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ASM705 / 706 / 707 / 708 ASM813L
July 2004
rev 1.2
Low Power P Supervisor Circuits
General Description
The ASM705 / 706 / 707 / 708 and AS813L are cost effective CMOS supervisor circuits that monitor power-supply and battery voltage level, and P/C operation. The family offers several functional options. Each device generates a reset signal during power-up, power-down and during brownout conditions. A reset is generated when the supply drops below 4.65V (ASM705/707/813L) or 4.40V (ASM706/708). For 3V power supply applications, refer to the ASM705P/R/S/T data sheet. In addition, the ASM705/706/813L feature a 1.6 second watchdog timer. The ASM707/708 have both active-HIGH and active-LOW reset outputs but no watchdog function. The ASM813L has the same pin-out and functions as the ASM705 but has an active-HIGH reset output. A versatile power-fail circuit has a 1.25V threshold, useful in low battery detection and for monitoring non-5V supplies. All devices have a manual reset (MR) input. The watchdog timer output will trigger a reset if connected to MR. All devices are available in 8-pin DIP, SO and MicroSO packages. * * * * * *
Features
* Precision power supply monitor *4.65V threshold (ASM705/707/813L) *4.40V threshold (ASM706/708) Debounced manual reset input Voltage monitor *1.25V threshold *Battery monitor / Auxiliary supply monitor Watchdog timer (ASM705/706/813L) 200ms reset pulse width Active HIGH reset output (ASM707/708/813L) MicroSO package
Applications
* * * * * * * Computers and embedded controllers Portable/Battery-operated systems Intelligent instruments Wireless communication systems PDAs and hendheld equipment Automative Systems Safety Systems
Typical Operating Circuit
Unregulated DC
+5V Regulator
R1 VCC PFI RESET (RESET)
VCC
P
RESET (RESET) I/O LINE NMI INTERRUPT
R2
ASM705 WDI ASM706 (ASM813L) WDO PFO
MR
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
July 2004
rev 1.2
ASM705 / 706 / 707 / 708 ASM813L
Block Diagrams
WDI
Transition Detector VCC 0.25mA
Watchdog Timer Timebase RESET Generator
WDO
VCC 0.25mA
RESET
MR
RESET (RESET) ASM813L
MR
RESET Generator
RESET
VCC
+
+ -
VCC
+
+ -
4.65V (ASM705/813L) 4.40V (ASM706)
+
4.65V (ASM707) 4.40V (ASM708)
+
PFI
PFI PFO 1.25V
ASM705 ASM706 ASM813L
1.25V
-
-
PFO
ASM707 ASM708
GND
GND
Pin Configuration
DIP/SO
MR VCC 1 2 ASM707 4 8 RESET 7 RESET 6 5 NC PFO
MicroSO
8 WDO RESET 1 8 7 6 5 NC PFO PFI GND RESET (RESET) WDO 1 2 8 RESET 2 ASM707 MR 3 ASM708 VCC 4
GND 3 ASM708 PFI
ASM705 7 RESET (RESET) ASM706 6 GND 3 (ASM813L) WDI
VCC 2 PFI 4 5 PFO
MR
1
MR 3 (ASM813L) 6 VCC 4 5
ASM705 7 ASM706
WDI PFO PFI GND
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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July 2004
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ASM705 / 706 / 707 / 708 ASM813L
Pin Description
Pin Number ASM705/706 DIP/ SO MicroSO ASM707/708 DIP/ SO MicroSO ASM813L DIP/ SO MicroSO Manual reset input. The active LOW input triggers a reset pulse. A 250 A pull-up current allows the pin to be driven by TTL/CMOS logic or shorted to ground with a switch. +5V power supply input. Ground reference for all signals. Power-fail input voltage monitor. With PFI less than 1.25V, PFO goes LOW. Connect PFI to Ground or VCC when not in use. Power-fail output. The output is active LOW and sinks current when PFI is less than 1.25V. Watchdog input. WDI controls the internal watchdog timer. A HIGH or LOW signal for 1.6sec at WDI allows the internal timer to run-out, setting WDO LOW. The watchdog function is disabled by floating WDI or by connecting WDI to a high impedance three-state buffer. The internal watchdog timer clears when: RESET is asserted; WDI is three-stated ; or WDI sees a rising or falling edge. Not Connected Active LOW reset output. Pulses LOW for 200ms when triggered, and stays LOW whenever VCC is below the reset threshold. RESET remains LOW for 200ms after VCC rises above the reset threshold or MR goes from LOW to HIGH. A watchdog timeout will not trigger RESET unless WDO is connected to MR. Watchdog output. WDO goes LOW when the 1.6 second internal watchdog timer times-out and does not go HIGH until the watchdog is cleared. In addition, when VCC falls below the reset threshold, WDO goes LOW. Unlike RESET, WDO does not have a minimum pulse width and as soon as VCC exceeds the reset threshold, WDO goes HIGH with no delay. Active HIGH reset output. The inverse of RESET. The ASM813L has only a RESET output. Name Function
1
3
1
3
1
3
MR
2 3
4 5
2 3
4 5
2 3
4 5
VCC GND
4
6
4
6
4
6
PFI
5
7
5
7
5
7
PFO
6
8
-
-
6
8
WDI
-
-
6
8
-
-
NC
7
1
7
1
-
-
RESET
8
2
-
-
8
2
WDO
-
-
8
2
7
1
RESET
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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rev 1.2
ASM705 / 706 / 707 / 708 ASM813L
Detailed Description
A proper reset input enables a microprocessor /
VCC
VRT
5V 0V 5V
RESET
microcontroller to start in a known state. ASM70X and ASM813L assert reset to prevent code execution errors during power-up, power-down and brown-out conditions. RESET/RESET Timing The RESET/RESET signals are designed to start a P/C in a known state or return the system to a known state. The ASM707/708 have two reset outputs, one active-HIGH RESET and one active-LOW RESET output. The ASM813L has only an active-HIGH output. RESET is simply the complement of RESET.
tRS
tRS
0V
5V
MR
0V 5V
WDO
MR externally set low
tMD tMR
0V
Figure 1: WDI Three-state operation RESET is guaranteed to be LOW with VCC above 1.2V. During a power-up sequence, RESET remains low until the supply rises above the threshold level, either 4.65V or 4.40V. RESET goes high approximately 200ms after crossing the threshold. During power-down, RESET goes LOW as VCC falls below the threshold level and is guaranteed to be under 0.4V with VCC above 1.2V. In a brownout situation where VCC falls below the threshold level, RESET pulses low. If a brownout occurs during an already initiated reset, the pulse will continue for a minimum of 140ms. Power Failure Detection With Auxiliary Comparator All devices have an auxiliary comparator with 1.25V trip point and uncommitted output (PFO) and noninverting input (PFI). This comparator can be used as a supply voltage monitor with an external resistor voltage divider. The attenuated voltage at PFI should be set just below the 1.25 threshold. As the supply level falls, PFI is reduced causing the PFO output to transit LOW. Normally PFO interrupts the processor so the system can be shut down in a controlled manner. If WDI is floated or connected to a three-stated circuit, the watchdog function is disabled, meaning, it is cleared and not counting. The watchdog timer is also disabled if RESET is asserted. When RESET becomes inactive and the WDI input sees a high or low transition as short as 50ns, the watchdog timer will begin a 1.6 second countdown. Additional Watchdog Timer The watchdog timer available on the ASM705/706/813L monitors P/C activity. An output line on the processor is used to toggle the WDI line. If this line is not toggled within 1.6 seconds, the internal timer puts the watchdog output, WDO, into a LOW state. WDO will remain LOW until a toggle is detected at WDI. Manual Reset (MR) The active-LOW manual reset input is pulled high by a 250A pull-up current and can be driven low by CMOS/TTL logic or a mechanical switch to ground. An external debounce circuit is unnecessary since the 140ms minimum reset time will debounce mechanical pushbutton switches. By connecting the watchdog output (WDO) and MR, a watchdog timeout forces RESET to be generated. The ASM813L should be used when an active-HIGH RESET is required.
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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rev 1.2
transitions at WDI will reset the watchdog timer and initiate a new countdown sequence. WDO will also become LOW and remain so, whenever the supply voltage, VCC , falls below the device threshold level. WDO goes HIGH as soon as VCC transitions above the threshold. There is no minimum pulse width for WDO as there is for the RESET outputs. If WDI is floated, WDO essentially acts as a low-power output indicator.
Supply Voltage
ASM705 / 706 / 707 / 708 ASM813L
BUF
Buffered RESET
VCC
ASM70x
4.7k RESET GND
C or P RESET Input GND
WDI
Bi-directional I/O Pin
Figure 3: Bi-directional Reset Pin Interfacing WDO Monitoring Voltages Other Than VCC The ASM705-708 can monitor voltages other than VCC using the Power Fail circuitry. If a resistive divider is connected RESET from the voltage to be monitored to the Power Fail input (PFI), the PFO will go LOW if the voltage at PFI goes below 1.25V reference. Should hysteresis be desired, connect a resistor (equal to approximately 10 times the sum of the two RESET resistors in the divider) between the PFI and PFO pins. A capacitor between PFI and GND will reduce circuit sensitivity to input high-frequency noise. If it is desired to assert a Figure 2: Watchdog Timing RESET for voltages other than VCC then the PFO output is to be connected to the MR.
Application Information
VIN
Ensuring That RESET is Valid Down to VCC = 0V When VCC falls below 1.1V, the ASM705-708 RESET output no longer pulls down; it becomes indeterminate. To avoid the possibility that stray charges build up and force RESET to the wrong state, a pull-down resistor should be connected to the RESET pin, thus draining such charges to ground and holding RESET low. The resistor value is not critical. A 100k resistor will pull RESET to ground without loading it. Bi-directional Reset Pin Interfacing The ASM705/6/7/8 can interface with P/C bi-directional reset pins by connecting a 4.7k resistor in series with the RESET output and the P/C bi-directional RESET pin.
R2 R1
+5V VCC MR
ASM70X PFO PFI To P
GND
RESET
Figure 4: Monitoring +5V and an additional supply VIN 5 of 15
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
July 2004
rev 1.2
Monitoring a Negative Voltage The Power-Fail circuitry can also monitor a negative supply rail. When the negative rail is OK, PFO will be LOW, and when the negative rail is failing (not negative enough), PFO goes HIGH (the opposite of when positive voltages are monitored). To trigger a reset, these outputs need to be inverted: adding the resistors and transistor as shown achieves this. The RESET output will then have the same sense as for positive voltages: good = HIGH, bad = LOW. It should be noted that this circuit's accuracy depends on the VCC line, the PFI threshold tolerance, and the resistors.
R1 VCC +
ASM705 / 706 / 707 / 708 ASM813L
R3 VCC MR R4 ASM70X PFO PFI
2N3904
R2 GND Negative Input Voltage RESET To P
VCC - 1.25 R1
=
1.25 - VTRIP R2
Figure 5: Monitoring a negative voltage
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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ASM705 / 706 / 707 / 708 ASM813L
Absolute Maximum Ratings
Parameter Pin Terminal Voltage with Respect to Ground VCC All other inputs 1 Input Current at VCC and GND Output Current: All outputs Rate of Rise at VCC Plastic DIP Power Dissipation (Derate 9mW/C above 70C) SO Power Dissipation (Derate 5.9mW/C above 70C) MicroSO Power Dissipation (Derate 4.1mW/C above 70C) Operating Temperature Range ASM705E/706E/707E/708E/813LE ASM706C/707C/708C/813LC Storage Temperature Range Lead Temperature (Soldering 10sec) -40 0 -65 +85 70 160 300 C C C C -0.3 -0.3 6.0 VCC + 0.3 20 20 100 700 470 330 V V mA mA V/s mV mW` mW Min Max Unit
Note: 1. The input voltage limits of PFI and MR can be exceeded if the input current is less than 10mA. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability.
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
7 of 15
July 2004
rev 1.2
ASM705 / 706 / 707 / 708 ASM813L
Electrical Characteristics
Unless otherwise noted, specifications are over the operating temperature range and VCC supply voltages are 2.7V to 5.5V (ASM706P, ASM708R), 3.0 V to 5.5V (ASM706/708S), 3.15V to 5.5V (ASM706/708T) and 4.1V to 5.5.V (ASM706/708J)
Parameter
Symbol ASM705/6/7/8C
Conditions
Min 1.2 1.1 1.2
Typ
Max
Unit
5.5 5.5 5.5
75 75 50 50
Operating Voltage Range
VCC
ASM813L ASM705/6/7/8E, ASM813E ASM705/706C/813LC
V
140 140 140 140 4.75 4.50 V mV 280 ms s 0.25 s V A A
Supply Current
ASM705E/706E/813LE ICC ASM707C/708C ASM707E/708E ASM705/707/813L, Note 1 4.50 4.25
4.65 4.40 40
RESET Threshold RESET Threshold Hysteresis RESET Pulse Width MR Pulse Width MR to RESET Out Delay MR Input Threshold
VRT ASM706/708 Note 1 Note 1 tRS tMR tMD VIH VIL Note 1 2.0 Note 1 140 0.15
200
0.8
MR = 0V ISOURCE = 800A 100 VCC - 1.5 250
MR Pullup current
600
RESET Output Voltage
ISINK = 3.2mA ASM705/5/7/8, VCC = 1.2V, ISINK = 100A ASM707/8/813L, ISOURCE = 800A ASM707/8, ISINK = 1.2mA VCC-1.5
0.4 0.3
V
0.4 0.4
0.9
RESET Output Voltage ASM813L, ISINK =3.2mA ASM813L, VCC = 1.2V, ISOURCE = 4A
V
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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ASM705 / 706 / 707 / 708 ASM813L
Parameter Watchdog Timeout Period WDI Pulse Width
Symbol tWD tWP VIH ASM705/6/813L
Conditions
Min 1.00 50 3.5
Typ 1.60
Max
Unit
2.25
s ns V
VIL = 0.4V, VIH=0.8VCC, ASM705/706/813L, VCC = 5V
WDI Input Threshold VIL
0.8
50 -150 VCC - 1.5 -50
ASM705/6/813L, WDI = VCC WDI Input Current ASM705/6/813L, WDI = 0V VOH WDO Output Voltage VOL PFI Input Threshold PFI Input Current VOH PFO Output Voltage VOL ISINK = 3.2mA ISOURCE = 800A ASM705/6/813L, ISINK = 1.2mA VCC = 5V 1.2 -25 VCC - 1.5 ASM705/6/813L, ISOURCE = 800A
150
A
0.4
1.25 0.01
V V nA V
1.3 25
0.4
Notes 1: RESET (ASM705/6/7/8), RESET(ASM707/8, ASM813L)
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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July 2004
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ASM705 / 706 / 707 / 708 ASM813L
Package Dimensions 8-Pin MicroSO
D
E1
E
A2 A C
0.10mm 0.004in
a L
e
b
A1
Inches Min A A1 A2 b C D e E E1 L a 0.0020 0.0295 0.0098 0.0051 0.1142 Max 0.0433 0.0059 0.0374 0.0157 0.0091 0.1220
Millimeteres Min 0.050 0.75 0.25 0.13 2.90 0.65 BSC 4.90 BSC 2.90 0.40 0 3.10 0.70 6 Max 0.10 0.15 0.95 0.40 0.23 3.10
0.0256 BSC 0.193 BSC 0.1142 0.0157 0 0.1220 0.0276 6
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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July 2004
rev 1.2
ASM705 / 706 / 707 / 708 ASM813L
Package Dimensions (contd) Plastic DIP (8-Pin)
D1
E D A1 E1
A L
0 -15
b2 b
e
eC eA eB
Inches Min A A1 A2 b b2 b3 D D1 E E1 e eA eB eC L 0.015 0.115 0.014 0.045 0.030 0.355 0.005 0.300 0.240 0.100 0.300 0.115 Max 0.210 0.195 0.022 0.070 0.045 0.400 0.325 0.280 0.430 0.060 0.150
Millimeteres Min 0.38 2.92 0.36 1.14 0.80 9.02 0.13 7.62 6.10 2.54 7.62 10.92 Max 5.33 4.95 0.56 1.78 1.14 10.16 8.26 7.11
2.92
3.81 11 of 15
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
July 2004
rev 1.2
ASM705 / 706 / 707 / 708 ASM813L
Package Dimensions (contd) SO (8-Pin)
Inches Min A A1 B C e E H L D 0.150 0.228 0.016 0.189 0.053 0.004 0.013 0.007 0.050 0.157 0.244 0.050 0.197 Max 0.069 0.010 0.020 0.010
Millimeteres Min 1.35 0.10 0.33 0.19 1.27 3.80 5.80 0.40 4.80 4.00 6.20 1.27 2.00 Max 1.75 0.25 0.51 0.25
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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ASM705 / 706 / 707 / 708 ASM813L
Ordering Codes
Part Number Reset Threshold (V) Temperature Range Pins-Package
ASM705 Active LOW Reset, Watchdog Output And Manual RESET ASM705CPA ASM705CSA ASM705CUA ASM705EPA ASM705ESA ASM705EUA 4.65 4.65 4.65 4.65 4.65 4.65 0C to +70 C 0C to +70 C 0C to +70 C -40C to +85C -40C to +85C -40C to +85C 8-Plastic DIP 8-SO 8-MicroSO 8-Plastic DIP 8-SO 8-MicroSO
ASM706 Active LOW Reset, Watchdog Output And Manual RESET ASM706CPA ASM706CSA ASM706CUA ASM706EPA ASM706ESA 4.40 4.40 4.40 4.40 4.40 0C to +70 C 0C to +70 C 0C to +70 C -40C to +85C -40C to +85C 8-Plastic DIP 8-SO 8-MicroSO 8-Plastic DIP 8-SO
ASM707 Active LOW & HIGH Reset with Manual RESET ASM707CPA ASM707CSA ASM707CUA ASM707EPA ASM707ESA 4.65 4.65 4.65 4.65 4.65 0C to +70 C 0C to +70 C 0C to +70 C -40C to +85C -40C to +85C 8-Plastic DIP 8-SO 8-MicroSO 8-Plastic DIP 8-SO
ASM708Active LOW & HIGH Reset with Manual RESET ASM708CPA ASM708CSA ASM708CUA ASM708EPA ASM708ESA 4.40 4.40 4.40 4.40 4.40 0C to +70 C 0C to +70 C 0C to +70 C -40C to +85C -40C to +85C 8-Plastic DIP 8-SO 8-MicroSO 8-Plastic DIP 8-SO
ASM813L Active HIGH Reset, Watchdog Output And Manual RESET ASM813LCPA ASM813LCSA ASM813LCUA ASM813LEPA ASM813LESA 4.65 4.65 4.65 4.65 4.65 0C to +70 C 0C to +70 C 0C to +70 C -40C to +85C -40C to +85C 8-Plastic DIP 8-SO 8-MicroSO 8-Plastic DIP 8-SO
Low Power P Supervisor Circuits
Notice: The information in this document is subject to change without notice
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ASM705 / 706 / 707 / 708 ASM813L
Feature Summary
ASM705 Power fail detector Brownout detection Manual RESET input Power-up/down RESET Watchdog Timer Active HIGH RESET output Active LOW RESET output RESET Threshold (V) 4.65 4.40 4.65 4.40 4.65 ASM706 ASM707 ASM708 ASM813L
Low Power P Supervisor Circuits
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ASM705 / 706 / 707 / 708 ASM813L
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:ASM705 / 706 / 707 / 708 ASM813L Document Version: 1.2
(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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