ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 1 / 8 version: c 07 sot - 25 general description t he ts823/824/825 family allows the user to customize the cpu monitoring function without any external components. the user has a large choice of reset voltage thresholds and output driver configura tions, all of which are present ant the factory. each wafer is trimmed to the customer s specifications. these circuits will ignore fast negative going transients on vdd. the state of the reset output is guaranteed to be correct down to 1v. after vdd cross es above a factory present threshold, the ts823/824/825 assert a reset signal. after a predetermined time (the reset interval) the reset is deasserted. if vdd ever drops below the threshold voltage a reset is asserted immediately. in addition to a supply monitoring function the ts823/824/825 also monitor transitions at the watchdog (wdi) input. if a logic transition does not occur at the wdi pin within a certain time interval (the watchdog interval) then a reset is asserted. the reset deasserts after th e reset interval, as explained earlier. t he ts823/824/825 can both assert a reset manually by pulling the mr input to ground, and the micro - power quiescent current make this family a natural for portable battery powered equipment. ordering information note: x is the threshold voltage type, option as a : 4. 63v b : 4.38v d : 3.08v e : 2.93v f : 2.63v g : 2.32v h : 2.19v contact factory for additional voltage option part no. package packing ts823cx5 x rf sot - 25 3kpcs / 7 reel ts824cx5 x rf sot - 25 3kpcs / 7 reel ts825cx5 x rf sot - 25 3kpcs / 7 reel features precision moni toring of +3v, +3.3v and +5v power supply voltage tight voltage threshold tolerance +/ - 1.5% fully specified over temperature 210ms min. power - on reset pulse width 3ua(typ) supply current guaranteed reset valid to vdd = +1v power supply transient immunity no external components applications computers and controllers embedded controllers intelligent instruments critical up monitoring portable / battery powered equipment automotive systems pin descriptions function ts823 ts824 ts825 reset (active - low) 1 1 1 ground 2 2 2 manual reset 3 - 4 (reset) (active - high) - 3 3 watch dog input 4 4 - supply voltage (vdd) 5 5 5 absolute maximum rating parameter symbol ma ximum unit supply voltage vdd 6.0 v supply voltage - recommended vdd 0.9 ~ 5 v operating junction temperature range t op - 40 ~ +125 o c storage temperature range t stg - 65 ~ +150 o c thermal resistance jc 256 o c/w maximum lead temperature (260 o c) t lead 10 s notes: stress above the listed absolute rating may cause permanent damage to the device.
ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 2 / 8 version: c 07 electrical specifications ( ta = 25 o c , unless otherwise noted ) parameter conditions symbol min typ max u nit input supply voltage vdd 1.0 -- 5.5 v supply current wdi and mrb unconnected idd -- 3 10 ua ts823/824/825cx5a 4.56 4.63 4.7 ts823/824/825cx5b 4.31 4.38 4.45 ts823/824/825cx5d 3.03 3.08 3.13 ts823/824/825cx5e 2.89 2. 93 2.97 ts823/824/825cx5f 2.59 2.63 2.67 ts823/824/825cx5g 2.28 2.32 2.36 reset threshold ts823/824/825cx5h v th 2.15 2.19 2.23 v reset output voltage low vdd vth(max), i source =0.5ma v oh 0.8 vdd -- -- v vdd to reset delay vdd =v th - 100mv t d1 -- 40 -- us reset active timeout period ta= - 40 o c ~+85 o c t d2 140 210 280 ms watchdog timeout period t wd 1120 1760 2400 ms wdi pulse width t wdi 50 -- -- ns w diil -- -- 0.7 v wdi input threshold vdd = v th x 1.2 w diih 0.8 vdd -- -- v w di =0v i il - 15 - 8 0.7 ua wdi input current w di =vdd = 5v i ih -- 8 15 ua m ril -- -- 0.7 v mr input threshold vdd=v th x 1.2 m rih 0.8 vdd -- -- v mr pulse width t wmr 1 -- -- us mr noise immunity pulse width wi th no reset -- 100 -- ns mr to reset delay vdd = v th - 100mv t dmr -- 500 -- ns mr pull up resistance 80 -- 120 k input supply voltage ta= - 4 0 o c ~+85 o c v cc 1.0 -- 5.5 v detail description pin function pin name pin description reset active low gnd gr ound (reset) active high mr this pin is active low. pulling this pin low to forces a reset. after a low to high transition reset remains asserted for exactly one reset timeout period. this pin is internally pulled high. if this function is unused then fl oat this pin or tie it to vdd. wdi watch dog input. any transition on this pin will reset the watch dog timer. if this pin remains high or low for longer than the watch dog interval then a reset is asserted. float or tri - state this pin to disable the watc h dog feature. vdd positive power supply. a reset is asserted after this voltage drops below a predetermined level. after vdd rises above that level reset remains asserted until the end of the reset timeout period.
ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 3 / 8 version: c 07 application information the ts823/8 24/825 are designed to interface with the reset input of a microprocessor and to prevent cpu execution errors due to power up, power down, and other power supply errors. the ts823/824 also monitor the cpu health by checking for signal transitions form the cpu at the wdi input. reset output active low reset outputs are denoted as reset, active high reset output are denoted as (reset), a reset will be asserted if any of three things happen: 1. vdd drops below the threshold (vth) 2. the mr pin is pulled low . 3. the wdi pin does not detect a transition within the watch dog interval (twd) the reset will remain asserted for the prescribed reset interval after: 1. vdd rises above the threshold (vth) 2. mr goes high 3. the watch dog timer have timed out causin g the reset to assert. manual reset input the ts823 and ts825 feature a manual reset feature (mr). a logic low on the mr pin asserts a reset. the reset remains asserted a long as the mr pin remains low. after the mr pin transitions to a high state the res et remains asserted for the prescribed reset interval (td2). the mr pin is internally pulled up to vdd by a 100k resistor. it is internally de - bounced to reject switching transients. the mr pin is esd protected by diodes connected to vdd and gnd. so the mr pin should never be driven higher than vdd or lower than gnd. watchdog input the ts823 and ts824 are equipped with a watchdog input (wdi). if the microprocessor does not produce a valid logic edge at the watchdog input (wdi) within the prescribed watchdog interval (twd) then a reset asserts. the reset remains asserted for the required reset interval (td2). ata th e end of the reset interval the reset is deasserted and the watchdog interval timer starts again from zero. if the watchdog input is left unconnected or is connected to a tri - stated buffer the watchdog function is disabled . as soon as the wdi input is driv en either low or high the watchdog function resumes with the watchdog timer set to zero. watchdog input current the watchdog input pin (wdi) typically sources/sinks 8ua when driven high or low. so from a power dissipation point of view the duty cycle of t he waveform at wdi is unimportant. when the wdi pin is floating or tri - stated the power supply current fall to less than 3ua. glitch rejection the ts823/824/825 family will reject negative going transients on the vdd line to some extent. the smaller the du ration of the transient the larger its amplitude may be without triggering a reset. the glitch rejection chart in the graphs section of this datasheet shows the relation between glitch amplitude and allowable glitch duration to avoid unintended resets. a ccurate output state at low vdd with vdd voltage on the order of the mos transistor threshold (<1v) the outputs of the ts823/824/825 may become undefined. for parts with active low output reset a resistor placed between reset and gnd on the order of 100k will ensure that the reset output stays low when vdd is lower than the threshold voltage of the part. in a like manner a resistor on the order of 100k when placed between (reset) and vdd will ensure parts with active high output (reset) will remain high when vdd is lower than the threshold voltage of the parts.
ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 4 / 8 version: c 07 reset timing diagram reset timing diagram
ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 5 / 8 version: c 07 electrical characteristics curve figure 1. glitch rejection figure 2. reset time vs. temperature figure 3. iin vs. temperatur e figure 4. reset vth vs. temperature figure 5. reset vol vs. temperature
ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 6 / 8 version: c 07 marking information part no. identification code part no. identification code part no. identification code ts 823 cx 5a bac ts 824 cx 5a bad ts 825 cx 5a bae ts 823 cx 5b -- ts 824 cx 5b atw ts 825 cx 5b -- ts 823 cx 5d asm ts 824 cx 5d atl ts 825 cx 5d atn ts 823 cx 5e atx ts 824 cx 5e atv ts 825 cx 5e aus ts 823 cx 5f atg ts 824 cx 5f atc ts 825 cx 5f aww ts823cx5g bcw ts824cx5g -- ts825cx5g -- year code definition identification code week code year x x x w w xxx0 x x x w w xxx1 x x x w w xxx2 x x x w w xxx3 x x x w w xxx4 x x x w w xxx5 x x x w w xxx6 x x x w w xxx7 x x x w w xxx8 x x x w w xxx9
ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 7 / 8 version: c 07 sot - 25 mechanical drawing sot - 25 dimension millimeters inches dim min max min max. a+a1 0.09 1.25 0.0354 0.0492 b 0.30 0.50 0.0118 0.0197 c 0.09 0.25 0.0035 0.0098 d 2.70 3.10 0.1063 0.1220 e 1.40 1.80 0.0551 0.0709 e 1.90 bsc 0.0748 bsc h 2.40 3.00 0.09449 0.1181 l 0.35 bsc 0.0138 bsc ? 1 0 10 0 10 s1 0.95 bsc 0.0374 bsc
ts823/824/825 series microprocessor supervisory circuit with watchdog timer & manual reset 8 / 8 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 c ontained 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 tsc s terms and conditions of sale for such products, tsc assumes no l iability whatsoever, and disclaims 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 ot her 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 resulting from such improper use or sale.
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