for free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800 _______________general description the max809/MAX810 are microprocessor (?) supervi- sory circuits used to monitor the power supplies in ? and digital systems. they provide excellent circuit reli- ability and low cost by eliminating external components and adjustments when used with 5v-powered or 3v- 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 for at least 140ms after v cc has risen above the reset threshold. the only difference between the two devices is that the max809 has an active-low reset output (which is guar- anteed to be in the correct state for v cc down to 1v), while the MAX810 has an active-high reset output. the reset comparator is designed to ignore fast tran- sients on v cc . reset thresholds suitable for operation with a variety of supply voltages are available. low supply current makes the max809/MAX810 ideal for use in portable equipment. the max809/MAX810 come in a 3-pin sot23 package. ________________________applications computers controllers intelligent instruments critical ? and ? power monitoring portable/battery-powered equipment automotive ____________________________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 (max809) reset output (MAX810) ? 17? supply current ? guaranteed reset valid to v cc = 1v (max809) ? power supply transient immunity ? no external components ? 3-pin sot23 package ______________ordering information max809j/l/m/r/s/t, MAX810l/m/r/s/t 3-pin microprocessor reset circuit ________________________________________________________________ maxim integrated products 1 top view (reset) reset 1 gnd v cc max809
MAX810 sot23 2 3 ( ) are for MAX810 max809 v cc v cc reset reset
input gnd v cc gnd m p __________________pin configuration __________typical operating circuit part ? max809_eur-t -40? to +105? temp. range pin-package 3 sot23-3 MAX810_eur-t -40? to +105? 3 sot23-3 suffix l m j* reset threshold (v) 4.00 4.38 4.63 s r 2.63 2.93 19-0344; rev 2; 2/96 t 3.08 ordering information continued at end of data sheet. ? insert the desired suffix letter (from the table below) into the blank to complete the part number: * j version is available for max809 only.
max809j/l/m/r/s/t, MAX810l/m/r/s/t 3-pin microprocessor reset circuit 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v cc = full range, t a = -40? to +105?, unless otherwise noted. typical values are at t a = +25?, v cc = 5v for l/m/j versions, v cc = 3.3v for t/s versions, and v cc = 3v for r version.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. terminal voltage (with respect to gnd) v cc ........................................................................-0.3v to 6.0v reset, reset ..........................................-0.3v to (v cc + 0.3v) input current, v cc ..............................................................20ma output current, reset, reset ..........................................20ma rate of rise, v cc....................................................................... 100v/? continuous power dissipation (t a = +70?) sot23 (derate above +70? by 4mw/?) ...................320mw operating temperature range .........................-40? to +105? storage temperature range .............................-65? to +160? lead temperature (soldering, 10sec) .............................+300? v cc = v th to (v th - 100mv) conditions ? 20 v cc to reset delay (note 2) 3.04 3.11 4.25 4.50 4.56 4.63 4.70 4.50 4.75 4.40 4.86 4.31 4.38 4.45 units min typ max symbol parameter max8_ _l max8_ _m v th reset threshold (note 2) max809j v 3.00 3.08 3.15 4.16 4.56 3.93 4.00 4.06 3.89 4.10 3.80 4.20 t a = +25? t a = -40? to +85? t a = +85? to +105? t a = +25? t a = -40? to +85? t a = +85? to +105? t a = +25? t a = -40? to +85? t a = +85? to +105? t a = +25? v cc = v th min, i sink = 1.2ma, max809r/s/t 0.3 v cc = v th min, i sink = 3.2ma, max809l/m 0.4 v cc > 1.0v, i sink = 50? v 0.3 v ol reset output voltage low (max809) t a = -40? to +105? 1.2 5.5 t a = 0? to +70? v 1.0 5.5 v cc range t a = -40? to +85? ? 17 50 i cc supply current 24 60 ppm/? 30 reset threshold tempco 2.92 3.23 t a = -40? to +85? t a = +85? to +105? t a = +85? to +105? 100 100 v cc < 5.5v, max8_ _ l/m t a = -40? to +85? t a = +85? to +105? 100 840 reset active timeout period ms 140 240 560 max8_ _s t a = +25? t a = -40? to +85? t a = +85? to +105? t a = +25? t a = -40? to +85? t a = +85? to +105? max8_ _r 2.50 2.76 2.55 2.70 2.89 2.93 2.96 2.85 3.00 2.78 3.08 2.59 2.63 2.66 max8_ _t v cc < 5.5v, max8_ _ l/m v cc < 3.6v, max8_ _ r/s/t v cc < 3.6v, max8_ _ r/s/t
max809j/l/m/r/s/t, MAX810l/m/r/s/t 3-pin microprocessor reset circuit _______________________________________________________________________________________ 3 35 0 -40 85 supply current vs. temperature
(no load, max8_ _r/s/t) 20 25 30 max809/10-toc1 temperature (?) supply current (?) 20 10 5 -20 0 60 15 40 v cc = 5v v cc = 3v v cc = 1v 0 supply current vs. temperature
(no load, max8_ _l/m) 20 25 30 max809/10-toc2 temperature (?) supply current (?) 10 5 15 -40 85 20 -20 0 60 40 v cc = 5v v cc = 3v v cc = 1v 0 power-down reset delay vs. temperature
(max8_ _r/s/t) 80 100 max809/10-toc3 temperature (?) power-down reset delay ( m s) 40 20 60 -40 85 20 -20 0 60 40 v od = v th - v cc v od = 20mv v od = 10mv v od = 200mv v od = 100mv 0 power-down reset delay vs. temperature
(max8_ _l/m) 80 100 120 140 max809/10-toc4 temperature (?) power-down reset delay ( m s) 40 20 60 -40 85 20 -20 0 60 40 v od = v th - v cc v od = 10mv v od = 100mv v od = 200mv v od = 20mv 225 power-up reset timeout
vs. temperature 245 250 max809/10-toc5 temperature (?) power-up reset timeout (ms) 235 230 240 -40 85 20 -20 0 60 40 max8_ _r/s/t max8_ _l/m 0.997 normalized reset threshold
vs. temperature 1.001 1.002 1.003 max809/10-toc6 temperature (?) normalized threshold 0.999 0.998 1.000 -40 85 20 -20 0 60 40 __________________________________________typical operating characteristics electrical characteristics (continued) (v cc = full range, t a = -40? to +105?, unless otherwise noted. typical values are at t a = +25?, v cc = 5v for l/m/j versions, v cc = 3.3v for t/s versions, and v cc = 3v for r version.) (note 1) note 1: production testing done at t a = +25?, over temperature limits guaranteed by design only. note 2: reset output for max809, reset output for MAX810. v cc = v th max, i sink = 1.2ma, MAX810r/s/t v cc > v th max, i source = 500?, max809r/s/t conditions v v cc - 1.5 v oh reset output voltage high (max809) v v 0.8v cc v oh reset output voltage high (MAX810) 0.4 v cc > v th max, i source = 800?, max809l/m v ol reset output voltage low (MAX810) v cc = v th max, i sink = 3.2ma, MAX810l/m 0.3 0.8v cc 1.8v < v cc < v th min, i source = 150? units min typ max symbol parameter
max809j/l/m/r/s/t, MAX810l/m/r/s/t __________applications information negative-going v cc transients in addition to issuing a reset to the microprocessor (?) during power-up, power-down, and brownout condi- tions, the max809/MAX810 are relatively immune to short duration negative-going v cc transients (glitches). figure 1 shows typical transient duration vs. reset com- parator overdrive, for which the max809/MAX810 do not generate a reset pulse. the graph was generated using a negative-going pulse applied to v cc , starting 0.5v above the actual reset threshold and ending below it by the magnitude indicated (reset comparator overdrive). the graph indicates the maximum pulse width a negative-going v cc transient can have without causing a reset pulse. as the magnitude of the tran- sient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. typically, for the max809l and MAX810m, a v cc tran- sient that goes 100mv below the reset threshold and lasts 20? or less will not cause a reset pulse. a 0.1? bypass capacitor mounted as close as possible to the v cc pin provides additional transient immunity. ensuring a valid reset output down to v cc = 0v when v cc falls below 1v, the max809 reset output no longer sinks current?t becomes an open circuit. therefore, high-impedance cmos logic inputs con- nected to reset can drift to undetermined voltages. this presents no problem in most applications, since most ? and other circuitry is inoperative with v cc below 1v. however, in applications where reset must be valid down to 0v, adding a pull-down resistor to reset causes any stray leakage currents to flow to ground, holding reset low (figure 2). r1? value is not critical; 100k is large enough not to load reset and small enough to pull reset to ground. a 100k pull-up resistor to v cc is also recommended for the MAX810, if reset is required to remain valid for v cc < 1v. 3-pin microprocessor reset circuit 4 _______________________________________________________________________________________ 2 reset (max809) reset output remains low while v cc is below the reset threshold, and for 240ms after v cc rises above the reset threshold. 1 gnd ground pin name function reset (MAX810) reset output remains high while v cc is below the reset threshold, and for 240ms after v cc rises above the reset threshold. _____________________pin description 400 320 0 1 100 1000 160 80 240 reset comparator overdrive , v th - v cc (mv) maximum transient duration (?) 10 t a = +25? max8_ _l/m max8_ _r/s/t figure 1. maximum transient duration without causing a reset pulse vs. reset comparator overdrive 3 v cc supply voltage (+5v, +3.3v, or +3.0v)
interfacing to ?s with bidirectional reset pins ?s with bidirectional reset pins (such as the motorola 68hc11 series) can connect to the max809 reset out- put. if, for example, the max809 reset output is asserted high and the ? wants to pull it low, indetermi- nate logic levels may result. to correct this, connect a 4.7k resistor between the max809 reset output and the ? reset i/o (figure 3). buffer the max809 reset output to other system components. benefits of highly accurate reset threshold most ? supervisor ics have reset threshold voltages between 5% and 10% below the value of nominal sup- ply voltages. this ensures a reset will not occur within 5% of the nominal supply, but will occur when the sup- ply is 10% below nominal. when using ics rated at only the nominal supply ?%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the reset may or may not be asserted. the max809l/t and MAX810l/t use highly accurate circuitry to ensure that reset is asserted close to the 5% limit, and long before the supply has declined to 10% below nominal. max809j/l/m/r/s/t, MAX810l/m/r/s/t 3-pin microprocessor reset circuit _______________________________________________________________________________________ 5 r1
100k v cc gnd max809 reset figure 2. reset valid to v cc = ground circuit 4.7k v cc gnd reset max809 reset v cc gnd m p buffer buffered reset
to other system
components figure 3. interfacing to ?s with bidirectional reset i/o transistor count: 275 ___________________chip information
max809j/l/m/r/s/t, MAX810l/m/r/s/t 3-pin microprocessor reset circuit 6 _______________________________________________________________________________________ ___________________________________________ordering information (continued) 4.0?.1 4.0?.1 2.0?.05 1.75?.1 ?.5?.1 ?.1?.1 8.0?.2 3.5?.05 aa = max809l
ab = max809m
cw = max809j
ac = max809t
ad = max809s
af = max809r
ag = MAX810l
ah = MAX810m
aj = MAX810t
ak = MAX810s
al = MAX810r
x x x x lot specific
code marking
information note: dimensions are in mm.
and follow eia481-1 standard. ics may also be marked with full part name: 809l, 809m? ? ?
max809j/l/m/r/s/t, MAX810l/m/r/s/t 3-pin microprocessor reset circuit _______________________________________________________________________________________ 7 ________________________________________________________package information l dim
a
a1
b
c
d
e
e
h
l
s
a min
0.031
0.001
0.014
0.0034
0.105
0.047
0.070
0.082
0.004
0.017
0? max
0.047
0.005
0.022
0.006
0.120
0.055
0.080
0.098
0.012
0.022
8? min
0.787
0.025
0.356
0.086
2.667
1.194
1.778
2.083
0.102
0.432
0? max
1.194
0.127
0.559
0.152
3.048
1.397
2.032
2.489
0.305
0.559
8? inches millimeters a 3-pin sot23-3
small-outline
transistor package d e a a1 c b s 21-0051b h e
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 8 ___________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 (408) 737-7600 1996 maxim integrated products printed usa is a registered trademark of maxim integrated products. max809j/l/m/r/s/t, MAX810l/m/r/s/t 3-pin microprocessor reset circuit
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