＜M F T＞ RT8H062E WATCH DOG TIMER DESCRIPTION RT8H062E is a semiconductor integrated circuit which is designed for System Reset to detect +3.3V、+5V power supply. This MFT keeps the operation of micro computer watching. The system circuit current at normal state is low consumption type of 0.6mA(Typical). OUTLINE DRAWING FEATURES ● Miniaturization of a set ● Watch Dog Timer ● Variable power on reset voltage ● Low consumption type：0.6mA（Typ,VCC=3.3V） ● Wide range of power supply：VCC（MAX）=10V ● Open collector output APPLICATION ● Microcomputer Systems Unit：mm PIN CONFIGURATION ① ② ③ ④ RECOMMENDED OPERATING CONDITIONS ● Supply voltage：3.3V、5V ⑧ ⑦ ⑥ ⑤ ①Delay ②WD ③GND ④R ⑧VCC ⑦TC ⑥OUT ⑤C BLOCK DIAGLAM OF MFT , APPLICATION CIRCUIT EXAMPLES CDelay Delay TC CTC VCC OUT R Delay WDT GND WD C CC 110805 （1／4） ISAHAYA ELECTRONICS CORPORATION ＜M F T＞ RT8H062E WATCH DOG TIMER TERMINAL FUNCTION Terminal No. Undecided Symbol VCC R WD C TC Delay OUT GND Function Suply voltage terminal To change vcc detective voltage terminal Watch dog input terminal To set abnormal high section of watch dog input terminal To set watch dog time terminal To set power on reset time. Connection capacity terminal If input abnormal watch dog signal, then it output reset signal. Grand teerminal ABSOLUTE MAXIMUM RATINGS (Ta＝25℃) Symbol VCC VIN IOUT Pd Topr Tstg Ratings 10 -0.3～VCC 10 200 -20～+75 -40～+150 Parameter Supply voltage Input voltage（WD,C,TC,Delay） Output current（OUT） Internal power dissipation Operating temperature Storage temperature Unit V V mA mW ℃ ℃ ELECTRICAL CHARACTERISTIC (Ta=25℃,VCC=3.3V unless otherwise noted.) Symbol ICC VsH VsL VWDth IWD IC VTCthH VTCthL VDth IDelay VOsat1 VOsat2 Parameter Test conditions Circuit current VCC detective voltage at High OUT=VCC-100kΩ、OUT：L→H VCC detective voltage at Low OUT=VCC-100kΩ、OUT：H→L C：L→H WD=3V WD=3V、C=0.3V Threshold voltage of TC HIGH OUT=VCC-100kΩ、OUT：H→L Threshold voltage of TC LOW OUT=VCC-100kΩ、OUT：L→H Threshold voltage of Delay OUT=VCC-100kΩ、OUT：L→H Charge current of Delay Delay=0V OUT saturation voltage1 VCC=1.2V、I=1mA OUT saturation voltage2 VCC=3V、TC=3V、I=1mA Threshold voltage of WD WD input current Output current C Min 360 2.73 2.62 80 Designed value Typ 600 2.87 2.76 1.3 160 20 1.5 1.1 1.2 5 0.12 0.10 Max 840 3.01 2.90 320 0.50 0.50 110805 （2／4） ISAHAYA ELECTRONICS CORPORATION Unit uA V V V uA uA V V V uA V V ＜M F T＞ RT8H062E WATCH DOG TIMER TIMING DIAGRAM VCC VsH VsL VTCthH TC VTCthL tRST WD tDOUT OUT tWD 1 2 34 56 7 8 9 NOTES 1．The VCC rises up to detective voltage(VsH), then reset is released. 2．OUT terminal(Open collector) generate High signal, after tDOUT time decided from capacity at Delay terminal. Charge of TC begins. tDOUT [s]≒Cdelay[F]×1.2[V]÷5E-6[A] 3．This MFT watch WD signal from when TC rises up from VTCthL to VTCthH. If no signal input WD, OUT terminal generate Low signal. tWD[s]≒0.236×C TC [F]×R[Ω] 4．When TC falls to VTCthL, OUT terminal generate High signal. tRST [s]≒100×C TC [F] 5．Due to the power failure etc, VCC falls to VsL, OUT terminal generate Low signal. 6．VCC rises up to VsH, OUT terminal generate High signal (if no Cdelay capacity). 7．If normal clock signal is entered in twd time, TC terminal is decharged. And if TC terminal falls to VTCthL, TC begins chaerge. 8．If no signal is entered in twd time, OUT terminal generate Low signal. 9．When VCC falls to VsL, OUT terminal generate Low signal. *About C terminal Please connect capacity C terminal-GND terminal always. This capacity is always necessary for detected edge of WD signal And, for detected abnormal state of WD's high fixation, This capacity can detect normal time of WD's high fixation. twdh [s]≒30000×C C[F] When High signal is entered in WD terminal, twdh[s] or more, TC terminal begins charge, and begin operate 3．. 110805 （3／4） ISAHAYA ELECTRONICS CORPORATION ＜M F T＞ RT8H062E WATCH DOG TIMER About VCC detective voltage (R terminal) VCC detective voltage VsH VsL At Open 2.87V 2.76V At 3.3kΩ pull down 4.15V 3.98V If change Radj, VCC detective voltage is variable. VCC VsH≒(1+17.5k/Combined resistance between point A～GND )×1.32V 17.5kΩ R Radj 15kΩ VsL≒1+17.5k/Combined resistance between point A～GND )×1.25V A 15kΩ 1.25V THERMAL DERATING POWER DISSIPATION Pd[ｍW] 250 200 150 100 50 0 0 25 50 75 100 125 150 AMBIENT TEMPERATURE Ta [℃] 110805 （4／4） ISAHAYA ELECTRONICS CORPORATION 6-41 Tsukuba, Isahaya, Nagasaki, 854-0065 Japan Keep safety first in your circuit designs! ·ISAHAYA Electronics Corporation puts the maximum effort into making semiconductor products better and more reliable, but there is always the possibility that trouble may occur with them. Trouble with semiconductors may lead to personal injury, fire or property damage. Remember to give due consideration to safety when making your circuit designs, with appropriate measures such as (1) placement of substitutive, auxiliary, (2) use of non-farmable material or (3) prevention against any malfunction or mishap. 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