System Reset with Delay Time Circuit Monolithic IC PST596~598 Series

Transcription

1 System Reset with Delay Time Circuit Monolithic IC 96~98 Series July 21, 2000 Outline This IC functions in a variety of CPU systems and other logic systems, to detect supply voltage and reset the system accurately when the power is turned on or interrupted. It incorporates a fixed-delay time generation circuit. In particular, this IC is a system reset IC which realizes ultra-small size and low current consumption. Features 1. Fixed delay time setting by counter timer 2. Low operating limit voltage 0.6 typ. 3. Hysteresis voltage provided for detection voltage 0m typ.. Low current consumption ICCH=1µA typ.. 3 models are available for different delay times. 96 0ms ms ms 6. Each model has 10 detection voltage ranks. C :. typ. H : 3.1 typ. D :.2 typ. I : 2.9 typ. E : 3.9 typ. J : 2.7 typ. F : 3.6 typ. K : 2. typ. G : 3.3 typ. L : 2.3 typ. Package SOT-2A (9 N) (with manual reset pin) *The box represents a rank of detection voltage. Applications 1. Reset circuits for microcomputers, CPUs and MPUs 2. Reset circuits for logic circuits 3. Battery voltage check circuits. Back-up power supply switching circuits. Level detection circuits 6. Mechanical reset circuits

2 Equivalent Circuit Diagram Delay OSC T Q R OUT 3 GND M/R 1 2 SUB Pin Assignment 1 M/R 2 SUB 3 GND OUT SOT-2 (TOP IEW) Pin Description Pin No. Pin name Function 1 M/R Manual reset pin 1 2 SUB SUB pin 2 3 GND GND pin OUT Reset signal output pin Power supply pin/oltage detection pin 1 : Note that the oscilloscope may mis-operate if the M/R pin falls below : Connect to GND. Absolute Maximum Ratings (Except where noted otherwise Ta=2 C) Item Symbol Ratings Units Storage temperature TSTG - 0~+12 C Operating temperature TOPR 20~+7 C Power supply voltage max. 0.3~+12 Manual reset input voltage RES max. 0.3~+12 Allowable loss Pd 10 mw

3 Recommended Operating Conditions Item Symbol Ratings Units Operating temperature TOPR -20~+7 C Power supply voltage - 0.3~+12 Electrical Characteristics (Ta=2 C) (Except where noted otherwise, resistance unit is Ω) Item Symbol Measuring circuit Measurement conditions Min. Typ. Max. Units C.3..7 D.0.2. E Detection voltage s 1 F =H L G RL=70 H OL 0. I J K L Hysteresis voltage s 1 =L H L, RL= m Detection voltage temperature coefficient s/ T 1 RL=70, Ta= 20 C~+7 C ± 0.01 %/ C Low-level output voltage OL 1 =s min. 0.0, RL= Output leakage current IOH 1 =10 ±0.1 µa Circuit current while on ICCL 1 =s min. 0.0, RL= µa Circuit current while off ICCH 1 =s typ. / 0.8, RL= 1 2 µa RL=.7k "H" transport delay time TPLH 2 CL=100pF ms "L" transport delay time TPHL 2 RL=.7k, CL=100pF, 2 20 µs Operating power supply voltage OPL 1 RL=.7k, OL Output current while on 1 IOL1 1 =s min. 0.0, RL=0 8 ma Output current while on 2 IOL2 1 =s min. 0.0, RL=0 Ta= 20~+7 C 6 ma M/R pin input H voltage RESH 2.0 M/R pin input H current IRESH RESH= µa M/R pin input low voltage RESL : TPLH ; = (s typ. 0.) (s typ.+0.) 2 : TPLH ; = (s typ.+0.) (s typ. 0.) Note 3: Connect manual reset pin to GND when not using.

4 Measuring Circuit [1] [2] A1 A2 RL RL INPUT /10 PULSE 9X +.0 CL=100pF CRT 10µF µF /10 9X RES 2 A : DC ammeter : DC voltmeter CRT : Osciloscope INPUT PULSE typ +0. typ Timing Chart OUT TPLH TPLH TPLH RES M/R Note : Thoroughly check the actual operation of the circuit, then set the manual reset when pressing the manual switch ON to about 1µs. Time

5 Application Circuits 1. Normal hard reset To RL To CPU reset pin 9X Note : Connect a capacitor between IC and GND pins if line impedance is high. 2. Manual reset To Manual SW Clamp Diode( * ) RL To CPU reset pin 9X OUT pin low for manual switch ON. OUT pin high for manual switch OFF. Note1 : Mount a clamp diode if it is possible that the M/R pin might go below 0.3. Note2 : Thoroughly check the actual operation of the circuit, then set the manual reset when pressing the manual switch ON to about 1µs. Characteristics OUT OUT