general description the HT809 is microprocessor (p) supervisory circuits used to monitor the power supplies in p and digital systems. it provides excellent circuit reliability and low cost by eliminating external components and adjustments when used with 5v-powered or 3v-powered circuits. the circuits perform a single function: it asserts a reset signal whenever the vcc supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after vcc has risen above the reset threshold. the reset comparator is designed to ignore fast transients on vcc. reset thresholds suitable for operation with a variety of supply voltages are available. low supply current makes the HT809 ideal for use in portable equipment. the HT809 comes in a 3-pin sot23 package. features ? precision monitoring of 3v, 3.3v, and 5v power-supply voltages ? fully specified over temperature ? 140ms min power-on reset pulse width: reset output ? 10a supply current ? power supply transient immunity ? no external components ? 3-pin sot23 package applications ? computers ? controllers ? intelligent instruments ? critical p and c power monitoring ? adsl ? automotive block diagram HT809 1 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
pin configuration reset v cc 1 2 3 gnd pin description pin name function 1 gnd ground 2 reset reset output remains low while v cc is below the reset threshold, and for 140ms after v cc rises above the reset threshold. 3 v cc supply voltage (+5v, +3.3v, or +3.0v) ordering information part number temp range pin- package reset threshold(v) HT809t -40c to +85c sot23 3.08 HT809s 2.93 HT809r 2.63 absolute maximum ratings terminal voltage (with respect to gnd) vcc ................................................................................................... ....... ....... ....... ....... -0.3v to 6.0v reset............................................................................................ ....... ....... ........ -0.3 v to (vcc+0.3v) input current, vcc........... ................. ............... ................ .............. ....... ....... .. ..... ........... 20ma output current, reset................................................................ ....... ....... ....... ............ 20ma rate of rise, vcc......................................................................... ....... ....... ....... ............ ..100v/s continuous power dissipation (ta = +70c) sot23 (derate above +70c by 4mw/c) ................... ................ .. ....... .. ..... ....... ....... ..... 320mw operating temperature range........... ................ ................ ............ ....... ....... .. ..... ........ ? 40c to +85c storage temperature range............. .................. ............. ............. ...... ....... . ...... ... ........ ? 65c to +160c lead temperature (soldering, 10 seconds) ............. ................. ........... ...... . ....... ....... ........ +300c stresses beyond those listed under ?absolute maxi mum ratings? may cause permanent damage to the device. these are stress ratings only, and functi onal operation of the device at these or any other conditions beyond those indi cated in the operational sections of the specifications is not implied. exposure to absolute maximum rati ng conditions for extended periods may affect device reliability. HT809 2 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
electrical characteristics (v cc = full range, t a = -40c to +85c, unless otherwise noted. typical values are at t a = +25c, v cc = 3.3v for t/s versions, and v cc = 3v for r version.) (note 1) parameter symbo l conditions min typ max unit v cc range t a = 0c to +85c 1.0 5.5 v supply current i cc t a = -40c to +85c v cc < 3.6v, 10 30 a reset threshold v th HT809t t a = +25c 3.04 3.08 3.11 v t a = -40c to +85c 3.00 3.15 HT809s t a = +25c 2.89 2.93 2.96 t a = -40c to +85c 2.85 3.00 HT809r t a = +25c 2.59 2.63 2.66 t a = -40c to +85c 2.55 2.70 reset threshold tempco 30 ppm/ c v cc to reset delay v cc = v th to (v th - 100mv) 20 s reset active timeout period t a = -40c to +85c 140 240 280 ms reset output voltage low vcc 4.5v, isink = 1.2ma, 0.4 v vcc 2.7v, isink = 1.2ma, 0.4 vcc 1.0v, isink = 100ua, 0.3 reset output voltage high v oh v cc 4.5v, i sink = 3.2ma, v cc - 1.5 v v cc 2.7v, i sink = 500ua, 0.8v cc v cc 1.8v, i sink = 150ua, 0.8v cc note 1: production testing done at t a = +25c, over temperature limits guaranteed by design only. HT809 3 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
reset timing diagram typical operating circuit v cc gnd reset HT809 v cc gnd reset input p v cc HT809 4 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
package description sot-23 package outline dimensions HT809 5 of 5 4008-318-123 sales@twtysemi.com http://www.twtysemi.com product specification
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