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October 2003
rev 1.0
ASM811, ASM812
4 Pin P Voltage Supervisor with Manual Reset
Six voltage thresholds are available to support 3V to 5V systems:
General Description
The ASM811/ASM812 are cost effective low power supervisors designed to monitor voltage levels of 3.0V, 3.3V and 5.0V power supplies in low-power microprocessor (P), microcontroller (C) and digital systems. They provide excellent reliability by eliminating external components and adjustments. A reset signal is issued if the power supply voltage drops below a preset reset threshold and is asserted for at least 140ms after the supply has risen above the reset threshold. The ASM811 has an active-low output RESET that is guaranteed to be in the correct state for VCC down to 1.1V. The ASM812 has an activehigh RESET output. The reset comparator is designed to ignore fast transients on VCC. A debounced manual reset input allows the user to manually reset the systems to bring them out of locked state. Low power consumption makes the ASM811/ASM812 ideal for use in portable and battery operated equipment. The ASM811/ ASM812 are available in a compact 4-pin SOT-143 package and thus use minimal board space.
RESET THRESHOLD Suffix L M J T S R Voltage 4.63 4.38 4.00 3.08 2.93 2.63
Features
* * * * * * * * * * New 4.0V threshold option 9A supply current Monitor 5V, 3.3V and 3V supplies Manual reset input 140ms min. reset pulse width Guaranteed over temperature Active-low reset valid with 1.1V supply (ASM811) Small 4-pin SOT-143 package No external components Power-supply transient-immune design
Applications
* * * * * * * * Computers and Controllers Embedded controllers Portable/Battery operated systems Intelligent instruments Wireless communication systems PDAs and handheld equipment Automotive systems Safety Systems
Typical Operating Circuit
VCC
VCC VCC P MR RESET (RESET) GND RESET (RESET) Input 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
October 2003
rev 1.0
ASM811, ASM812
SOT143
GND 1 ASM811 (ASM812)
Pin Diagram:
Block Diagram
4 VCC
VCC
20k
MR VCC
3 MR
(RESET) RESET
2
+ + -
RESET Generator
4.63V 4.38V 4.38V 4.00V 3.08V 2.93V 2.63V
RESET (RESET)
ASM811 (ASM812)
Pin Description
GND
Pin # ASM811 1 2 ASM812 1 -
Pin Name GND RESET Ground.
Function
RESET is asserted LOW if VCC falls below VTH and remains LOW for TRST after VCC exceeds the Threshold. In addition, RESET is active LOW as long as the manual reset is low. RESET is asserted HIGH if VCC falls below VTH and remains HIGH for TRST after VCC exceeds the threshold. In addition, RESET is active HIGH as long as the manual reset is low. Manual Reset Input. A logic LOW on MR asserts reset. Reset remains active as long as MR is LOW and for TMRST after MR returns HIGH. The active low input has an internal 20k pull-up resistor. The input should be left open if not used. It can be driven by TTL or CMOS logic or shorted to ground by a switch. Power supply input voltage (3.0V, 3.3V, 5.0V)
-
2
RESET
3
3
MR
4
4
VCC
Detailed Description
Manual Reset (MR) Input A proper reset input enables a microprocessor / A logic low on MR assserts RESET LOW on the ASM811 and RESET HIGH on the ASM812. MR is internally pulled high through a 20k resistor and can be driven by TTL/CMOS gates or with open collector/drain outputs. MR can be left open if not used. MR may be connected to ground through a normallyopen momentary switch without an external debounce circuit. A 0.1F capacitor from MR to ground can be added for additional noise immunity.
microcontroller to start in a known state. ASM811/812 assert reset to prevent code execution errors during power-up, powerdown and brown-out conditions. Reset Timing The reset signal is asserted- LOW for the ASM811 and HIGH for the ASM812- when the VCC supply voltage falls below the threshold trip voltage and remains asserted for 140ms minimum after the VCC has risen above the threshold.
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
2 of 10
October 2003
rev 1.0
5V 0V
TRST MR
Power Supply
MR
ASM811, ASM812
VCC
VTH
VCC
VCC
100k
ASM811
RESET GND 100k
Power Supply
ASM812
MR
RESET GND
5V 0V
TMRST
5V RESET 0V
RESET
ASM811 ASM812
5V 0V
Figures 2 & 3: RESET valid with VCC under 1.1V
Figure 1: Reset Timing and Manual Reset (MR)
Application Information
Reset Output Operation In P / C systems it is important to have the processor and the system begin operation from a known state. A reset output to a processor is provided to prevent improper operation during power supply sequencing or low voltage brown-out conditions. Bidirectional Reset Pin Interfacing The ASM811/812 are designed to monitor the system power supply voltages and issue a reset signal when the levels are out of range. RESET outputs are guaranteed to be active for VCC above 1.1V. When VCC exceeds the reset threshold, an internal timer keeps RESET active for the reset timeout period, after which RESET becomes inactive (HIGH for the ASM811 and LOW for the ASM812). If VCC drops below the reset threshold, RESET automatically becomes active. Alternatively, external circuitry or an operator can initiate this condition using the Manual Reset (MR) pin. MR can be left open if it is not used. MR can be driven by TTL/CMOS logic or even an external switch. Valid Reset with VCC under 1.1V To ensure logic inputs connected to the ASM811 RESET pin are in a known state when VCC is under 1.1V, a 100k pulldown resistor at RESET is needed. The value is not critical. A 100k pull-up resistor to VCC is needed with the ASM812.
Bi-directional I/O Pin Power supply VCC
Negative VCC Transients Typically short duration transients of 100mV amplitude and 20s duration do not cause a false RESET. A 0.1F capacitor at VCC increses transient immunity.
The ASM811/812 can interface with P / C bi-directional reset pins by connecting a 4.7k resistor in series with the ASM811/812 reset output and the P/C bi-directional reset input pin.
BUF Buffered RESET
ASM811
4.7k
C or P RESET Input GND
MR
RESET GND
Figure 4: Bi-directional Reset Pin Interface
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
3 of 10
October 2003
rev 1.0
ASM811, ASM812
Absolute Maximum Ratings, Table 1:
Parameter Pin Terminal Voltage With Respect To Ground VCC RESET, RESET and MR Input current at VCC and MR Output current: RESET, RESET Rate of Rise at VCC
Min
Max
Units
-0.3 -0.3
6.0 VCC + 0.3 20 20 100
V V mA mA V/s
Note: These are stress ratings only and the functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
Absolute Maximum Ratings, Table 2:
Parameter Power Dissipation (TA = 70C) Derate SOT-143 4mW/C above 70C Operating temperature range Storage temperature range Lead temperature (Soldering, 10 sec) -40 -65 Min Max 320 105 160 300 Units uW C C C
Note: These are stress ratings only and the functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
4 of 10
October 2003
rev 1.0
ASM811, ASM812
Electrical Characteristics:
Unless otherwise noted, VCC is over the full voltage range, TA = -40C to 105C. Typical values at TA = 25C, VCC = 5V for L/M/J devices, VCC = 3.3V for T/S devices and VCC = 3V for R devices.
Symbol
VCC
Parameter
Input Voltage Range
Conditions
TA = 0C to 70C TA = -40C to 105C TA= -40C to 85C TA = -40C to 85C TA = 85C to 105C TA = 85C to 105C VCC < VCC < VCC < VCC < 5.5V, L/M/J 3.6V, R/S/T 5.5V, L/M/J 3.6V, R/S/T
Min
1.1 1.2
Typ
Max
5.5 5.5
Unit
V V
ICC
Supply Current (Unloaded)
9 6.8
15 10 25 20 4.70 4.75 4.86 4.45 4.50 4.56 4.06 4.10 4.20
A
L devices
TA = 25C TA = -40C to 85C TA = 85C to 105C TA = 25C TA = -40C to 85C TA = 85C to 105C TA = 25C TA = -40C to 85C TA = 85C to 105C TA = 25C TA = -40C to 85C TA = 85C to 105C TA = 25C TA = -40C to 85C TA = 85C to 105C TA = 25C TA = -40C to 85C TA = 85C to 105C
4.56 4.50 4.40 4.31 4.25 4.16 3.93 3.89 3.80 3.04 3.00 2.92 2.89 2.85 2.78 2.59 2.55 2.50
4.63
M devices
4.38
J devices VTH Reset Threshold T devices
4.00
V 3.08 3.11 3.15 3.23 2.96 3.00 3.08 2.66 2.70 2.76 ppm/C s 560 240 840 ms
S devices
2.93
R devices
2.63
TCVTH
Reset Threshold Temp. Coefficient VCC to Reset Delay VCC = VTH to (VTH - 125mV), TA = 0C to 70C Reset Active Timeout Period TA = -40C to 105C 140 100 10
30 60
tMR
MR Minimum Pulse Width
s
Notes: 1. Production testing done at TA = 25C. Over-temperature specifications guaranteed by design only using six sigma design limits. 2. RESET output is active LOW for the ASM811 and RESET output is active HIGH for the ASM812. 3. Glitches of 100ns or less typically will not generate a reset pulse.
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
5 of 10
October 2003
rev 1.0
Symbol Parameter
MR Glitch Immunity tMD VIH VIL VIH VIL MR Pullup Resistance VCC= VTH min., ISINK = 1.2mA, ASM811R/S/T VOL Low RESET Output Voltage (ASM811) VCC= VTH min., ISINK = 3.2mA, ASM811L/M/J VCC > 1.1V, ISINK = 50A VCC > VTH max., ISOURCE = 500A, ASM811R/S/T VCC > VTH max., ISOURCE = 800A, ASM811L/M/J VCC= VTH max., ISINK = 1.2mA, ASM812R/S/T VCC= VTH max., ISINK = 3.2mA, ASM812L/M/J VOH TRST TMRST High RESET Output Voltage (ASM812) Active Reset Timeout Period Manual Active Reset Timeout Period 1.8V < VCC < VTH min., ISOURCE = 150A VCC > VTH MR returns HIGH 0.8VCC 140 0.8VCC MR Input Threshold MR to RESET Propogation Delay MR Input Threshold
ASM811, ASM812
Conditions
Note 3 Note 2 VCC > VTH (MAX), ASM811/812L/M/J VCC > VTH (MAX), ASM811/812R/S/T 2.3 V 0.8 0.77VCC 0.25VCC 10 20 30 0.3 k
Min
Typ
100 0.5
Max
Unit
ns s
V
0.4
V
0.3
VOH
High RESET Output Voltage (ASM811)
V VCC - 1.5 0.3 V 0.4 V 240 180 msec msec
VOL
Low RESET Output Voltage (ASM812)
Notes: 1. Production testing done at TA = 25C. Over-temperature specifications guaranteed by design only using six sigma design limits. 2. RESET output is active LOW for the ASM811 and RESET output is active HIGH for the ASM812. 3. Glitches of 100ns or less typically will not generate a reset pulse.
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
6 of 10
October 2003
rev 1.0
ASM811, ASM812
Typical Operating Characteristics
Unless otherwise noted, VCC is over the full voltage range, TA = -40C to 105C. Typical values at TA = 25C, VCC = 5V for L/M/J devices, VCC = 3.3V for T/S devices and VCC = 3V for R devices.
Supply Current vs Tem perature 10 Supply Current (A) 8 6 4 2 0 -40 -20 0 20 40 60 80 100 125
ASM811R
ASM811T
Tem perature (C)
Norm alised Reset Threshold vs Tem perature 1.02 1.01 1 0.99 0.98 0.97 0.96 0.95 -40
ASM811T
Normalised Reset Threshold
ASM811R
-20
0
20
40
60
80
100
125
Tem perature (C)
Reset Tim eout Period vs Tem perature 400 350 300 250 200 150 100 50 0 -40
ASM811R
Reset Timeout Period (ms)
ASM811T
-20
0
20
40
60
80
100
125
Tem perature (C)
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
7 of 10
October 2003
rev 1.0
ASM811, ASM812
Package Dimensions:
Plastic SOT-143 (4-Pin)
Inches Min A A1 B B1 C D E e e1 H L 0.031 0.001 0.014 0.030 0.0034 0.105 0.047 0.070 0.071 0.082 0.004 Max 0.047 0.005 0.022 0.038 0.006 0.120 0.055 0.080 0.079 0.098 0.012
Millimeters
B
e1
Min 0.787 0.025 0.356 0.762 0.086 2.667 1.194 1.778 1.803 2.083 0.102
Max 1.194 0.127 0.559 0.965 0.152 3.048 1.397 2.032 2.007 2.489 0.305 A1 e C L A
a = 0 -8
E
H
B1
e D
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
8 of 10
October 2003
rev 1.0
ASM811, ASM812
Ordering Information:
Part Number 1 Reset Threshold (V) Temperature Range Pin-Package Package Marking (XX Lot Code)
ASM811 ACTIVE LOW RESET ASM811LEUS-T ASM811MEUS-T ASM811JEUS-T ASM811TEUS-T ASM811SEUS-T ASM811REUS-T ASM812 ACTIVE HIGH RESET ASM812LEUS-T ASM812MEUS-T ASM812JEUS-T ASM812TEUS-T ASM812SEUS-T ASM812REUS-T 4.63 4.38 4.00 3.08 2.93 2.63 -40C to +105C -40C to +105C -40C to +105C -40C to +105C -40C to +105C -40C to +105C 4-SOT143 4-SOT143 4-SOT143 4-SOT143 4-SOT143 4-SOT143 SSXX STXX SUXX SVXX SWXX SXXX 4.63 4.38 4.00 3.08 2.93 2.63 -40C to +105C -40C to +105C -40C to +105C -40C to +105C -40C to +105C -40C to +105C 4-SOT143 4-SOT143 4-SOT143 4-SOT143 4-SOT143 4-SOT143 SMXX SNXX SOXX SPXX SQXX SRXX
Notes: 1. Tape and Reel packaging is indicated by the -T designation.
Related Products:
ASM809 Max Supply Current Package Pins Manual RESET input Package Type Active-HIGH RESET Output Active-LOW RESET Output SOT - 23 SOT - 23 SOT - 143 SOT - 143 15A 3 ASM810 15A 3 ASM811 15A 4 ASM812 15A 4
4 Pin P Voltage Supervisor with Manual Reset
Notice: The information in this document is subject to change without notice
9 of 10
ASM811, ASM812
Alliance Semiconductor Corporation 2575, Augustine Drive, Santa Clara, CA 95054 Tel: 408 - 855 - 4900 Fax: 408 - 855 - 4999 www.alsc.com
Copyright (c) Alliance Semiconductor All Rights Reserved Part Number: ASM811, ASM812 Document Version: v 1.0
(c) 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 users, and is not intended to operate as, or provide, any guarantee or warrantee to any user or customer. Alliance does not assume any responsibility or liability arising out of the application or use of any product described herein, and disclaims any express or implied warranties related to the sale and/or use of Alliance products including liability or warranties related to fitness for a particular purpose, merchantability, or infringement of any intellectual property rights, except as express agreed to in Alliance's Terms and Conditions of Sale (which are available from Alliance). All sales of Alliance products are made exclusively according to Alliance's Terms and Conditions of Sale. The purchase of products from Alliance does not convey a license under any patent rights, copyrights; mask works rights, trademarks, or any other intellectual property rights of Alliance or third parties. Alliance does not authorize its products for use as critical components in life-supporting systems where a malfunction or failure may reasonably be expected to result in significant injury to the user, and the inclusion of Alliance products in such life-supporting systems implies that the manufacturer assumes all risk of such use and agrees to indemnify Alliance against all claims arising from such use.

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