多功能微处理器监控电路SGM706数据手册.pdf

SGM706 Low-Cost,Microprocessor Supervisory Circuit GENERAL DESCRIPTION The SGM706 microprocessor supervisory circuit reduces the complexity and number of components required to monitor power-supply and monitor microprocessor activity.It significantly improves system reliability and accuracy compared to separate ICs or discrete components.The SGM706 provides power-supply monitoring circuitry that generates a reset output during power-up,power-down and brownout conditions.The reset output remains operational with VCC as low as 1V.Independent watchdog monitoring circuitry is also provided.This is activated if the watchdog input has not been toggled within 1.6 seconds.In addition,there is a 1.25V threshold detector for power-fail warning,low-battery detection,or monitoring an additional power supply.An active-low manual-reset input(MR)is also included.The SGM706 is available in Green SOIC-8 package.It operates over an ambient temperature range of-40 to+85.FEATURES?Precision Supply-Voltage Monitor 4.65V for SGM706-L 4.40V for SGM706-M 4.0V for SGM706-J 3.08V for SGM706-T 2.93V for SGM706-S 2.63V for SGM706-R?Guaranteed RESET Valid at VCC=1V?200ms Reset Pulse Width?Debounced TTL/CMOS-Compatible Manual-Reset Input?Independent Watchdog Timer(1.6sec)Timeout?Voltage Monitor for Power-Fail or Low-Battery Warning?-40 to+85 Operating Temperature Range?Green SOIC-8 Package APPLICATIONS Computers Controllers Intelligent Instruments Automotive Systems Critical P Power Monitoring REV.A.1SG Micro Limited www.sg-Low-Cost,Microprocessor SGM706 Supervisory Circuit 2SG Micro Limited www.sg- PACKAGE/ORDERING INFORMATION MODEL RESET THRESHOLD(V)PACKAGE DESCRIPTIONORDERING NUMBER PACKAGE MARKING PACKAGE OPTION 4.65 SOIC-8 SGM706-LYS8G/TR SGM706-LYS8 Tape and Reel,25004.40 SOIC-8 SGM706-MYS8G/TRSGM706-MYS8 Tape and Reel,25004.0 SOIC-8 SGM706-JYS8G/TR SGM706-JYS8 Tape and Reel,25003.08 SOIC-8 SGM706-TYS8G/TR SGM706-TYS8 Tape and Reel,25002.93 SOIC-8 SGM706-SYS8G/TRSGM706-SYS8 Tape and Reel,2500SGM706 2.63 SOIC-8 SGM706-RYS8G/TRSGM706-RYS8 Tape and Reel,2500 NOTE:Order number is defined as the follow:ORDER NUMBER SGM 706-X Y X G/TRPackage TypeTape and ReelS8 SOIC-8Operating Temperature RangeY -40 to+85RESET THRESHOLDL:4.65VM:4.40V J:4.0VT:3.08V S:2.93VR:2.63V Green product CAUTION This integrated circuit can be damaged by ESD if you dont pay attention to ESD protection.SGMICRO recommends that all integrated circuits be handled with appropriate precautions.Failure to observe proper handling and installation procedures can cause damage.ESD damage can range from subtle performance degradation to complete device failure.Precision integrated circuits may be more susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.SGMICRO reserves the right to make any change in circuit design,specification or other related things if necessary without notice at any time.Please contact SGMICRO sales office to get the last datasheet.ABSOLUTE MAXIMUM RATINGS(Typical values are at TA=+25,unless otherwise noted.)Terminal Voltage(with respect to GND)VCC.-0.3V to 6.0V All Other Inputs.-0.3V to(VCC+0.3V)Input Current,VCC.20mA GND.20mA Output Current,(all outputs).20mA Operating Temperature Range.-40 to+85 Junction Temperature.150 Storage Temperature.-65 to+150 Lead Temperature(soldering,10sec).260 ESD Susceptibility HBM.4000V MM.300V NOTE:Stresses beyond those listed under“Absolute Maximum Ratings”may cause permanent damage to the device.These are stress ratings only,and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied.Exposure to absolute Maximum rating conditions for extended periods may affect device reliability.Low-Cost,Microprocessor SGM706 Supervisory Circuit 3SG Micro Limited www.sg-TYPICAL OPERATION CIRCUIT VCCMRPFIWDOPFOWDIVCCUNREGULATED DC+5V DC LINEARREGULATORSGM706MICROPROCESSORPUSHBUTTONSWITCHI/O LINENMIINTERRUPTRESETRESETLow-Cost,Microprocessor SGM706 Supervisory Circuit 4SG Micro Limited www.sg-PIN CONFIGURATION(TOP VIEW)SGM706SOIC-8VCC12345678MRGNDPFIWDIWDOPFORESET PIN DESCRIPTION PIN NAME FUNCTION 1 MR Manual-Reset Input triggers a reset pulse when pulled below 0.8V.This active-low input has an internal 250A(VCC=+5V)pull-up current.It can be driven from a TTL or CMOS logic line as well as shorted to ground with a switch.2 VCC Power Supply Voltage that is monitored.3 GND 0V Ground Reference for all signals.4 PFI Power-Fail Voltage Monitor Input.When PFI is less than 1.25V,PFO goes low.Connect PFI to GND or VCC when not used.5 PFO Power-Fail Output goes low and sinks current when PFI is less than 1.25V;otherwise PFO stays high.6 WDI Watchdog Input.If WDI remains high or low for 1.6sec,the internal watchdog timer runs out and WDO goes low(BLOCK DIAGRAM).Floating WDI or connecting WDI to a high-impedance three-state buffer disables the watchdog feature.The internal watchdog timer clears whenever reset is asserted,WDI is three-stated,or WDI sees a rising or falling edge.7 RESET Active-Low Reset Output pulses low for 200ms when triggered,and stays low whenever VCC is below the reset threshold(4.65V for SGM706-L,4.4V for SGM706-M,4.0V for SGM706-J,3.08V for SGM706-T and 2.93V for SGM706-S,2.63V for SGM706-R).It 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.8 WDO Watchdog Output pulls low when the internal watchdog timer finishes its 1.6sec count and does not go high again until the watchdog is cleared.WDO also goes low during low-line conditions.Whenever VCC is below the reset threshold,WDO stays low;however,unlike RESET,WDO does not have a minimum pulse width.As soon as VCC rises above the reset threshold,WDO goes high with no delay.Low-Cost,Microprocessor SGM706 Supervisory Circuit 5SG Micro Limited www.sg- ELECTRICAL CHARACTERISTICS(VCC=4.75V to 5.5V for SGM706-L;VCC=4.5V to 5.5V for SGM706-M;VCC=4.07V to 5.5V for SGM706-J;VCC=3.14V to 5.5V for SGM706-T;VCC=2.95V to 5.5V for SGM706-S;VCC=2.68V to 5.5V for SGM706-R;TA=-40C to+85C,unless otherwise noted.)PARAMETER CONDITIONS MIN TYP MAX UNITSOperating Voltage Range(VCC)1.0 5.5 V Supply Current(ISUPPLY)50 150 A SGM706-L 4.5 4.65 4.75 SGM706-M 4.25 4.4 4.5 SGM706-J 3.91 4.0 4.07 SGM706-T 3.02 3.08 3.14 SGM706-S 2.85 2.93 2.95 Reset Threshold(VRT)SGM706-R 2.56 2.63 2.68 V SGM706-L,SGM706-M 40 SGM706-J 34 SGM706-T,SGM706-S 25 Reset Threshold Hysteresis SGM706-R 22 mV Reset Pulse Width(tRS)120 200 280 ms ISOURCE=800A VCC-1.5 Isink=3.2mA 0.4 RESET Output Voltage VCC=1V,Isink=50A 0.3 V Watchdog Timeout Period(tWD)1.0 1.6 2.25 sec WDI Pulse Width(tWP)VIL=0.4V,VIH=VCC 70 ns Low VCC=5V 0.8 High VCC=5V 3.5 Low VRST(MAX)VCC 3.6V 0.8 WDI Input Threshold High VRST(MAX)VCC 3.6V 0.7 VCC V WDI=VCC 50 150 WDI Input Current WDI=0V-150-50 A ISOURCE=800A VCC-1.5 WDOOutput Voltage Isink=1.2mA 0.4 V MR Pull-Up Current MR=0V 100 600 A MR Pulse Width(tMR)250 ns Low 0.8 MR Input Threshold High TA=+25 2 V MR to Reset Out Delay(tMD)350 ns PFI Input Threshold VCC=5V 1.18 1.25 1.3 V PFI Input Current 0.2 nA ISOURCE=800A VCC-1.5 PFOOutput Voltage Isink=3.2mA 0.4 V Low-Cost,Microprocessor SGM706 Supervisory Circuit 6SG Micro Limited www.sg- BLOCK DIAGRAM WATCHDOGTRANSITIONDETECTORWATCHDOGTIMER+_+_TIMEBASE FORRESET ANDWATCHDOGRESETGENERATORSGM706VCC250A4.65V for SGM706-L*1.25V87561243GNDPFIVCCWDI*4.65V for SGM706-L 4.40V for SGM706-M 4.0V for SGM706-J 3.08V for SGM706-T 2.93V for SGM706-S 2.63V for SGM706-RMRPFORESETWDO Low-Cost,Microprocessor SGM706 Supervisory Circuit 7SG Micro Limited www.sg- TYPICAL PERFORMANCE CHARACTERISTICS VCCVCC2k330pFGNDRESETRESET+-PFI+5VPFO+1.25V30pF1k+-PFI+5V+1.25V30pFPFO1kVCCVCC10k30pFGNDRESETRESETLow-Cost,Microprocessor SGM706 Supervisory Circuit 8SG Micro Limited www.sg- TYPICAL PERFORMANCE CHARACTERISTICS Low-Cost,Microprocessor SGM706 Supervisory Circuit 9SG Micro Limited www.sg- APPLICATION NOTES Ensuring a Valid RESET Output Down to VCC=0V When VCC falls below 1V,the SGM706 RESET output no longer sinks currentit becomes an open circuit.High-impedance CMOS logic inputs can drift to undetermined voltages if left undriven.If a pull-down resistor is added to the RESET pin as shown in Figure 1,any stray charge or leakage currents will be drained to ground,holding RESET low.Resistor value(R1)is not critical.It should be about 100k,large enough not to load RESET and small enough to pull RESET to ground.R1SGM706RESET Figure 1.RESET Valid to Ground Circuit Monitoring Voltages Other Than the Unregulated DC Input Monitor voltages other than the unregulated DC by connecting a voltage divider to PFI and adjusting the ratio appropriately.If required,add hysteresis by connecting a resistor(with a value approximately 10 times the sum of the two resistors in the potential divider network)between PFI and PFO.A capacitor between PFI and GND will reduce the power-fail circuits sensitivity to high-frequency noise on the line being monitored.RESET can be asserted on other voltages in addition to the+5V VCC line.Connect PFO to MR to initiate a RESET pulse when PFI drops below 1.25V.Figure 2 shows the SGM706 configured to assert RESETwhen the+5V supply falls below the reset threshold,or when the+12V supply falls below approximately 11V.VCCMRPFOPFIRESET+12V+5V1M1%130k1%TO PGNDSGM706 Figure 2.Monitoring Both+5V and+12V Monitoring a Negative Voltage The power-fail comparator can also monitor a negative supply rail(Figure 3).When the negative rail is good(a negative voltage of large magnitude),PFO is low,and when the negative rail is degraded(a negative voltage of lesser magnitude),PFO is high.By adding the resistors and transistor as shown,a high PFO triggers reset.As long as PFO remains high,the SGM706 will keep reset asserted(RESET=low,RESET=high).Note that this circuits accuracy depends on the PFI threshold tolerance,the VCC line,and the resistors.VCCMRPFOPFI+5VGNDSGM706R1R2V-100k100kTO P+5V0V+5V0VV-VTRIP0VMRPFO5 1.25R11.25-VTRIPR2VTRIP 0=2N3904RESET Figure 3.Monitoring a Negative Voltage Interfacing to Ps with Bidirectional Reset Pins Ps with bidirectional reset pins,such as the Motorola 68HC11 series,can contend with the SGM706 RESET output.If,for example,the RESET output is driven high and the Microprocessor wants to pull it low,indeterminate logic levels may result.To correct this,connect a 4.7k resistor between the RESET output and the P reset I/O,as in Figure 4.Buffer the RESET output to other system components.VCCRESETMicroprocessorGNDSGM706VCCRESETGND4.7kBUFFRED RESET TO OTHER SYSTEM COMPONENTS Figure 4.Interfacing to Microprocessors with Bidirectional Reset I/OLow-Cost,Microprocessor SGM706 Supervisory Circuit 10SG Micro Limited www.sg- PACKAGE OUTLINE DIMENSIONS SOIC-8 DEE1ebDAA2A1cL Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 1.350 1.750 0.053 0.069 A1 0.100 0.250 0.004 0.010 A2 1.350 1.550 0.053 0.061 b 0.330 0.510 0.013 0.020 c 0.170 0.250 0.006 0.010 D 4.700 5.100 0.185 0.200 E 3.800 4.000 0.150 0.157 E1 5.800 6.200 0.228 0.244 e 1.270 BSC 0.050 BSC L 0.400 1.270 0.016 0.050 0 8 0 8