mft RT8H062E 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). features miniaturization of a set watch dog timer variable power on reset voltage low consumption typ e0.6matyp,vcc=3.3v wide range of power supplyvccmax=10v open collector output application microcomputer systems recommended operating conditions supply voltage3.3v5v block diaglam of mft , application circuit examples 110805 1 4 watch dog timer vcc wd c tc delay delay out gnd wdt c delay c tc c c r unitmm delay wd gnd r vcc tc out c pin configuration outline drawing isahaya electronics corporation
mft RT8H062E terminal function absolute maximum ratings(ta25) electrical characteristic(ta=25, vcc=3.3v unless otherwise not ed.) ua v v v ua ua v v v ua v v 110805 2 4 watch dog timer 0.50 mw 360 idelay vosat2 out saturation voltage2 vcc=3vtc=3vi=1ma out saturation voltage1 typ max designed value 0.10 min threshold voltage of tc high charge current of delay out=vcc-100k?outlh threshold voltage of wd wd input current output current c threshold voltage of tc low threshold voltage of delay gnd out=vcc-100k?outhl test conditions out=vcc-100k?outlh storage temperature output currentout internal power dissipation ratings 10 c tc delay out 2.62 80 delay=0v clh wd=3v vcc=1.2vi=1ma wd=3vc=0.3v out=vcc-100k?outhl out=vcc-100k?outlh circuit current vtcthl icc vsh vsl vcc detective voltage at high vcc detective voltage at low vosat1 vwdth iwd ic vtcthh vdth 10 200 -20+75 -40+150 unit v v ma topr tstg symbol parameter -0.3vcc operating temperature symbol vcc vin parameter supply voltage input voltagewd,c,tc,delay iout pd terminal no. undecided to set power on reset time. connection capacity terminal to set watch dog time terminal to set abnormal high section of watch dog input terminal watch dog input terminal to change vcc detective voltage terminal suply voltage terminal if input abnormal watch dog signal, then it output reset signal . grand teerminal symbol vcc r wd function 600 2.87 2.76 1.3 160 20 1.5 2.73 1.1 1.2 5 0.12 2.90 0.50 320 unit 840 3.01 isahaya electronics corporation
mft RT8H062E timing diagram notes 1the vcc rises up to detective voltage(vsh), then reset is rel eased. 2out terminal(open collector) generate high signal, after tdou t time decided from capacity at delay terminal. charge of tc begins. t dout [s]Pcdelay[f]1.2[v]5e-6[a] 3this mft watch wd signal from when tc rises up from vtcthl to vtcthh. if no signal input wd, out terminal generate low signa l. t wd [s]P0.236c tc [f]r[] 4when tc falls to vtcthl, out terminal generate high signal. t rst [s]P100c tc [f] 5due to the power failure etc, vcc falls to vsl, out terminal generate low signal. 6vcc rises up to vsh, out terminal generate high signal (if no cdelay capacity). 7if normal clock signal is entered in twd time, tc terminal is decharged. and if tc terminal falls to vtcthl, tc begins chaer ge. 8if no signal is entered in twd time, out terminal generate lo w signal. 9when vcc falls to vsl, out terminal generate low signal. *about c terminal please connect capacity c terminal-gnd terminal always. this ca pacity is always necessary for detected edge of wd signal and, for detected abnormal state of wd's high fixation, this ca pacity can detect normal time of wd's high fixation. twdh [s]P30000c c [f] when high signal is entered in wd terminal, twdh[s] or more, t c terminal begins charge, and begin operate 3. 110805 3 4 watch dog timer t rst t wd vcc tc out wd 1 3 4 5 6 7 8 9 vsh vtcthh vtcthl vsl 2 t dout isahaya electronics corporation
mft RT8H062E about vcc detective voltage (r terminal) if change radj, vcc detective voltage is variable. vshP(1+17.5k/combined resistance between point agnd )1.32v vslP1+17.5k/combined resistance between point agnd )1.25v thermal derating 110805 4 4 watch dog timer at 3.3k pull down vcc detective voltage at open 4.15v 2.87v vsh vsl 2.76v 3.98v 0 25 50 75 100 125 150 250 200 150 100 50 0 ambient temperature ta [] power dissipation pd[w] 17.5k 15k 15k r vcc radj 1.25v a 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 th at 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 appropri ate measures such as ( 1) placement of substitutive, auxiliary, ( 2) use of non - farmable material or ( 3) prevention against any malfunct ion or mishap. notes regarding these materials these materials are intended as a reference to our customers in the selection of the isah aya products best suited to the customer?s application; they don't convey any license under any intellectual prop erty rights, or any other rights, belonging isahaya or third party. isahaya electronics corporation assumes no responsibility for any damage, or infringement of any third party's rights , originating in the use of any product data, diagram s, charts or circuit application examples contained in these materials . all information contained in these materials, including product data, diagrams and charts, represent information on products at the time of publication of these materials, a nd are subject to change by isahaya electronics corporation without notice due to product improvements or other reasons. it is therefore recommended that customers contact isahaya electronics corporation or an authorized isahaya products distr ibutor for the latest product information before purchasing product listed herein. isahaya electronics corporation products are not designed or manufactured for use in a device or system that is used under circumstances in which human lif e is potentially at stake. please contact isahaya electronics corporation or an authorized isahaya products distributor when considering the use of a product contained herein for any specific purposes , such as apparatus or systems for transpor tation, vehicular, medical, aerospace, nuclear, or undersea repeater use. the prior written approval of isahaya electronics corporation is necessary to reprint or reproduce in whole or in part these materials. if these products or technolo gies are subject to the japanese export control restrictions, they must be exported under a license from the japanese government and cannot be imported into a country other than the approved destination. any diversion or re - export contrary to t he export control laws and regulations of japan and/or the country of destination is prohibited. please contact isahaya electronics corporation or authorized isahaya products distributor for further details on these materials or the product s contained therein. aug.2011
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