ts3809/3810 series microprocessor reset circuit 1/7 version: d11 sot - 23 general description the ts3809/3810 series are used for microprocessor (p) supervisory circuits to monitor the power supp lies in p and digital systems. they provide excellent circuit reliability and low cost by eliminating external c omponents and adjustments when used with +5v, +3.3v, +3.0v, +2.5v powered circuits. these circuits perform a single function: they asse rt a reset signal whenever the v cc supply voltage declines below a preset threshold, keeping it asserted for a t least 200ms after v cc has risen above the reset threshold. reset thresholds suitable for operation with a vari ety of supply voltages are available. ts3809/3810 s eries have push pull outputs. ts3809 series have an active low reset output, while the ts3810 has an active high reset output the reset comparator is designed to ignore f ast transients on v cc , and the outputs are guaranteed to be in the correct logic state for v cc down to 1.0v. low supply current makes ts3809/3810 series ideal for use in portable equipment. features high accurate: 2% precision monitoring of +3v, +3.3v and +5v power supply voltage fully specified over temperature available in three output configurations push-pull reset low output (ts3809) push-pull (reset) high output (ts3810) 200ms typ. power-on reset pulse width 25s supply current guaranteed reset valid to vcc=+1v power supply transient immunity ordering information note: x is the threshold voltage type, option as: a : 4.63v b : 4.38v c : 4.00v d : 3.08v e : 2.93v f : 2.63v g : 2.25v part no. package packing ts3809cx x rf sot-23 3kpcs / 7 reel ts3810cx x rf sot-23 3kpcs / 7 reel typical application circuit applications battery-operated systems and controllers intelligent instruments critical up and uc power monitoring portable / battery powered equipment automotive absolute maximum rating parameter symbol maximum unit terminal voltage (with respect to gnd) v cc gnd - 0.3 to gnd +6.5 v reset & (reset) push-pull v reset gnd - 0.3 to v cc +0.3 v input current, v cc i cc 20 ma output current, reset, (reset) i o 5 ma power dissipation p d (t j -t a )/ ja mw operating junction temperature range t j.o p r -40 ~ +125 o c storage temperature range t stg -65 ~ +150 o c lead soldering temperature (260 o c) t lead 10 s pin definition : ts3809 ts3810 1. gnd 1. gnd 2. reset 2. (reset) 3. vcc 3. vcc downloaded from: http:///
ts3809/3810 series microprocessor reset circuit 2/7 version: d11 thermal performance parameter symbol maximum unit thermal resistance from junction to case j c 110 oc/w thermal resistance from junction to ambient ja 250 oc/w note: ? ja is measured the pcb copper area of approximately 1 in 2 (multi-layer). needs to connect to v ss pin. electrical specification ( ta = 25 o c, unless otherwise specified.) parameter conditions symbol min typ max unit input supply voltage ta=-40 o c~+85 o c v cc 1.0 -- 6 v supply current v cc =v th +1v i cc -- 25 35 ua reset threshold ts3809/3810cxa v th 4.54 4.63 4.71 v ts3809/3810cxb 4.29 4.38 4.46 ts3809/3810cxc 3.92 4.00 4.08 ts3809/3810cxd 3.02 3.08 3.15 ts3809/3810cxe 2.87 2.93 3.00 ts3809/3810cxf 2.57 2.63 2.69 ts3809/3810cxg 2.20 2.25 2.30 reset threshold temperature coefficient t a =0~+85oc v tht -- 50 -- ppm/ o c set-up time v cc = 0 ~ (v th - 100mv) t s et 1 -- -- s vcc to reset delay v cc = v th ~ (v th - 100mv) t rd -- 20 -- s reset active timeout period t a =0~+85oc t delay 140 200 260 ms reset output (ts3809) voltage low 1.8v v th(max) , i source =500a v oh 0.8 vcc -- -- v (reset) output (ts3810) voltage low v cc > v th(max) , i sink =1.2ma v ol -- -- 0.3 v (reset) output (ts3810) voltage high 1.8v ts3809/3810 series microprocessor reset circuit 3/7 version: d11 block diagram device top marking information part no. identification code part no. identification code ts3809cxa ca ts3810cxa ch ts3809cxb cb ts3810cxb ci TS3809CXC cc ts3810cxc cj ts3809cxd cd ts3810cxd ck ts3809cxe ce ts3810cxe cl ts3809cxf cf ts3810cxf cm ts3809cxg cg ts3810cxg cn downloaded from: http:///
ts3809/3810 series microprocessor reset circuit 4/7 version: d11 application information negative-going vcc transients in addition to issuin g a reset to the p during power-up, power-down, and brownout conditions, the ts3809/3810 are relatively immune to short-duration negative-going vcc transi ents (glitches). the ts3809/3810 do not generate a reset pulse. the graph was generated using a negative going pulse ap plied to vcc, starting 0.5v above the actual reset threshold and ending below it by the magnitude indicated (re set comparator overdrive). the graph indicates the maxi mum pulse width a negative going vcc transient can have without causing a reset pulse. as the magnitude of the transient increases (goes farther below the res et threshold), the maximum allowable pulse width decreases. typica lly, a vcc transient that goes 100mv below the rese t threshold and lasts 20 s or less will not cause a reset pulse. a 0.1 f bypass capacitor mounted as close as possible to the vcc pin provides additional transie nt immunity. function description a microprocessors ( ps) reset input starts the p in a know state. the ts3809/3810 assert reset to prevent code- execution errors during power-up, power-down, or br ownout conditions. they assert a reset signal whene ver the vcc supply voltage declines below a preset threshol d, keeping it asserted for at least 140ms after vcc has risen above the reset threshold. the ts3809/3810 have a p ush-pull output stage. ensuring a valid reset output down to vcc=0 reset is guaranteed to be a logic low for vcc > 1.0 v. once vcc exceeds the reset threshold, an interna l timer keeps reset low for the reset timeout period; after this interval, reset goes high. if a brownout cond ition occurs (vcc dips below the reset threshold), reset goes lo w. any time vcc goes below the reset threshold, the internal timer resets to zero, and reset goes low. the inter nal timer starts after vcc returns above the reset threshold, and reset remains low for the reset timeout period. when vcc falls below 1v, the ts3809/3810 reset out put no longer sinks current - it becomes an open circuit. therefore, high impedance cmos logic input connecte d to reset can drift to undetermined voltages. this present no problem in most applications since most p and other circuitry is inoperative with vcc below 1v.however, in applic ations where reset must be valid down to 0v, adding a pull down resistor to reset causes and stray leakage cur rents to flow to ground, holding reset low (figure 2.) r1s value is not critical; 100k is large enough not to load r eset and small enough to pull reset to ground. for the ts3809/3810 if reset is required to remain valid fo r vcc<1v. benefits of highly accurate reset threshold most p supervisor ics has reset threshold voltages betwe en 5% and 10% below the value of nominal supply voltages. this ensures a reset will not occur withi n 5% of the nominal supply, but will occur when the supply is 10% below nominal. when using ics rated at only the nom inal supply 5%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the res et many or may not be asserted timming diagram downloaded from: http:///
ts3809/3810 series microprocessor reset circuit 5/7 version: d11 electrical characteristics curve figure 1. threshold voltage vs. temperature figure 2. t delay vs. temperature figure 3. supply current vs. temperature figure 4. supply current vs. threshold voltage figure 5. power-down t delay vs. temperature figure 6. output voltage vs. output current downloaded from: http:///
ts3809/3810 series microprocessor reset circuit 6/7 version: d11 sot-23 mechanical drawing sot-23 dimension dim millimeters inches min max min max. a 0.95 bsc 0.037 bsc a1 1.9 bsc 0.074 bsc b 2.60 3.00 0.102 0.118 c 1.40 1.70 0.055 0.067 d 2.80 3.10 0.110 0.122 e 1.00 1.30 0.039 0.051 f 0.00 0.10 0.000 0.004 g 0.35 0.50 0.014 0.020 h 0.10 0.20 0.004 0.008 i 0.30 0.60 0.012 0.024 j 5o 10o 5o 10o downloaded from: http:///
ts3809/3810 series microprocessor reset circuit 7/7 version: d11 notice specifications of the products displayed herein are subject to change without notice. tsc or anyone on its behalf, assumes no responsibility or liability for any erro rs or inaccuracies. information contained herein is intended to provide a product description only. no license, express or implied, to any intellectual property rights is granted by this document. except as provided in tscs terms and co nditions of sale for such products, tsc assumes no liability wh atsoever, and disclaims any express or implied warr anty, relating to sale and/or use of tsc products includi ng liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, cop yright, or other intellectual property right. the products shown herein are not designed for use in medical, life-saving, or life-sustaining applica tions. customers using or selling these products for use i n such applications do so at their own risk and agr ee to fully indemnify tsc for any damages resulting from such i mproper use or sale. downloaded from: http:///
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