System Reset PST611 MITSUMI System Reset Monolithic IC PST611 Outline This IC functions in a variety of CPU systems and other logic systems, to constantly monitor power supply voltage, and to reset the system accurately when power is turned on or interrupted. System reset ICs have been represented by the PST series in the past, but this IC is able to set no-response time through an external capacitor, and controls reset output relative to temporary power supply voltage drop caused by motor load or the like in systems using batteries. Also, the detection voltage for this IC is set low so that it can respond to systems that operate on low voltage. Features 1. 2. 3. 4. 5. Low current consumption Low operating limit voltage High reset output No-response time can be controlled 8 types of detection voltages provided ICCH=2.2µA 0.75V max. ICCL=3.2µA PST611 R : 1.6V typ. S : 1.5V typ. T : 1.4V typ. U : 1.3V typ. V : 1.2V typ. W : 1.1V typ. X : 1.0V typ. Y : 0.9V typ. Package MMP-4A (PST611 M) contains detection voltage rank. * Applications 1. 2. 3. 4. Reset circuits in microcomputers, CPUs and MPUs Set voltage drop detection Battery voltage check circuits. Voltage detection circuits in general Absolute Maximum Ratings (Ta=25°C) Item Symbol Rating Units Storage temperature TSTG -40~+125 °C Operating temperature TOPR -10~+70 °C Power supply voltage VCC max. -0.3~+5 V Allowable loss Pd 200 mW System Reset PST611 MITSUMI Electrical Characteristics (Ta=25°C) Item Symbol ICCH ICCL Measurement conditions VCC=0.95V, VR=OPEN VCC=1.2V, VR=OPEN R S T U VCC: variable=3V V W X Y VCC=1.2V, VTC=0.4V, VR=3V VCC=0.95V, VTC=0.1V, VR=3V VCC=0V, VTC=0.1V, VR=0V Max. Units µA Consumption current µA 1.648 V 1.545 V 1.442 V 1.339 V Detection voltage Vs 1.236 V 1.133 V 1.030 V 0.927 V µA TC pin charge current ITC1 µA TC pin discharge current ITC2 66 MEGΩ TC pin discharge resistance RTC Detection voltage temperature coefficient Vs ppm VCC=1.0V, VTC: variable=3V 0.10 V TC pin threshold VTHTC TC pin hysteresis voltage VTHTCH VCC=1.0V, VTC : variable=3V 0.12 V R output leakage current ILEAK VCC=0.95V, VR=3V 0.1 µA R output sync current IOL VCC=1.0V, VTC=0.4V, VR=0.4V 15 50 µA Operation limit voltage VOPL VCC : variable VTC=0.4V, VR=3V 0.7 0.75 V Note: Characteristics other than for detection voltage use the 1.0V(X) type as a representative example. Pin Assignment 4 3 1 2 MMP-4A Equivalent Circuit Diagram 1 ROUT 2 VCC 3 TC 4 GND Min. Typ. 2.2 3.2 1.552 1.6 1.455 1.5 1.358 1.4 1.261 1.3 1.164 1.2 1.067 1.1 0.970 1.0 0.873 0.9 0.1 0.05 16 33 ±200 0.06 0.08 0.06 0.09 System Reset PST611 MITSUMI Measuring Circuit Measurement Method Measurement conditions Item Consumption current VCC VTC VR SW1 SW2 1.2V - - OFF 3 Measured Reference value A1 Measure A1 value. Gradually lower VCC from Detection voltage Variable - 3V OFF 1 V1 1.2V and measure the value of V1 when V2 value switches from low to high. TC pin charge current 1.2V 0.4V 3V ON 1 A2 Measure A2 value. TC pin discharge current 0.95V 0.2V 3V ON 1 A2 Measure A2 value. TC pin discharge resistance 0V 0.1V 0V ON 1 A2 0.1V/A2 value Gradually lower VTC from 0.3V and measure the value TC pin threshold 1.0V Variable 3V ON 1 V3 of V3 when V2 value switches from low to high. (VTHTC) The value of V3 when V2 TC pin hysteresis voltage 1.0V Variable 3V ON 1 V3 switches from high to low while raising VTC from 0.0V, minus "VTHTC." R output leakage current 0.95V - 3V OFF 2 A3 Measure A3K value. R output sync current 1.0V 0.4V 0.4V ON 2 A3 Measure A3 value. The limit voltage within Operation limit voltage Variable 0.4V 3V OFF 1 V1 which V2 value stays low while lowering VCC from 1.0V. System Reset PST611 MITSUMI Delay Characteristics T2 (100mS) Ct=0.01µF VCC V3 T3 0.7V T1 (20mS) ROUT Note 1: Delay times T1 and T2 are found from the formulae below. T1 (S)=CTx (2.0x106) T2 (S)=CTx107 Note 2: ROUT is not output if VCC is temporarily lower than VS. Application circuits Rise delay time (T1) and No-response time (T2) using external capacitor Delay time (mS) 10000.00 1000.00 T2 100.00 T1 10.00 1.00 0.0001 0.001 0.01 0.1 External capacitance C 1 (µF) MITSUMI System Reset PST611 Application circuits 1. How to change reset output logic Note: Set R1 so that V1 > threshold voltage. 2. How to change detection voltage (detection voltage UP) Note: Set R1 so that the value of I1 is sufficient to ignore ICC. 3 Battery checker (LED ON for high voltage) Note: When VCC is less than LED VF, take LED lamp power from DC-DC converter or other output.