SUPPLY VOLTAGE MONITOR ISSUE 3 JULY 6 DEVICE DESCRIPTION The ZSM3 is a three terminal under voltage monitor circuit for use in microprocessor systems. The threshold voltage of the device has been set to.63 volts making it ideal for 3 volt circuits. Included in the device is a precise voltage reference and a comparator with built in hysteresis to prevent erratic operation. The ZSM3 features an open collector output capable of sinking at least lma which only requires a single external resistor to interface to following circuits. Operation of the device is guaranteed from one volt upwards, from this level to the device threshold voltage the output is held low providing a power on reset function. Should the supply voltage, once established, at any time drop below the threshold level then the output again will pull low. The device is available in a TO9 package for through hole applications as well as SOT3 for surface mount requirements. ZSM3 FEATURES SOT3 and TO9 packages Power on reset generator Automatic reset generation Low standby current Guaranteed operation from 1 volt Wide supply voltage range Internal clamp diode to discharge delay capacitor.63 volt threshold for 3 volt logic mv hysteresis prevents erratic operation APPLICATIONS Microprocessor systems Computers Computer peripherals Instrumentation Automotive Battery powered equipment SCHEMATIC DIAGRAM 4-339
ZSM3 ABSOLUTE MAXIMUM RATING Power Dissipation TO9 78mW Input Supply Voltage -1 to 1V SOT3 W(Note ) Offstate Voltage 1V Onstate Sink Current(Note 1) Internally limited Clamp Diode Forward Current(Note 1) 1mA Operating Junction Temperature 15 C Operating Temperature -4 to 85 C Storage Temperature -55 to 15 C TEST CONDITIONS (T amb =5 C for typical values, T amb =-4 to 85 C for min/max values (Note3)) COMPARATOR PARAMETER SYMBOL MIN TYP. MAX. UNITS Threshold Voltage High state output (V cc increasing) V IH.56.64.7 V Threshold Voltage Low state output (V cc decreasing) V IL.56.6.7 V Hysteresis V H.1..5 V OUPUT sink saturation: V OL (V cc =.V, I sink =8.mA).46 1. V (V cc =.V, I sink =.ma).15.4 V (V cc =1.V, I sink =.1mA).5 V Onstate output sink current (V cc, =.V) Offstate output leakage current (V cc, =3V) Clamp diode forward voltage (I f =1mA) Propagation delay (V in 3V to.v, R l =1k, T amb =5 C) TOTAL DEVICE I sink 1 7 6 ma I oh..5 µa V f.6 1. 1.5 V T d.5 µs Operating input voltage range V cc 1. to 6.5 V Quiescent input current (V cc =3V) I q 15 19 µa Note: 1. Maximum package power dissipation must be observed.. Maximum power dissipation for the SOT3 package is calculated assuming that the device is mounted on a PCB measuring inches square. 3. Low duty cycle pulse techniques are used during test to maintain junction temperatures as close to ambient as possible. 4-34
ZSM3 TYPICAL CHARACTERISTICS 5 5 R =1K TA =5 C 4 4 Forward Current (ma) Sink Current (ma) Input Current (µa) 3 1 5 4 3 1 8 6 4-4 C 5 C 4 6 8 1 Input Voltage (V) Input Current vs. Input Voltage -4 C 5 C.4.8 1. 1.6. Saturation Voltage vs. Sink Current 1 Vin=.4V Vin=V Saturation Voltage (V) 5 C -4 C Vout (V) Vin (V) Voltage (V) Threshold Voltage (V) 3 1 1 3 4 5 Input Voltage (V) Voltage vs. Input Voltage RL =1K 3..4 4 1 3 4 Time (µs) Reset Delay Time.65 Upper Threshold.64.63.6 Lower Threshold.61.4.8 1. 1.6. Forward Voltage (V) Clamp Diode Forward Current vs. Voltage.6-4 - 4 6 8 1 Temperature ( C) Threshold Voltage vs. Temperature 4-341
ZSM3 TIMING DIAGRAM Vcc Threshold Voltage 1V Undefined Undefined APPLICATION CIRCUIT Note 4: A time delayed reset can be accomplished with the additional Cd. T DY = RCd ln æ 1 ö V TH (mpu ) T DY =Time (Seconds) 1 V V TH =Microprocessor Reset Threshold è in ø V in =Power Supply Voltage 4-34
ZSM3 CONNECTION DIAGRAMS SOT3 Package Suffix G TO9 Package Suffix C Top View Pin 4 floating or connected to pin Bottom View ORDERING INFORMATION Part Number Package Part Mark ZSM3G SOT3 ZSM3 ZSM3C TO9 ZSM3 Europe Zetex GmbH Streitfeldstraße 19 D-81673 München Germany Americas Asia Pacific Zetex Inc 7 Veterans Memorial Highway Hauppauge, NY 11788 USA Zetex (Asia Ltd) 371-4 Metroplaza Tower 1 Hing Fong Road, Kwai Fong Hong Kong Corporate Headquarters Zetex Semiconductors plc Zetex Technology Park, Chadderton Oldham, OL9 9LL United Kingdom Telefon: (49) 89 45 49 49 Fax: (49) 89 45 49 49 49 europe.sales@zetex.com Telephone: (1) 631 36 Fax: (1) 631 36 8 usa.sales@zetex.com Telephone: (85) 61 611 Fax: (85) 45 494 asia.sales@zetex.com Telephone: (44) 161 6 4444 Fax: (44) 161 6 4446 hq@zetex.com For international sales offices visit /offices Zetex products are distributed worldwide. For details, see /salesnetwork This publication is issued to provide outline information only which (unless agreed by the company in writing) may not be used, applied or reproduced for any purpose or form part of any order or contact or be regarded as a representation relating to the products or services concerned. The company reserves 4-343 the right to alter without notice the specification, design, price or conditions of supply of any product or service.