ALSC ASM1232LPF 5v up power supply monitor and reset circuit Datasheet

ASM1232LP/LPS
January 2005
rev 1.5
5V µP Power Supply Monitor and Reset Circuit
General Description
•
Low-cost surface mount packages: 8-pin/16-pin SO, 8-pin
DIP and 8-pin Micro SO packages
The ASM1232LP/LPS is a fully integrated microprocessor
•
supervisor. It can halt and restart a “hung-up” microprocessor,
Wide operating temperature -40°C to +85°C (N suffixed
devices)
restart a microprocessor after a power failure. It has a
watchdog timer and external reset override.
Applications
and
•
Microprocessor Systems
comparator circuits monitor the 5V, VCC input voltage status.
•
Computers
During power-up or when the VCC power supply falls outside
selectable tolerance limits, both RESET and RESET become
•
Controllers
•
Portable Equipment
•
Intelligent Instuments
•
Automotive Systems
A
precision
temperature-compensated
reference
active. When VCC rises above the threshold voltage, the reset
signals remain active for an additional 250ms minimum,
allowing the power supply and system microprocessor to
Typical Operating Circuit
stabilize. The trip point tolerance signal, TOL, selects the trip
level tolerance to be either 5% or 10%.
+5V
Each device has both a push-pull, active HIGH reset output
and an open drain active LOW reset output. A debounced
manual reset input, PBRST, activates the reset outputs for a
10kΩ
ASM1232LP/LPS
minimum period of 250ms.
I/O
ST
There is a watchdog timer to stop and restart a microprocessor
RESET
that is “hung-up”. The watchdog timeouts periods are
selectable: 150ms, 610ms and 1200ms. If the ST input is not
GND
TD
µP
RESET
TOL
strobed LOW before the time-out period expires, a reset is
generated.
Devices are available in 8-pin DIP, 16-pin SO and compact 8-
Block Diagram
pin MicroSO packages.
ASM1232LP/LPS
Key Features
VCC
5V supply monitor
•
Selectable watchdog period
•
Debounce manual push-button reset input
•
+
Reference
40kΩ
•
Power-up, power-down and brown out detection
•
250ms minimum reset time
•
Active LOW open drain reset output and active HIGH
push-pull output
Selectable trip point tolerance: 5% or 10%
RESET
-
VCC
Precision temperature-compensated voltage reference
and comparator.
•
Tolerance Selection
TOL
•
RESET
PBRST
Push Button
Debounce
TD
Voltage Sense
Comparators
ST
Watchdog Transition
Detector
Reset &
Watchdog Timer
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
ASM1232LP/LPS
January 2005
rev 1.5
Pin Configuration
DIP/SO/MicroSO
PBRST
1
TD
2
TOL
3
GND
4
ASM1232LP
ASM1232LPS-2
ASM1232LPU
SO
8
VCC
NC
7
ST
PBRST 2
16 NC
1
6
RESET
NC
3
5
RESET
TD
4
NC
15 VCC
14
NC
13
ST
5
12
NC
TOL
6
11
RESET
NC
7
10
NC
GND
8
9
ASM1232LPS
RESET
Pin Description
Pin #
8-Pin Package
Pin #
16-Pin Package
Pin
Name
1
2
PBRST
2
4
TD
3
6
TOL
4
8
GND
Function
Debounced manual pushbutton RESET input.
Watchdog time delay selection. (tTD = 150ms for TD = GND, tTD = 610ms
for TD=Open, and tTD = 1200ms for TD = VCC).
Selects 5% (TOL connected to GND) or 10% (TOL connected to VCC)
trip point tolerance.
Ground.
Active HIGH reset output. RESET is active:
1. If VCC falls below the reset voltage trip point.
5
9
RESET
2. If PBRST is LOW.
3. If ST is not strobed LOW before the timeout period set by TD expires.
4. During power-up.
6
11
RESET
Active LOW reset output. (See RESET).
7
13
ST
Strobe input.
8
15
VCC
5V power.
-
1,3,5,7,
10,12,14,16
NC
No internal connection.
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
2 of 10
ASM1232LP/LPS
January 2005
rev 1.5
Detailed Description
tR
The ASM1232LP/LPS monitors the microprocessor or
VCCTP(MAX)
VCCTP
microcontroller power supply and generates reset signal,
both active HIGH and Active LOW, that halt processor
VCCTP(MIN)
~~
operation whenever the power supply voltage levels are
outside a predetermined tolerance.
tRPU
VCC
RESET
RESET and RESET outputs
VOH
RESET is an active HIGH signal developed by a CMOS
push-pull output stage and is the logical opposite to RESET.
~
~~~
RESET is an active LOW signal. It is developed with an open
drain driver. A pull up resistor of typical value 10kΩ to 50kΩ is
required to connect with the output.
VOL
RESET
Figure 1: Timing Diagram : Power Up
Trip Point Tolerance Selection
The TOL input is used to determine the level VCC can vary
below 5V without asserting a reset. With TOL conected to
VCC, RESET and RESET become active whenever VCC falls
tF
VCC
VCCTP (MAX)
VCCTP
below 4.5V. RESET and RESET become active when the
VCCTP (MIN)
After VCC has risen above the trip point set by TOL, RESET
~~
VCC falls below 4.75V if TOL is connected to ground.
RESET
tRPD
and RESET remain active for a minimum time period of
250ms. On power-down, once VCC falls below the reset
less until VCC drops below 1.2V. The active HIGH reset signal
Tolerance
RESET
Figure 2: Timing Diagram : Power Down
is valid down to a VCC level of 1.2V also.
Tolerance
Select
VOL
~ ~~
VOH
threshold RESET stays LOW and is guaranteed to be 0.4V or
TRIP Point Voltage
(V)
Min
Nom
Max
TOL = VCC
10%
4.25
4.37
4.49
TOL = GND
5%
4.5
4.62
4.74
Application Information
Manual Reset Operation
Push-button switch input, PBRST, allows the user to override
the internal trip point detection circuits and issue reset
signals. The pushbutton input is debounced and is pulled
HIGH through an internal 40kΩ resistor.
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
3 of 10
ASM1232LP/LPS
January 2005
rev 1.5
When PBRST is held LOW for the minimum time tPB, both
power-up after the supply voltage returns to an in-tolerance
resets become active and remain active for a minimum time
condition, the reset signal remains active for 250ms
period of 250ms after PBRST returns HIGH.
minimum,
allowing
the
power
supply
and
system
microprocessor to stabilize. ST pulses as short as 20ns can
The debounced input is guaranteed to recognize pulses
be detected.
greater than 20ms. No external pull-up resistor is required,
Valid
Strobe
since PBRST is pulled HIGH by an internal 40kΩ resistor.
Valid
Strobe
Invalid
Strobe
ST
tST
The PBRST can be driven from a TTL or CMOS logic line or
tRST
shorted to ground with a mechanical switch.
tTD (min)
~
tTD (max)
tPB
PBRST
RESET
Note: ST is ignored whenever a reset is active
VIH
tPDLY
Figure 5: Timing Diagram: Strobe Input
VIL
~
~~
RESET
RESET
Timeouts periods of approximately 150ms, 610ms or
tRST
1,200ms are selected through the TD pin.
VOH
VOL
Watchdog Time-out Period
(ms)
TD Voltage level
Min
Nom
Max
GND
62.5
150
250
Floating
250
610
1000
VCC
500
1200
2000
Figure 3: Timing Diagram: Pushbutton Reset
5V
ASM1232LP/LPS
1
2
3
4
PBRST
TD
VCC 8
ST
TOL
RESET
GND
RESET
7
6
5
The watchdog timer can not be disabled. It must be strobed
I/O
µP
with a high-to-low transition to avoid watchdog timeout and
reset.
RESET
5V
Figure 4: Application Circuit: Pushbutton Reset
ASM1232 LP/LPS
1
2
Watchdog Timer and ST Input
A watchdog timer stops and restarts a microprocessor that is
“hung-up”. The µP must toggle the ST input within a set
period (as selectable through TD input) to verify proper
software execution. If the ST is not toggled low within the
minimum timeout period, reset signals become active. In
3
4
PBRST
TD
TOL
GND
MREQ
VCC 8
ST
RESET
7
6
10kΩ
µP
Decoder
RESET Address
5
Bus
Figure 6: Application Circuit: Watchdog Timer
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
4 of 10
ASM1232LP/LPS
January 2005
rev 1.5
Absolute Maximum Ratings
Parameter
Min
Max
Unit
Voltage on VCC
-0.5
7
V
Voltage on ST, TD
-0.5
VCC + 0.5
V
Voltage on PBRST, RESET, RESET
-0.5
VCC + 0.5
V
Operating Temperature Range (N suffixed devices)
-40
+85
°C
0
70
°C
+260
°C
+125
°C
2
200
KV
V
Operating Temperature Range (others)
Soldering Temperature (for 10 sec)
Storage Temperature
-55
ESD rating
HBM
MM
Note:
1. Voltages are measured with respect to ground
2. These are stress ratings only and functional implication is not implied. Exposure to absolute maximum ratings for extended
periods may affect device reliability.
DC Electrical Characteristics
Unless otherwise stated, 4.5V <= VCC<= 5.5V and over the operating temperature range of 0°C to 70°C (-40°C to +85°C. for N devices). All
voltages are referenced to ground.
Parameter
Symbol
Conditions
Min
Typ
Max
Unit
Supply Voltage
VCC
4.5
5.5
V
ST and PBRST Input High Level
VIH
2
VCC + 0.3
V
ST and PBRST Input Low Level
VIL
-0.3
0.8
V
VCC Trip Point (TOL = GND)
VCCTP
4.50
4.62
4.74
V
VCC Trip Point (TOL = VCC)
VCCTP
4.25
4.37
4.49
V
Watchdog Timeout Period
tTD
TD = GND
62.5
150
250
ms
Watchdog Timeout Period
tTD
TD = VCC
500
1200
2000
ms
Watchdog Timeout Period
tTD
TD Floating
250
610
1000
ms
Output Voltage
VOH
I=-500µA, Note 3
VCC - 0.5
VCC - 0.1
V
Output Current
IOH
Output = 2.4V, Note 2
-8
-10
mA
Output Current
IOL
Output = 0.4V
10
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
mA
5 of 10
ASM1232LP/LPS
January 2005
rev 1.5
Parameter
Symbol
Input Leakage
RESET Low Level
Conditions
IIL
Note 1
VOL
Note 3
Internal Pull-up Resistor
Min
Typ
-1.0
Note 1
Max
Unit
1.0
µA
0.4
V
40
kΩ
Operating Current (CMOS)
ICC1
30
µA
Input Capacitance
CIN
5
pF
COUT
10
pF
Output Capacitance
PBRST Manual Reset
Minimum Low Time
tPB
Reset Active Time
tRST
ST Pulse Width
tST
VCC Fail Detect to RESET or
VCC Slew Rate
tF
PBRST Stable LOW to RESET and
RESET Active
VCC Detect to RESET or RESET
VCC Slew Rate
20
250
Note 4
ms
610
tR
tRISE = 5µs
4.25V to 4.75V
8
300
250
0
µs
µs
tPDLY
tRPU
ms
ns
5
4.75V to 4.25V
1000
20
tRPD
RESET
inactive
PBRST = VIL
610
20
ms
1000
ms
ns
Notes
1. PBRST is internally pulled HIGH to VCC through a nominal 40kΩ resistor.
2. RESET is an open drain output.
3. RESET remains within 0.5V of VCC on power-down until VCC falls below 2V. RESET remains within 0.5V of ground on power-down until VCC
falls below 2.0V.
4. Must not exceed the minimum watchdog time-out period (tTD). The watchdogcircuit cannot be disabled. To avoid a reset, ST must be strobed.
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
6 of 10
ASM1232LP/LPS
January 2005
rev 1.5
Package Information
MicroSO (8-Pin)
Inches
Millimeteres
Min
Max
Min
Max
MicroSO (8-Pin)
A
0.032
0.044
0.81
1.10
A1
0.002
0.006
0.05
0.15
A2
0.030
0.038
0.76
0.97
b
0.012 BSC
0.004
0.008
0.10
D
0.114
0.122
2.90
e
0.0256 BSC
0.20
3.10
0.65 BSC
E
0.184
0.200
4.67
5.08
E1
0.114
0.122
2.90
3.10
L
0.016
0.026
0.41
S
a
0.0206 BSC
0°
0.66
0.52 BSC
6°
0°
6°
SO (8-Pin)
SO (8-Pin)
H
E
A
0.053
0.069
1.35
1.75
A1
0.004
0.010
0.10
0.25
A2
0.049
0.059
1.25
1.50
B
0.012
0.020
0.31
0.51
C
0.007
0.010
0.18
D
D
0.193 BSC
A
C
A1
B
Plastic DIP (8-Pin)
D
θ
L
0.25
4.90 BSC
E
0.154 BSC
3.91 BSC
e
0.050 BSC
1.27 BSC
H
A2
e
0.30 BSC
C
0.236 BSC
L
0.016
θ
0°
6.00 BSC
0.050
0.41
1.27
8°
0°
8°
Plastic DIP (8-Pin)
A
-
0.210
-
5.33
A1
0.015
-
0.38
-
A2
0.115
0.195
2.92
4.95
b
0.014
0.022
0.36
0.56
b2
0.045
0.070
1.14
1.78
C
0.008
0.014
0.20
0.36
D
0.355
0.400
9.02
10.16
E
0.300
0.325
7.62
8.26
E1
0.240
0.280
6.10
e
0.100 BSC
7.11
2.54 BSC
eB
-
0.430
-
10.92
L
0.115
0.150
2.92
3.81
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
7 of 10
ASM1232LP/LPS
January 2005
rev 1.5
SO (16-Pin)
PIN 1 ID
1
8
E
9
H
16
D
A2
D
A
e
h
Seating Plane
C
θ
0.004
L
A1
B
SO (16-Pin)*
Inches
Millimeter
Min
Max
Min
Max
A
0.053
0.069
1.35
1.75
A1
0.004
0.010
0.10
0.25
A2
0.049
0.059
1.25
1.50
B
0.013
0.022
0.33
0.53
C
0.008
0.012
0.19
0.27
D
0.386
0.394
9.80
10.01
E
0.150
0.157
3.80
4.00
e
0.050 BSC
1.27 BSC
H
0.228
0.244
5.80
6.20
h
0.010
0.016
0.25
0.41
L
0.016
0.035
0.40
0.89
θ
0°
8°
0°
8°
* JEDEC Drawing MS-013AA
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
8 of 10
ASM1232LP/LPS
January 2005
rev 1.5
Ordering Information
Package
Operating
Temperature
Range
Maximum
Supply
Current (µA)
Voltage
Monitoring
Application
Package Marking
ASM1232LP
8L PDIP
0°C to +70°C
30
5V
ASM1232LP
ASM1232LPN
8L PDIP
-40° C to +85°C
30
5V
ASM1232LPN
ASM1232LPS
16L SOIC
0°C to +70°C
30
5V
ASM1232LPS
ASM1232LPS-2
8L SOIC
0°C to +70° C
30
5V
ASM1232LPS-2
ASM1232LPSN
16L SOIC
-40°C to +85°C
30
5V
ASM1232LPSN
ASM1232LPSN-2
8L SOIC
-40°C to +85°C
30
5V
ASM1232LPSN-2
ASM1232LPU
8L MSOP
0°C to +70°C
30
5V
ASM1232LP
ASM1232LPUN
8L MSOP
-40°C to +85°C
30
5V
ASM1232LPN
ASM1232LPF
8L PDIP
0°C to +70°C
30
5V
ASM1232LPF
ASM1232LPNF
8L PDIP
-40°C to +85°C
30
5V
ASM1232LPNF
ASM1232LPS-2F
8L SOIC
0°C to +70°C
30
5V
ASM1232LPS-2F
ASM1232LPSF
16L SOIC
0°C to +70°C
30
5V
ASM1232LPSF
ASM1232LPSN-2F
8L SOIC
-40°C to +85°C
30
5V
ASM1232LPSN-2F
ASM1232LPSNF
16L SOIC
-40°C to +85°C
30
5V
ASM1232LPSNF
ASM1232LPUF
8L MSOP
0°C to +70°C
30
5V
ASM1232LPF
ASM1232LPUNF
8L MSOP
-40°C to +85°C
30
5V
ASM1232LPNF
Part Number
TIN-LEAD DEVICES
LEAD FREE DEVICES
5V µP Power Supply Monitor and Reset Circuit
Notice: The information in this document is subject to change without notice
9 of 10
ASM1232LP/LPS
Alliance Semiconductor Corporation
2575, Augustine Drive,
Santa Clara, CA 95054
Tel: 408 - 855 - 4900
Fax: 408 - 855 - 4999
www.alsc.com
Copyright © Alliance Semiconductor
All Rights Reserved
Part Number: ASM1232LP/LPS
Document Version: 1.5
© Copyright 2003 Alliance Semiconductor Corporation. All rights reserved. Our three-point logo, our name and Intelliwatt are trademarks or
registered trademarks of Alliance. All other brand and product names may be the trademarks of their respective companies. Alliance reserves the
right to make changes to this document and its products at any time without notice. Alliance assumes no responsibility for any errors that may appear
in this document. The data contained herein represents Alliance's best data and/or estimates at the time of issuance. Alliance reserves the right to
change or correct this data at any time, without notice. If the product described herein is under development, significant changes to these
specifications are possible. The information in this product data sheet is intended to be general descriptive information for potential customers and
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