SUPPLY VOLTAGE MONITOR ZSM561 ISSUE 3 – JANUARY 1998 DEVICE DESCRIPTION FEATURES The ZSM561 is a three terminal under vo l ta ge mo ni t or ci rc ui t f or use i n microprocessor systems. The threshold voltage of the device has been set to 4.6 volts making it ideal for 5 volt circuits. • • • • • • • Included in the device is a precise voltage reference and a comparator with built in hysteresis to prevent erratic operation. The ZSM561 features an open collector output capable of sinking at least l0mA which only requires a single external resistor to interface to following circuits. • • SO8, SOT223 and TO92 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 4.6 volt threshold for 5 volt logic 20mV hysteresis prevents erratic operation APPLICATIONS 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. Also included is a 6 volt zener diode connected between Vcc and Gnd. With just the addition of a low cost external NPN transistor and resistor, this zener allows the ZSM561 to provide both regulator and supply monitor functions • • • • • • The device is available in a TO92 package for through hole applications as well as SO8 and SOT223 for surface mount requirements. SCHEMATIC DIAGRAM 4-364 Microprocessor systems Computers Computer peripherals Instrumentation Automotive Battery powered equipment ZSM561 ABSOLUTE MAXIMUM RATING Input Supply Voltage Supply Zener Current Offstate Output Voltage Onstate Output Sink Current(Note 1) Clamp Diode Forward Current(Note 1) -1 to 7V 25mA continuous 7V Internally limited 100mA Operating Junction Temperature Operating Temperature Storage Temperature Power Dissipation TO92 SOT223 SO8 150°C -40 to 85°C -65 to 150°C 780mW 2W(Note 2) 780mW(Note 2) TEST CONDITIONS (Tamb=25°C for typical values, Tamb=-40 to 85°C for min/max values (Note3)) COMPARATOR MIN TYP. MAX. PARAMETER SYMBOL UNITS Threshold Voltage High state output (Vcc increasing) VIH 4.5 4.61 4.7 Threshold Voltage Low state output (Vcc decreasing) VIL 4.5 4.59 4.7 V Hysteresis VH 0.01 0.02 0.05 V (Vcc=4.0V, Isink=8.0mA) 0.46 1.0 V (Vcc=4.0V, Isink=2.0mA) 0.15 0.4 V 0.25 V 20 60 mA 0.02 0.5 µA 1.2 1.5 V V OUPUT Output sink saturation: VOL (Vcc=1.0V, Isink=0.1mA) Onstate output sink current (Vcc , Output=4V) Isink Offstate output leakage current (Vcc , Output=5V) Ioh Clamp diode forward voltage (If=10mA) Vf Propagation delay (Vin 5V to 4V, Rl=10k, Tamb=25°C) Td 10 0.6 µs 1.5 SUPPLY ZENER Avalanche Voltage:(Icc=1mA) Slope Resistance: Vz 5.8 (Icc=15mA) Rz (Icc=15mA to 50mA) 6 6.2 V 45 21 60 30 Ω Ω TOTAL DEVICE Operating input voltage range(Note 5) Vcc Quiescent current (Vcc=5V) Iq 1.0 to 7 V 135 4-365 200 µA ZSM561 500 10 400 8 Output Voltage (V) Input Current (µA) TYPICAL CHARACTERISTICS 300 200 100 -40 °C RL=10K TA=25 °C 6 4 2 25 °C 85 °C 0 0 0 4 2 8 6 10 0 2 4 6 8 Input Voltage (V) Input Voltage (V) Input Current vs. Input Voltage Output Voltage vs. Input Voltage 10 30 RL=10K Vin (V) Vin=4V -40 °C 4 ' 25 °C 20 Sink Current (mA) 5 85 °C ' 4 Vout (V) 10 2 0 0 0 0.4 0.8 1.2 1.6 -1 2.0 1 2 Time (µs) Output Saturation Voltage vs. Sink Current Reset Delay Time 80 Vin=0V 60 Forward Current (mA) 0 Output Saturation Voltage (V) 85 °C 40 25 °C -40 °C 20 0 0 0.4 0.8 1.2 1.6 2.0 Forward Voltage (V) Clamp Diode Forward Current vs. Voltage 4-366 3 4 ZSM561 TYPICAL CHARACTERISTICS 4.70 50 4.65 Threshold Voltage (V) Input Current (mA) 40 30 20 Upper Threshold 4.60 Lower Threshold 4.55 10 4.50 -40 0 0 2 4 6 8 10 -20 0 20 40 60 80 100 Temperature ( °C) Input Voltage (V) Threshold Voltage vs. Temperature Input Current vs. Input Voltage TIMING DIAGRAM Vcc Threshold Voltage 1V Output AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAA AAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAAAAAA AAA AAAA AAAAAAA Output Undefined Output Undefined Note: 1. Maximum package power dissipation must be observed. 2. Maximum power dissipation for the SOT223 and SO8 packages is calculated assuming that the device is mounted on a PCB measuring 2 inches square. 3. Low duty cycle pulse techniques are used during test to maintain junction temperatures as close to ambient as possible 4. A time delayed reset can be accomplished with the additional Cd. 5. Operation above Vz may be restricted by the supply current rating Iz 4-367 ZSM561 APPLICATION CIRCUITS 1 TDY = RCd ln 1 − VTH(mpu) Vin RB = TDY = Time (Seconds) VTH = Microprocessor ResetThreshold Vin = Power Supply Voltage (VINMIN − 6) IL (IQ + ) hFE VINMIN = The minimum input voltage provided by the unregulated supply. IQ = The ZSM561 quiescent current (ie 200 µA) IL = Load current taken by the microprocessor system. hFE = The minimum hFE that can be expected from the pass transistor under worst case conditions. (ie Lowest temperature and minimum input voltage). For the ZTX690B a value of 250 could be used. 4-368 ZSM561 CONNECTION DIAGRAMS SO8 Package Suffix – N8 SOT223 Top View Top View – Pin 4 floating or connected to pin 2 TO92 Package Suffix – C Bottom View ORDERING INFORMATION Part Number Package Part Mark ZSM561N8 SO8 ZSM561 ZSM561G SOT223 ZSM561 ZSM561C TO92 ZSM561 4-369 Package Suffix – G