ADM709TARZ资料

a

FEATURESPrecision Supply Voltage Monitor+5 V, +3.3 V, +3 V Power Supply Monitor35 ␮A Quiescent Current140 ms (min) Power-On Reset PulseLow Cost8-Pin DIP/SO PackagesUpgrade for MAX709APPLICATIONSMicroprocessor SystemsComputersControllersIntelligent InstrumentsCritical ␮P MonitoringAutomotive SystemsCritical ␮P Power MonitoringGENERAL DESCRIPTIONThe ADM709 contains a power supply monitor which generatesa system reset during power-up, power-down and brownoutconditions. When VCC falls below the reset threshold, RESETgoes low and holds the µP in reset. On power-up the RESEToutput is held low for 140 ms after VCC rises above the thresh-old. The RESET output remains operational with VCC as lowas 1 V.Three supply-voltage threshold levels are available suitable for+5 V, +3.3 V and for +3 V supply monitoring. The actual resetvoltage threshold is given below.The ADM709 is available in 8-pin DIP and SOIC packages.Table I.Reset ThresholdSuffixVoltage (V)L4.65M4.40T3.08S2.93R2.63REV.0

Information furnished by Analog Devices is believed to be accurate andreliable. However, no responsibility is assumed by Analog Devices for itsuse, nor for any infringements of patents or other rights of third partieswhich may result from its use. No license is granted by implication orotherwise under any patent or patent rights of Analog Devices.

Power Supply Monitorwith ResetADM709FUNCTIONAL BLOCK DIAGRAMADM709VCCRESETVGENERATORRESETTHGNDVCCVCCADM709µPRESETRESETGNDGNDTypical Operating CircuitORDERING GUIDEResetTemperaturePackageModelThresholdRangeOption*ADM709LAN4.65 V–40°C to +85°CN-8ADM709LAR4.65 V–40°C to +85°CSO-8ADM709MAN4.40 V–40°C to +85°CN-8ADM709MAR4.40 V–40°C to +85°CSO-8ADM709TAN3.08 V–40°C to +85°CN-8ADM709TAR3.08 V–40°C to +85°CSO-8ADM709SAN2.93 V–40°C to +85°CN-8ADM709SAR2.93 V–40°C to +85°CSO-8ADM709RAN2.63 V–40°C to +85°CN-8ADM709RAR2.63 V–40°C to +85°CSO-8*N = Plastic DIP; SO = SOIC.© Analog Devices, Inc., 1995

One Technology Way, P.O. Box 9106, Norwood. MA 02062-9106, U.S.A.Tel: 617/329-4700Fax: 617/326-8703

元器件交易网www.cecb2b.com

ADM709–SPECIFICATIONS(V = Full Operating Range, T = TCCAMIN to TMAX unless otherwise noted)ParameterVCC Operating Voltage RangeSupply CurrentMin1.01.2TypMax5.55.5851101502004.7.503.153.002.70UnitsVVµAµAµAµAVVVVVµsTest Conditions/CommentsTA = 0°C to +70°CTA = –40°C to +85°CVCC < 3.6 V, TA = 0°C to +70°CVCC < 3.6 V, TA = –40°C to +85°CVCC < 5.5 V, TA = 0°C to +70°CVCC < 5.5 V, TA = –40°C to +85°CADM709LADM709MADM709TADM709SADM709RVCC = Reset Threshold max–minVCC = Reset Threshold max, VCC RisingADM709R/S/T, ISINK = 1.2 mA. VCC = ResetThreshold minADM709L/M, ISINK = 3.2 mA. VCC = ResetThreshold minISINK = 50 µA. VCC ≥ 1.0 VISINK = 100 µA. VCC ≥ 1.2 VADM709R/S/T, ISOURCE = 500 µA, VCC ≥ ResetThreshold maxADM709L/M, ISOURCE = 800 µA, VCC ≥ ResetThreshold max3535656..253.002.852.5.6.403.082.932.6320140280Reset ThresholdVCC to RESET DelayRESET Active Time-Out PeriodRESET Output Voltage3800.30.40.30.4msVVVVVV0.8 × VCCVCC–1.5 VSpecifications subject to change without notice.ABSOLUTE MAXIMUM RATINGS*(TA = +25°C unless otherwise noted)PIN FUNCTION DESCRIPTIONVCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .–0.3 V to +6 VRESET Output . . . . . . . . . . . . . . . . . . .–0.3 V to VCC + 0.3 VVCC Input Current . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 mARESET Output Current . . . . . . . . . . . . . . . . . . . . . . . .20 mAPower Dissipation, N-8 DIP . . . . . . . . . . . . . . . . . . . .727 mWθJA Thermal Impedance . . . . . . . . . . . . . . . . . . . . .135°C/WPower Dissipation, SO-8 SOIC . . . . . . . . . . . . . . . . . .470 mWθJA Thermal Impedance . . . . . . . . . . . . . . . . . . . . .110°C/WOperating Temperature RangeIndustrial ( A Version) . . . . . . . . . . . . . . . . .–40°C to +85°CLead Temperature (Soldering, 10 secs) . . . . . . . . . . . .+300°CVapor Phase (60 secs) . . . . . . . . . . . . . . . . . . . . . . . . .+215°CInfrared (15 secs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+220°CStorage Temperature Range . . . . . . . . . . . . .–65°C to +150°CESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .>5 kV*MnemonicPin No.NCVCCRESET1, 4, 5, 6, 827FunctionNo Connect Pins.+5 V, +3.3 V, +3 V Power SupplyInput.Logic Output. It remains low whileVCC is below the reset thresholdvoltage and for 280 ms (typ) afterVCC rises above the threshold.Ground, 0 V.GND3PIN CONFIGURATIONStresses above those listed under “Absolute Maximum Ratings” may causepermanent damage to the device. This is a stress rating only and functionaloperation of the device at these or any other conditions above those listed in theoperational sections of this specification is not implied. Exposure to absolutemaximum ratings for extended periods of time may affect device reliability.NC1VCC2GND3NC48NCRESETNCNCADM709TOP VIEW(Not to Scale)765NC = NO CONNECT–2–REV. 0

元器件交易网www.cecb2b.com

ADM709

ADM709VCCVTHRESETGENERATORRESETRESET at Voltages < 1 VGNDThe ADM709 RESET output is guaranteed to operate withsupply voltages as low as 1 V. If it is desired that the RESEToutput remains low below 1 V, then a pull-down resistor shouldbe connected between the RESET output and GND. A resistorof 100 kΩ is suitable. This is illustrated in Figure 5.Figure 1.Functional Block DiagramADM709RESETVCCVCCR1GNDADM709RESETGNDRESETµPGNDFigure 5.RESET Valid @ VCC < 1 VGlitch ImmunityFigure 2.Typical Operating CircuitCIRCUIT INFORMATIONRESET OutputThe ADM709 is immune to short transients which may occuron the VCC line. This is important so that spurious resets are notgenerated as a result of minor glitches on the power supply.Additional glitch immunity may be obtained by connecting acapacitor (0.1 µF or greater) as close as possible to the VCC pinon the device.Microprocessors with Bidirectional I-ORESET is an active low output which provides a reset signal tothe microprocessor whenever the VCC supply voltage is belowthe reset threshold. An internal timer holds RESET low for140 ms after the voltage on VCC rises above the threshold. Thisis intended as a power-on reset signal for the processor. It allowstime for the power supply and microprocessor to stabilize afterpower up. Similarly a power supply brownout will initiate a pro-cessor reset. On power-down, the RESET output remains lowwith VCC as low as 1 V. This ensures that the microprocessor isheld in a stable shutdown condition as the power supply drops.VRTVRTSome microprocessors or microcontrollers such as theMC68HC11 have bidirectional reset lines. In order to avoidsignal contention, a resistor of 4.7 kΩ should be connectedbetween the ADM709 RESET output and the microcontrollerRESET line. This arrangement is shown in Figure 6.+5VBUFFEREDRESETVCCVCCADM709 tRSRESETµPRESETRESETGNDGNDFigure 3.Power Off/On RESET TimingFigure 6.Interfacing to Microprocessors withBidirectional RESET

VCCRESET400ms/DIVFigure 4.RESET Output vs. VCCREV. 0–3–

元器件交易网www.cecb2b.com

ADM709

OUTLINE DIMENSIONSDimensions shown in inches and (mm).8-Lead Plastic DIP(N-8)850.280 (7.11)PIN 10.240 (6.10)140.430 (10.92)0.325 (8.25)0.348 (8.84)0.300 (7.62)0.2100.060 (1.52)0.195 (4.95)(5.33)0.015 (0.38)0.115 (2.93)MAX0.1300.160 (4.06)(3.30)0.015 (0.381)0.115 (2.93)MIN0.008 (0.204)0.022 (0.558)0.1000.070 (1.77)SEATING0.014 (0.356)(2.)0.045 (1.15)PLANEBSC8-Lead SOIC(SO-8)850.1574 (4.00)PIN 10.1497 (3.80)140.2440 (6.20)0.2284 (5.80)0.1968 (5.00) 0.0196 (0.50)0.10 (4.80)0.0099 (0.25)x 45°0.0098 (0.25)0.0688 (1.75)0.0040 (0.10)0.0532 (1.35)8°0.05000.0192 (0.49)(1.27)0.0098 (0.25)0°0.0500 (1.27)BSC0.0138 (0.35)0.0075 (0.19)0.0160 (0.41)–4–59/4–81–2202C.A.S.U NI DETNIRPREV. 0