ASM705/706/707/708 and ASM813L Low Power P Supervisor Circuits General Description Features The ASM705 / 706 / 707 / 708 and ASM813L are cost effective CMOS supervisor circuits that monitor powersupply and battery voltage level, and P/C operation. Precision power supply monitor 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. Debounced manual reset input All devices are available in 8-pin DIP, SO and MicroSO packages. 4.65V threshold (ASM705/707/813L) 4.40V threshold (ASM706/708) 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 Application Computers and embedded controllers Portable/Battery-operated systems Intelligent instruments Wireless communication systems PDAs and hend-held equipment Automative Systems Safety Systems Typical Operating Circuit (c)2010 SCILLC. All rights reserved. JANUARY 2010 - Rev. 2 Publication Order Number: ASM705/D ASM705/706/707/708 and ASM813L Block Diagram Pin Configuration Rev. 2 | Page 2 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L Pin Description Pin Number ASM705/706 DIP/ SO MicroSO ASM707/708 DIP/ SO MicroSO ASM813L DIP/ SO Name Function MicroSO 1 3 1 3 1 3 MR 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. 2 4 2 4 2 4 VCC +5V power supply input. 3 5 3 5 3 5 GND Ground reference for all signals. 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 - - 8 2 - - 8 2 WDO - - 8 2 7 1 RESET RESET Rev. 2 | Page 3 of 14 | www.onsemi.com 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 threestate 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 only has a RESET output. ASM705/706/707/708 and ASM813L Detailed Description A proper reset input enables a microprocessor / 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 activeHIGH RESET and one active-LOW RESET output. The ASM813L has only an active-HIGH output. RESET is simply the complement of RESET. 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 brown-out occurs during an already initiated reset, the pulse will continue for a minimum of 140ms. 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. Power Failure Detection With Auxiliary Comparator All devices have an auxiliary comparator with 1.25V trip Watchdog Timer point and uncommitted output (PFO) and noninverting 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. 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 transitions at WDI will reset the watchdog timer and initiate a new countdown sequence. Rev. 2 | Page 4 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L 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. Monitoring Voltages Other Than VCC Application Information 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. The ASM705-708 can monitor voltages other than VCC using the Power Fail circuitry. If a resistive divider is connected 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 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 RESET for voltages other than VCC then the PFO output is to be connected to the MR. 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. Rev. 2 | Page 5 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L 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. Rev. 2 | Page 6 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L Absolute Maximum Ratings 1 Parameter Min Max Unit -0.3 6.0 V -0.3 VCC + 0.3 V 20 mA Output Current: All outputs 20 mA Rate of Rise at VCC 100 V/s Plastic DIP Power Dissipation (Derate 9mW/C above 70C) 700 mV 470 mW 330 mW Pin Terminal Voltage with Respect to Ground VCC All other inputs 2 Input Current at VCC and GND 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 -40 +85 C ASM705C/706C/707C/708C/813LC 0 70 C -65 160 C 300 C 2 200 KV V Storage Temperature Range Lead Temperature (Soldering 10sec) ESD rating HBM MM Note: 1. These are stress ratings only and functional operation is not implied. Exposure to absolute maximum ratings for prolonged time periods may affect device reliability. 2. The input voltage limits of PFI and MR can be exceeded if the input current is less than 10mA. Rev. 2 | Page 7 of 14 | www.onsemi.com ASM705/706/707/708 and 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 Operating Voltage Range SYMBOL VCC Supply Current ICC RESET Threshold VRT RESET Threshold Hysteresis RESET Pulse Width MR Pulse Width MR to RESET Out Delay MR Input Threshold MR Pullup current tRS tMD VIH VIL WDO Output Voltage 4.50 4.25 140 280 100 VCC - 1.5 ISOURCE = 800A ISINK = 3.2mA Note: 1. RESET (ASM705/6/7/8), RESET(ASM707/8, ASM813L) Rev. 2 | Page 8 of 14 | www.onsemi.com V ms 250 0.8 600 s V A 0.4 0.3 V 0.4 0.4 V 2.25 S 0.9 50 3.5 ASM705/6/813L, WDI = VCC ASM705/6/813L, WDI = 0V ASM705/6/813L, ISOURCE = 800A ASM705/6/813L, ISINK = 1.2mA VCC = 5V A VCC - 1.5 VIL = 0.4V, VIH=0.8VCC, ASM705/706/813L, VCC = 5V V s 0.25 tWP VIH VIL VOH VOL 200 Unit mV 2.0 1.00 PFI Input Threshold PFI Input Current 75 75 50 50 4.65 4.40 5.5 5.5 5.5 140 140 140 140 4.75 4.50 0.15 ASM705/6/813L VOH Max 1 tWD VOL PFO Output Voltage 1 MR = 0V ISOURCE = 800A ISINK = 3.2mA ASM705/6/7/8, VCC = 1.2V, ISINK = 100A ASM707/8/813L, ISOURCE = 800A ASM707/8, ISINK = 1.2mA ASM813L, ISINK =3.2mA ASM813L, VCC = 1.2V, ISOURCE = 4A WDI Input Current TYP 1.2 1.1 1.2 40 tMR RESET Output Voltage WDI Input Threshold Min 1 RESET Output Voltage Watchdog Timeout Period WDI Pulse Width Test Conditions ASM705/6/7/8C ASM813L ASM705/6/7/8E, ASM813E ASM705/706C/813LC ASM705E/706E/813LE ASM707C/708C ASM707E/708E 1 ASM705/707/813L 1 ASM706/708 -150 1.60 ns 50 -50 0.8 150 V A VCC - 1.5 V 0.4 1.2 -25 VCC - 1.5 1.25 0.01 1.3 25 0.4 V nA V ASM705/706/707/708 and ASM813L Package Dimensions 8-Pin MicroSO Rev. 2 | Page 9 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L Package Dimensions (contd) Plastic DIP (8-Pin) Rev. 2 | Page 10 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L Package Dimensions (contd) SO (8-Pin) Rev. 2 | Page 11 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L Ordering Codes Part Number TIN - LEAD DEVICES Reset Threshold Temperature Pins-Package Package Marking ASM705 Active LOW Reset, Watchdog Output And Manual RESET ASM705CPA 4.65 0C to +70 C 8-Plastic DIP ASM705CPA ASM705CSA 4.65 0C to +70 C 8-SO ASM705CSA ASM705CUA 4.65 0C to +70 C 8-MicroSO ASM705CUA ASM705EPA 4.65 -40C to +85C 8-Plastic DIP ASM705EPA ASM705ESA 4.65 -40C to +85C 8-SO ASM705ESA ASM705EUA 4.65 -40C to +85C 8-MicroSO ASM705EUA 8-Plastic DIP ASM706CPA ASM706 Active LOW Reset, Watchdog Output And Manual RESET ASM706CPA 4.40 0C to +70 C ASM706CSA 4.40 0C to +70 C 8-SO ASM706CSA ASM706CUA 4.40 0C to +70 C 8-MicroSO ASM706CUA ASM706EPA 4.40 -40C to +85C 8-Plastic DIP ASM706EPA ASM706ESA 4.40 -40C to +85C 8-SO ASM706ESA ASM707 Active LOW & HIGH Reset with Manual RESET ASM707CPA 4.65 0C to +70 C 8-Plastic DIP ASM707CPA ASM707CSA 4.65 0C to +70 C 8-SO ASM707CSA ASM707CUA 4.65 0C to +70 C 8-MicroSO ASM707CUA ASM707EPA 4.65 -40C to +85C 8-Plastic DIP ASM707EPA ASM707ESA 4.65 -40C to +85C 8-SO ASM707ESA 8-Plastic DIP ASM708CPA ASM708Active LOW & HIGH Reset with Manual RESET ASM708CPA 4.40 0C to +70 C ASM708CSA 4.40 0C to +70 C 8-SO ASM708CSA ASM708CUA 4.40 0C to +70 C 8-MicroSO ASM708CUA ASM708EPA 4.40 -40C to +85C 8-Plastic DIP ASM708EPA ASM708ESA 4.40 -40C to +85C 8-SO ASM708ESA ASM813L Active HIGH Reset, Watchdog Output And Manual RESET ASM813LCPA 4.65 0C to +70 C 8-Plastic DIP ASM813LCPA ASM813LCSA 4.65 0C to +70 C 8-SO ASM813LCSA ASM813LCUA 4.65 0C to +70 C 8-MicroSO ASM813LCUA ASM813LEPA 4.65 -40C to +85C 8-Plastic DIP ASM813LEPA ASM813LESA 4.65 -40C to +85C 8-SO ASM813LESA Note: For parts to be packed in Tape and Reel, add "-T" at the end of the part number. Rev. 2 | Page 12 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L Ordering Codes Part Number LEAD FREE DEVICES Reset Threshold Temperature Pins-Package Package Marking ASM705 Active LOW Reset, Watchdog Output And Manual RESET ASM705CPAF 4.65 0C to +70 C 8-Plastic DIP ASM705CPAF ASM705CSAF 4.65 0C to +70 C 8-SO ASM705CSAF ASM705CUAF 4.65 0C to +70 C 8-MicroSO ASM705CUAF ASM705EPAF 4.65 -40C to +85C 8-Plastic DIP ASM705EPAF ASM705ESAF 4.65 -40C to +85C 8-SO ASM705ESAF ASM705EUAF 4.65 -40C to +85C 8-MicroSO ASM705EUAF 8-Plastic DIP ASM706CPAF ASM706 Active LOW Reset, Watchdog Output And Manual RESET ASM706CPAF 4.40 0C to +70 C ASM706CSAF 4.40 0C to +70 C 8-SO ASM706CSAF ASM706CUAF 4.40 0C to +70 C 8-MicroSO ASM706CUAF ASM706EPAF 4.40 -40C to +85C 8-Plastic DIP ASM706EPAF ASM706ESAF 4.40 -40C to +85C 8-SO ASM706ESAF ASM707 Active LOW & HIGH Reset with Manual RESET ASM707CPAF 4.65 0C to +70 C 8-Plastic DIP ASM707CPAF ASM707CSAF 4.65 0C to +70 C 8-SO ASM707CSAF ASM707CUAF 4.65 0C to +70 C 8-MicroSO ASM707CUAF ASM707EPAF 4.65 -40C to +85C 8-Plastic DIP ASM707EPAF ASM707ESAF 4.65 -40C to +85C 8-SO ASM707ESAF 8-Plastic DIP ASM708CPAF ASM708Active LOW & HIGH Reset with Manual RESET ASM708CPAF 4.40 0C to +70 C ASM708CSAF 4.40 0C to +70 C 8-SO ASM708CSAF ASM708CUAF 4.40 0C to +70 C 8-MicroSO ASM708CUAF ASM708EPAF 4.40 -40C to +85C 8-Plastic DIP ASM708EPAF ASM708ESAF 4.40 -40C to +85C 8-SO ASM708ESAF ASM813L Active HIGH Reset, Watchdog Output And Manual RESET ASM813LCPAF 4.65 0C to +70 C 8-Plastic DIP ASM813LCPAF ASM813LCSAF 4.65 0C to +70 C 8-SO ASM813LCSAF ASM813LCUAF 4.65 0C to +70 C 8-MicroSO ASM813LCUAF ASM813LEPAF 4.65 -40C to +85C 8-Plastic DIP ASM813LEPAF ASM813LESAF 4.65 -40C to +85C 8-SO ASM813LESAF Note: For parts to be packed in Tape and Reel, add "-T" at the end of the part number. Rev. 2 | Page 13 of 14 | www.onsemi.com ASM705/706/707/708 and ASM813L Feature Summary ASM705 ASM706 ASM707 ASM708 ASM813L 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 ON Semiconductor and are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental damages. 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