ts3809/3810 series microprocessor reset circuit 1 / 7 version: c 07 sot - 23 general description the ts3809/3810 series are used for microprocessor ( p) supervisory circuits to monitor the power supplies in p and digital systems. they provide excellent circuit reliability and low cost by eliminati ng external components and adjustments when used with +5v, +3.3v, +3.0v, +2.5v powered circuits. these circuits perform a single function: they assert a reset signal whenever the v cc supply voltage declines below a preset threshold, keeping it asserted fo r at least 200ms after v cc has risen above the reset threshold. reset thresholds suitable for operation with a variety of supply voltages are available. ts3809/3810 series have push pull outputs. ts3809 series have an active low reset output, while the ts3 810 has an active high reset output the reset comparator is designed to ignore fast 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/ 3 810 series ideal for use in portab le equipment. 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 ts 3 809cx x rf sot - 23 3kpcs / 7 reel ts 3 810cx x rf sot - 23 3kpcs / 7 reel 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 25 s supply current guaranteed reset valid to vcc=+1v power supply transient immunity applications battery - operated systems and controllers intelligent instruments critical up and uc power m onitoring portable / battery powered equipment automotive typical application circuit 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 curre nt, 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
ts3809/3810 series microprocessor reset circuit 2 / 7 version: c 07 thermal performance parameter symbol maximum unit thermal resistance from junction to case j c 110 ?/w thermal resistance from junction to ambient ja 250 ?/w note: ja is measured the pcb copper area of approximately 1in 2 (multi - layer). needs to co nnect to v ss pin. electrical specification ( t a = 25 o c, unless otherwise specified. ) parameter conditions symbol min typ max u nit input supply voltage ta= - 4 0 o c ~+85 o c v cc 1.0 -- 6 v supply current v cc = v th +1v i cc -- 25 35 ua ts 3 809 /38 10 cxa 4.54 4.63 4.7 1 ts 3 809 /3 810cxb 4.29 4.38 4.46 ts 3 809 /3 810 cxc 3.92 4.00 4.08 ts 3 809/ 3810 cxd 3.02 3.08 3.15 ts 3 809/ 3810 cxe 2.87 2.93 3.00 ts 3 809/ 3810 cxf 2.57 2.63 2.69 reset threshold ts3809/3810cxg v th 2.20 2.25 2.30 v reset threshold temper ature coefficient t a =0~+85 c v th t -- 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~+85 c t delay 140 200 260 ms 1.8v< v cc v th(max) , i source =500a v oh 0.8 vcc -- -- v ( reset ) output (ts810) voltage low v cc > v th(max) , i sink =1.2ma v ol -- - - 0. 3 v 1.8v< v cc ts3809/3810 series microprocessor reset circuit 3 / 7 version: c 07 block diagram marking information part no. i dentification code part no. identification code ts 3 809cx a ca ts 3 810cx a ch ts 3 809cx b cb ts 3 810cx b ci ts 3 809cx c cc ts 3 810cx c cj ts 3 809cx d cd ts 3 810cx d ck ts 3 809cx e ce ts 3 810cx e cl ts 3 809cx f cf ts 3 810cx f cm ts3809cxg cg ts3810cxg cn
ts3809/3810 series microprocessor reset circuit 4 / 7 version: c 07 applicati on information negative - going vcc transients in addition to issuing a reset to the p during power - up, power - down, and brownout conditions, the ts 3 809/ 3 810 are relatively immune to short - duration negative - going vcc transients (glitches). the ts 3 809/ 3 810 do not generate a reset pulse. the graph was generated using a negative going pulse applied to vcc, starting 0.5v above the actual reset threshold and ending below it by the magnitude indicated (reset comparator overdrive). the graph indicates the maximum pu lse width a negative going vcc transient can have without causing a reset pulse. as the magnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. typically, a vcc transient that goes 100mv b elow the reset 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 transient immunity. function description a microprocessor s ( p s) reset input starts th e p i n a know state. the ts 3 809/ 3 810 assert reset to prevent code - execution errors during power - up, power - down, or brownout conditions. they assert a reset signal whenever the vcc supply voltage declines below a preset threshold, keeping it asserted for a t least 140ms after vcc has risen above the reset threshold. the ts 3 809/ 3 810 have a push - pull output stage. ensuring a valid reset output down to vcc=0 reset is guaranteed to be a logic low for vcc > 1.0v. once vcc exceeds the reset threshold, an internal timer keeps reset low for the reset timeout period; after this interval, reset goes high. if a brownout condition occurs (vcc dips below the reset threshold), reset goes low. any time vcc goes below the reset threshold, the internal timer resets to zero, and reset goes low. the internal timer starts after vcc returns above the reset threshold, and reset remains low for the reset timeout period. when vcc falls below 1v, the ts 3 809/ 3 810 reset output no longer sinks current - it becomes an open circuit. there fore, high impedance cmos logic input connected 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 applications where reset must be valid down to 0v, adding a pull down resistor to reset causes and stray leakage currents to flow to ground, holding reset low (figure 2.) r1 s value is not critical; 100k is large enough not to load reset and small enough to pull reset to ground. for the ts 3 809/ 3 810 if reset is required to remain valid for vcc<1v. benefits of highly accurate reset threshold most p supervisor ics has reset threshold voltages between 5% and 10% below the value of nominal supply voltages. this ensures a reset will not occur within 5% of the nominal supply, but will occur when the supply is 10% below nominal. when using ics rated at only the nominal supply 5%, this leaves a zon e of uncertainty where the supply is between 5% and 10% low, and where the reset many or may not be asserted timming diagram
ts3809/3810 series microprocessor reset circuit 5 / 7 version: c 07 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
ts3809/3810 series microprocessor reset circuit 6 / 7 version: c 07 sot - 23 mechanical drawing sot - 23 dimension millimeters inches dim 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 5 10 5 10
ts3809/3810 series microprocessor reset circuit 7 / 7 version: c 07 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 errors or inaccuracies. information contained herein is intended to p rovide a product description only. no license, express or implied, to any intellectual property rights is granted by this document. except as provided in tsc? terms and conditions of sale for such products, tsc assumes no liability whatsoever, and disclai ms any express or implied warranty, relating to sale and/or use of tsc products including liability or warranties relating to fitness for a particular purpose, merchantability, or infringement of any patent, copyright, or other intellectual property right. the products shown herein are not designed for use in medical, life - saving, or life - sustaining applications. customers using or selling these products for use in such applications do so at their own risk and agree to fully indemnify tsc for any damages r esulting from such improper use or sale.
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