View MAX823REXK_7601369.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

max823/4/5 voltage supervisor with watchdog timer and manual reset revision 1.0 micrel inc. ? 2180 fortune drive ? san jose, ca 95131 ? usa ? tel +1 (408) 944 - 0800 ? fax + 1 (408) 474 - 1000 ? http://www.micrel.com january 14 , 20 1 4 revision 1.0 general description the max823/4/5 voltage supervisory circuits combine low - cu rrent , manual reset input, watchdog timer, active - high and active - low push - pull outputs. the reset outputs are asserted and held when the supply voltage falls below the factory - programmed threshold voltage, when the /mr pin is pulled low, or if the watchdog times out. reset is asserted for the reset timeout delay after the supply voltage increases above the rising threshold voltage or when manual reset input is asserted high. the max823 /4/5 features an integrated pull - up resistor on the /mr pin. an active - low push - pull reset output (/reset) and an active - high reset output (reset) provide flexibility when interfacing with various microcontrollers, pmics, or load switches. the watchdog input can be left unconnected for applications that do not require watchdog monitoring. the max823/4/5 consumes a quiescent current of only 3. 8 a and is offered in standard sot23 - 5 and sc70 - 5 package s . it is rated for the C 40 c to +125 c temperature range. datasheets and support documentation are available on micrels web site at : www.micrel.com . features ? precision 1.665v to 4.625 v powe r supply monitor ? 0.5% threshold accuracy at ta = +25c ? 1.5% threshold accuracy from ta = C 40c to +125c ? 3.8a supply current (s,r,t,w,y,z options) ? 4.8a supply current (l,m options) ? manual reset input (max823/5) ? 140ms (min.) reset timeout period ? 1.6s ( typ.) watchdog timeout period ? active - high and active - low push - pull outputs ? guaranteed reset output valid to vcc = 1v ? ? 40c to +125c junction temperature range ? 5 - pin sot23 & sc70 packages ? 8x lower watchdog input current than competition applications ? computers and controllers ? embedded controllers ? intelligent instruments ? automotive systems ? critical p monitoring ? portable/ battery - powered equipment typical application
micrel, inc. max823/4/5 january 14, 2014 2 revision 1.0 function max823 max824 max825 active - low reset ? ? ? active - high reset ? ? ? watchdog input ? ? ? manual reset input ? ? ? ordering information ( 1 ) part number top marking v rst : nominal threshold voltage (v) package max823 l euk x3l 4.625 sot23 - 5 max823meuk x3m 4.375 sot23 - 5 max823reuk x3r 2.625 sot23 - 5 max823seuk x3s 2.925 sot23 - 5 max823teuk x3t 3.075 sot23 - 5 max823weuk x3w 1.665 sot23 - 5 max823yeuk x3y 2.188 sot23 - 5 max823zeuk x3z 2.315 sot23 - 5 max823 l exk xa 4.625 sc70 - 5 max823mexk xb 4.375 sc70 - 5 MAX823REXK xf 2.625 sc70 - 5 max823sexk xe 2.925 sc70 - 5 max823texk xc 3.075 sc70 - 5 max823wexk xl 1.665 sc70 - 5 max823yexk xk 2.188 sc70 - 5 max823zexk xj 2.315 sc70 - 5
micrel, inc. max823/4/5 january 14, 2014 3 revision 1.0 ordering information (continued) ( 1 ) part number top marking v rst : nominal threshold voltage (v) package max824leuk x4l 4.625 sot23 - 5 max824meuk x4m 4.375 sot23 - 5 max824reuk x4r 2.625 sot23 - 5 max824seuk x4s 2.925 sot23 - 5 max824teuk x4t 3.075 sot23 - 5 max824weuk x4w 1.665 sot23 - 5 max824yeuk x4y 2.188 sot23 - 5 max824zeuk x4z 2.315 sot23 - 5 max824lexk 4y 4.625 sc70 - 5 max824mexk ya 4.375 sc70 - 5 max824rexk yd 2.625 sc70 - 5 max824sexk yc 2.925 sc70 - 5 max824texk yb 3.075 sc70 - 5 max824wexk yg 1.665 sc70 - 5 max824yexk yf 2.188 sc70 - 5 max824zexk ye 2.315 sc70 - 5 part number top marking v rst : nominal threshold voltage (v) package max825leuk x5l 4.625 sot23 - 5 max825meuk x5m 4.375 sot23 - 5 max825reuk x5r 2.625 sot23 - 5 max825seuk x5s 2.925 sot23 - 5 max825teuk x5t 3.075 sot23 - 5 max825weuk x5w 1.665 sot23 - 5 max825yeuk x5y 2.188 sot23 - 5 max 825z euk x5z 2.315 sot23 - 5 max825lexk ye 4.625 sc70 - 5 max825mexk yi 4.375 sc70 - 5 max825rexk yo 2.625 sc70 - 5 max825sexk yk 2.925 sc70 - 5 max825texk yj 3.075 sc70 - 5 max825wexk yt 1.665 sc70 - 5 max825yexk ys 2.188 sc70 - 5 max825zexk yr 2.315 sc70 - 5 note: 1. all devices are available in tape - and - reel only. contact micrel for tape - and - reel options.
micrel, inc. max823/4/5 january 14, 2014 4 revision 1.0 pin configuration max823 sot23(euk) &sc70(exk ) top view max 824 sot23(euk) &sc70(exk ) top view max 825 sot23(euk) &sc70(exk ) top view pin description pin number max823 pin number max824 pin number max825 pin name pin function 1 1 1 /reset active - low reset output. pulses low for 200ms when triggered, and remains low whenever v cc is below the reset threshold or when /mr is a logic low. it remains low for 200ms after one of the following occurs: v cc rises above the reset threshold, the watchdog triggers a reset, or /m r goes low to high. 2 2 2 gnd ground. - 3 3 reset active - high reset output. pulses high for 200ms when triggered, and remains high whenever v cc is below the reset threshold or when /mr is a logic low. it remains high for 200ms after one of the following occurs: v cc rises above the reset threshold, the watchdog triggers a reset, or /mr goes low to high. reset is the inverse of /reset. 4 4 - wdi watchdog input. if wdi remains either high or low for longer than the watchdog timeout period, the internal watchdog timer runs out and a reset is triggered. the internal watchdog timer clears whenever reset is asserted, or whenever wdi sees a rising or fa lling edge. if wdi is left unconnected or is connected to a three - stated buffer output, the watchdog feature is disabled. 3 - 4 /mr manual reset input. a logic low on /mr asserts reset. reset remains asserted as long as /mr is held low and for 200ms after /mr returns high. the active - low input has an internal 52k pull - up resistor. it can be driven from a cmos logic line or shorted to ground with a switch. leave open or connect to vcc if unused. 5 5 5 vcc supply voltage pin. vcc is the input to the supply v oltage monitor. when the supply voltage falls below the reset threshold voltage, reset outputs (/reset and reset) are triggered immediately. when the supply voltage rises above the reset threshold plus hysteresis voltage, the reset outputs remain asserte d for the duration of the reset timeout period. an optional 0.1 f bypass capacitor mounted close to vcc provides additional transient immunity.
micrel, inc. max823/4/5 january 14, 2014 5 revision 1.0 absolute maximum ratings ( 2 ) supply voltage (v cc ) ................................ .... ? 0.3v to ? 6.0v /mr, wdi, reset, /reset .................. ? 0.3v to v cc +0.3v input current (all pins except reset, /reset) ........ 20ma output current (reset, /reset) .............................. 20ma junc tion temperature (t j ) ........................ ? 40c to +150 c storage temperature (t s ) ......................... ? 65 c to +150 c esd rating ( 4 ) (human body model)(max823/4/5) ........ 3 kv operating ratings ( 3 ) supply voltage (v cc ) ................................ .... +1. 0v to +5.5 v watchdog input (wdi) ................................ ........... 0v to v cc junction temperature (t j ) ........................ C 40c to +12 5c junction thermal resistance 5 - pin sot23 ................................ .................... 215 c/w 5 - pin sc70 ................................ ...................... 250 c/w electrical characteristics ( 5 ) v cc = 4.7v to 5.5v for max823/4/5l, v cc = 4.5v to 5.5v for max823/4/5m, v cc = 3.15v to 3.6v for max823/4/5t, v cc = 3.0v to 3.6v for max823/4/5s, v cc = 2.7v to 3.6v for max823/4/5r, v cc = 2. 38v to 2.75v for max823/4/5z, v cc = 2.25v to 2.75v for max823/4/5y, v cc = 1.75v to 2.0v for max823/4/5w; t j = +25?c, bold values ( 6 ) indicate C 40?c t j +125?c, unless otherwise noted. parameter condition min . typ . max . units power suppy input supply voltage (v cc ) 1.0 5.5 v supply current (i vcc ) l/m (wdi and /mr unconnected) 4.8 14 a t/s/r/z/y/w (wdi and /mr unconnected) 3.8 8.4 a reset threshold voltage reset threshold voltage (v rst ) l (falling) t a = 25 ? ? ? ? a ? ? 4.556 4.694 v m (falling) t a = 25 ? C ? ? a ? ? 4.309 4.441 v t (falling) t a = 25 ? C ? ? a ? ? 3.029 3.121 v s (falling) t a = 25 ? C ? ? a ? ? 2.881 2.969 v r (falling) t a = 25 ? C ? ? a ? ? 2.586 2.664 v z (falling) t a = 25 ? C ? ? a ? ? 2.280 2.350 v y (falling) t a = 25 ? C ? ? a ? ? 2.155 2.221 v w (falling) t a = 25 ? C ? ? a ? ? 1.640 1.690 v reset threshold hysteresis l, m 10 mv t, s, r, z, y, w 5 mv reset threshold tempco 40 ppm/ ?
micrel, inc. max823/4/5 january 14, 2014 6 revision 1.0 electrical characteristics ( continued ) ( 5 ) v cc = 4.7v to 5.5v for max823/4/5l, v cc = 4.5v to 5.5v for max823/4/5m, v cc = 3.15v to 3.6v for max823/4/5t, v cc = 3.0v to 3.6v for max823/4/5s, v cc = 2.7v to 3.6v for max823/4/5r, v cc = 2.3 8v to 2.75v for max823/4/5z, v cc = 2.25v to 2.75v for max823/4/5y, v cc = 1.75v to 2.0v for max823/4/5w; t j = +25?c, bold values ( 6 ) indicate C 40?c t j +125?c, unless otherwise noted. parameter condition min . typ . max . units reset timeout period (t rp ) 140 200 280 ms reset time vcc to /reset delay (t rd ) 10 s reset outputs (/reset, reset) /reset output voltage high (v oh ) l, m: v cc ?? rst (max) , i source = 120 a v cc C 1.5 v t, s, r, z, y: v cc ?? rst (max) , i source = 30 a 0.8 v cc v w: v cc ?? rst (max) , i source = 20 a 0.8 v cc v /reset output voltage low (v ol ) l, m: v cc ?? rst (min) , i sink = 3.2ma 0.4 v t, s, r, z, y, w: v cc ?? rst (min) , i sink = 1.2ma 0.3 v t a = 0 ? ? cc = 1v, i sink =50 a 0.3 v v cc = 1.2v, i sink =100 a 0.3 v /reset output short - circuit current ( 7 ) l, m: /reset = 0v, v cc = 5.5v 800 a t, s, r, z, y, w: /reset = 0v, v cc = 3.6v 400 a reset output voltage high (v oh ) v cc ?? ?? source = 150 a 0.8 v cc v reset output voltage low (v ol ) l, m: v cc ?? rst (max) , i sink = 3.2ma 0.4 v t, s, r, z, y, w: v cc ?? rst (max) , i sink = 1.2ma 0.3 v watchdog input (wdi) ( 8 ) watchdog timeout period (t wd ) 1.12 1.60 2.40 s watchdog pulse width 50 ns watchdog input low voltage (v il ) 0.3 v cc v watchdog input high voltage (v ih ) 0.7 v cc v watchdog input current wdi = v cc 15 25 a wdi = 0v - 20 - 15 a
micrel, inc. max823/4/5 january 14, 2014 7 revision 1.0 electrical characteristics ( continued ) ( 5 ) v cc = 4.7v to 5.5v for max823/4/5l, v cc = 4.5v to 5.5v for max823/4/5m, v cc = 3.15v to 3.6v for max823/4/5t, v cc = 3.0v to 3.6v for max823/4/5s, v cc = 2.7v to 3.6v for max823/4/5r, v cc = 2.3 8v to 2.75v for max823/4/5z, v cc = 2.25v to 2.75v for max823/4/5y, v cc = 1.75v to 2.0v for max823/4/5w; t j = +25?c, bold values ( 6 ) indicate C 40?c t j +125?c, unless otherwise noted. parameter condition min . typ . max . units manual reset input (/mr) input low voltage (v il ) 0.3 v cc v input high voltage (v ih ) 0.7 v cc v /mr pulse width 1.0 s /mr noise immunity (pulse width with no reset) 100 ns /mr to reset delay 500 ns /mr internal pull - up resistor 35 52 75 k ? notes: 2. exceeding the absolute maximum ratings may damage the device. 3. the device is not guaranteed to function outside its operating ratings. 4. devices are esd sensitive. handling precautions are recommended. human body model, 1.5k ? in series with 100pf. 5. specification for packaged product only . 6. overtemperature limits are guaranteed by design and not product tested. 7. the /reset short - circuit current is the maximum pull - up current when /reset is drive n low by p bidirectional reset pin. 8. the wdi input is designed to drive a three - state output device with a 10 a maximum leakage current and a maximum capacitance of 200pf.
micrel, inc. max823/4/5 january 14, 2014 8 revision 1.0 typical characteristics 0 1 2 3 4 5 6 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 supply current (a) input voltage (v) supply current vs. input voltage max823w max824l max825s /mr = open wdi = open 0 1 2 3 4 5 6 7 -40 -20 0 20 40 60 80 100 120 supply current (a) temperature ( c) supply current vs. temperature max824l, v cc = 5.5v max823w, v cc = 2v max825s, v cc = 3.25v /mr = open wdi = open 0 50 100 150 200 250 -40 -20 0 20 40 60 80 100 120 reset timeout period (ms) temperature ( c) reset timeout period vs. temperature /mr = open wdi = open 0 100 200 300 400 500 600 700 800 -40 -20 0 20 40 60 80 100 120 140 /mr to reset delay (ns) temperature ( c) /mr to reset delay vs. temperature 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 2 -40 -20 0 20 40 60 80 100 120 watchdog timeout period (s) temperature ( c) watchdog timeout period vs. temperature 0.92 0.94 0.96 0.98 1 1.02 1.04 1.06 -40 -20 0 20 40 60 80 100 120 reset threshold voltage (v) temperature ( c) normalized reset threshold vs. temperature
micrel, inc. max823/4/5 january 14, 2014 9 revision 1.0 functional diagram timing diagram
micrel, inc. max823/4/5 january 14, 2014 10 revision 1.0 functional description design and product advantages the max823/4/5 is series of a voltage supervisor reset ic with a manual reset input, watchdog input , and dual reset outputs. the max 823 /4/5 asserts and holds a reset when the supply voltage falls below the factory - programmed threshold voltage, when /mr is at low logic level , or when watchdog input times out. reset is asserted for a fixed reset timeout period after the supply voltage increases above the rising threshold voltage or when the manual reset input is asserted high. the max823/4/5 features an active - low, push - pull reset output (/reset) and an active - high, push - pull reset output (reset). it also contains 52k pull - up resistors on the /mr input to make it easy to connect to pushbutton inputs. the max823/4 also feature s a watchdog input (wdi) . manual reset input (/mr) the /mr input pin has integrated pull - up resistors to keep the current consumption l ow when the push button switch is pressed . reset outputs (/reset and reset) there are two reset outputs: /reset and reset . b oth outputs are push - pull , which eliminates the n eed for pull - up resistors. the reset output is the inverse of the /reset output. asserting /reset and reset outputs when functioning as a manual reset the reset outputs /reset and reset are asserted while the /mr pin is driven low. both reset outputs remai n asserted for a factory - programmed reset timeout delay time , t rp . the typical value of a reset timeout period is 200ms. the /reset pin is driven low while the reset pin is driven high whenever /mr is pulled low. figure 1 . manual reset function when functioning as a voltage supervisor the /reset pin is asserted whenever v cc falls below the reset threshold voltage, v rst (v cc < v rst ). the vcc pin circuitry includes hysteresis to prevent /reset or reset pin chattering due to noise. the /reset pin remains asserted for the duration of the reset timeout delay (t rp ) after v cc has risen above the reset threshold voltage plus the hysteresis. the reset function ensures that a microprocessor is properly reset and powers up in a known condition after a power failure. the /reset remains valid with v cc as low as 1v. the reset output is a comple ment of the /reset output. figure 2 . voltage supervisor function
micrel, inc. max823/4/5 january 14, 2014 11 revision 1.0 watchdog input the max823/4 has an on - chip watch dog t imer that can reset the microprocessor if it fails to strobe the wdi input within a preset timeout period (t wd ). if the wdi pin is left unconnected, this function is disabled. the watchdog timeout period starts when the reset outputs are deasserted or eith er a high - to - low or low - to - high transition occurs before the watchdog timeout period (t wd ). if the watchdog timer times out , then the reset outputs will assert and stay asserted for a reset timeout period (t rp ). the watchdog timer is also cleared whenever the reset out put s are asserted by /mr , or if v cc falls below v rst . t he watchdog timer starts again whenever the reset out put s are de - asserted. figure 3 . watchdog input watchdog input current the wdi input current is the current sourced or sinked by the wdi pin when the wdi input is driven low or high , respectively. the wdi input is designed to drive a t ri - state output device with a 10 a maximum leakage current and a maximum capacitance of 200p f. v cc transient the max823/4/5 is relatively immune to small negative - going v cc glitches below the res et threshold. as shown in figure 4 , the overdrive voltage is the difference between the threshold voltage and the minimum point of the v cc glitch. typically, an overdrive of 100mv with duration of 2 s or less will not cause a reset. figure 4 . vcc transient reset valid up to v cc = 1v the max823/4/5 is a supervisory circuit that monitors the power supply voltage level . i f the power supply voltage level falls below the factory - programmed threshold level , then the reset signals are asserted. the max823/4/5 maintains the reset states with v cc as low as 1v. supply bypass capacitor an optional 0.1 f input bypass capacitor can be placed from vcc (pin 6) to gnd (pin 2) to increase glitch rejection and pro vides additional transient immunity.
micrel, inc. max823/4/5 january 14, 2014 12 revision 1.0 typical application s figure 5 . max825 for precision power good function figure 6 . max823 used for load switch figure 7 . max824 used for microcontroller reset with watchdog input
micrel, inc. max823/4/5 january 14, 2014 13 revision 1.0 package information ( 9 ) 5 - pin sot23 (euk)
micrel, inc. max823/4/5 january 14, 2014 14 revision 1.0 package information (continued) ( 9 ) 5 - pin sc70 (exk) note: 9. package information is correct as of the publication date. for updates and the most current information, go to www.micrel.com . micrel, inc. 2180 fortune drive san jose, ca 95131 usa tel +1 (408) 944 - 0800 fax +1 (408) 474 - 1000 web http://www.micrel.com micrel makes no representations or warranties with respect to the accuracy or completeness of the information furnished in th is data sheet. this information is not intended as a warranty and micrel does not a ssume responsibility for its use. micrel reserves the right to change circuitry, specifications and descriptions at any time without notice. no license, whether express, implied, arising by estoppel or otherwise, to any intellectual property rights is gr anted by this document. except as provided in micrels terms and conditions of sale for such products, micrel assumes no liability purchasers use or sale of micrel products for use in life support appliances, devices or systems is a purchasers own risk a ? 20 1 4 micrel, incorporated.

▲Up To Search▲

Price & Availability of MAX823REXK

	To Download MAX823REXK Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .