RPU
V
OH
RESET
Figure 1: Timing Diagram: Power-Up
~
~
3 of 9
active (LOW) for approximately 1.5ms after the power supply
~
~
~
~
Low Power 5V / 3.3V µP Reset Active LOW, Open - Drain Output
Notice: The information in this document is subject to change without notice
May 2005
ASM8500
rev 1.7
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
-55
Min
-0.5
-0.5
-40
Max
7
V
CC
+ 0.5
85
260
125
2
200
Unit
V
V
°C
°C
°C
KV
V
NOTE: These are stress ratings only and functional use is not implied. Exposure to absolute maximum ratings 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
Operating Current
Symbol
V
CC
V
OL
I
OL
I
CC
Conditions
Min
1
Typ
Max
5.5
Unit
V
V
mA
RESET asserted ( V
CC
>= 4.5V
I
SINK
= 3.2 mA)
Output = 0.4V
V
CC
< 5.5V, RESET output open
ASM8500-45
ASM8500-42
ASM8500-39
ASM8500-29
ASM8500-27
ASM8500-25
-
+10
-
0.4
6
4.388
4.095
3.803
2.857
2.633
2.438
3.5
4.5
4.2
3.9
2.93
2.7
2.5
5.0
4.613
4.305
3.998
3.003
2.768
2.563
7.5
10
0.5
1.5
2
300
0
5
5
µA
V
CC
Trip Point
V
CCTP
V
Internal Pull-up Resistor
Output Capacitance
RESET Active Time
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
R
P
C
OUT
t
RESET
t
RPD
t
F
t
R
t
RPU
t
r
= 5µs
kΩ
pF
ms
µs
µs
ns
0.5
1.5
5
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 5V / 3.3V µP Reset Active LOW, Open - Drain Output
Notice: The information in this document is subject to change without notice
4 of 9
May 2005
ASM8500
rev 1.7
Ordering Information
Part #
**
TIN-LEAD DEVICES
ASM8500EUR-45
ASM8500EUR-42
ASM8500EUR-29
ASM8500EUR-27
ASM8500EUR-39
ASM8500EUR-25
ASM8500EZR-45
ASM8500EZR-42
ASM8500EZR-29
ASM8500EZR-27
ASM8500EZR-39
ASM8500EZR-25
LEAD FREE DEVICES
ASM8500EUR-45F
ASM8500EUR-42F
ASM8500EUR-29F
ASM8500EUR-27F
ASM8500EUR-39F
ASM8500EUR-25F
ASM8500EZR-45F
ASM8500EZR-42F
ASM8500EZR-29F
ASM8500EZR-27F
ASM8500EZR-39F
ASM8500EZR-25F
4.5
4.2
2.93
2.7
3.9
2.5
4.5
4.2
2.93
2.7
3.9
2.5
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
SOT-89
SOT-89
SOT-89
SOT-89
SOT-89
SOT-89
TO-92
TO-92
TO-92
TO-92
TO-92
TO-92
J6LL
J1LL
J2LL
J3LL
J4LL
J5LL
ASM8500EZR-45F
ASM8500EZR-42F
ASM8500EZR-29F
ASM8500EZR-27F
ASM8500EZR-39F
ASM8500EZR-25F
4.5
4.2
2.93
2.7
3.9
2.5
4.5
4.2
2.93
2.7
3.9
2.5
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
-40°C to 85°C
SOT-89
SOT-89
SOT-89
SOT-89
SOT-89
SOT-89
TO-92
TO-92
TO-92
TO-92
TO-92
TO-92
U6LL
U1LL
U2LL
U3LL
U4LL
U5LL
ASM8500EZR-45
ASM8500EZR-42
ASM8500EZR-29
ASM8500EZR-27
ASM8500EZR-39
ASM8500EZR-25
RESET Voltage (V)
Temperature Range
Package
Package Marking
(LL Lot Code)
Notes:
•
For parts to be packed in Tape and Reel, add “-T” at the end of the part number.
•
Alliance Semiconductor's lead free parts are RoHS complaint.
Low Power 5V / 3.3V µP Reset Active LOW, Open - Drain Output
Notice: The information in this document is subject to change without notice
5 of 9
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