max709 power-supply monitor with reset ________________________________________________________________ maxim integrated products 1 n.c. n.c. reset v cc n.c. gnd n.c. n.c. 1 2 3 4 87 6 5 dip/so/ max max709 __________________pin configuration top view reset gnd gnd v cc v cc p max709 reset __________typical operating circuit call toll free 1-800-998-8800 for free samples or literature. 19-0136; rev. 2; 12/05 _______________general description the max709 provides a system reset during power-up,power-down, and brownout conditions. when v cc falls below the reset threshold, reset goes low and holds the ? in reset for 140ms min after v cc rises above the threshold. the reset output is guaranteed to be in the correct state with v cc down to 1v. the max709 provides excellent circuit reliability and low cost by eliminatingexternal components and adjustments when used with +5v, +3.3v, or +3v powered systems. the max709 is available 8-pin dip, ?ax, and so packages. _______________________applications minimum component count, low-cost processor systems ___________________________features ? +5v, +3.3v, and +3v versions ? no external components ? low cost ? precise power-down reset threshold ? 140ms min power-on reset delay ? immune to short negative v cc transients ? 8-pin dip, max, and so packages ? low supply current: 35a - max709r/s/t 65a - max709l/m ______________ordering information part temp. range pin-package max709_cpa 0? to +70? max709_csa 0? to +70? 8 so max709_c/d 0? to +70? dice max709_epa -40? to +85? 8 plastic dip max709_esa -40? to +85? 8 so 8 plastic dip devices are available in both leaded and lead-free packaging.specify lead free by adding the + symbol at the end of the part number when ordering. * dice are specified at t a = +25 ? ,dc parameters only. note: this part offers a choice of five different reset thresholdvoltages. select the letter corresponding to the desired nominal reset threshold voltage, and insert it into the blank to complete the part number. reset threshold suffix voltage (v) l 4.65 m 4.40 t 3.08 s 2.93 r 2.63 max709_cua 0? to +70? 8 ?ax max709_eua -40? to +85? 8 ?ax downloaded from: http:///
max709 power-supply monitor with reset 2 _______________________________________________________________________________________ terminal voltage (with respect to gnd) v cc ................................................ -0.3v to 6.0v reset .................................... -0.3v to (v cc + 0.3v) input current, v cc .......................................... 20ma output current, reset ..................................... 20ma rate-of-rise, v cc ......................................... 100v/? continuous power dissipation (t a = +70?) plastic dip (derate 9.09mw/? above +70?) ........ 727mw ?ax (derate 4.10mw/? above +70?) ............. 330mw so (derate 5.88mw/? above +70?) ................. 471mw operating temperature ranges max709_c___ ...................................0 c to +70 c max709_e___ . ................................-40 c to +85 c storage temperature range ..................-65 c to +160? lead temperature (soldering, 10sec) .................... +300? electrical characteristics(v cc = full range, t a = t min to t max , unless otherwise noted.) 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. note 1: supply current is measured with v cc = 3.6v for max709r/s/t, and v cc = 5.5v for all versions. parameter conditions min typ max units v cc range 1.0 5.5 v 1.2 5.5 supply current (note 1) 35 85 ? 35 110 all versions 65 150 65 200 reset threshold, v th max709l 4.50 4.65 4.75 v max709m 4.25 4.40 4.50 max709t 3.00 3.08 3.15 max709s 2.85 2.93 3.00 max709r 2.55 2.63 2.70 v cc to reset delay v cc = reset threshold max to reset threshold min 20 ? reset active timeout period v cc = reset threshold max, v cc rising 140 280 560 ms reset output voltage 0.3 v 0.4 i sink = 50?, v cc 1.0v, max709_c 0.3 i sink = 100?, v cc 1.2v, max709_e 0.4 i source = 800?, v cc reset threshold max, max709l/m only max709_c max709_e max709_c, v cc < 3.6v max709_e, v cc < 3.6v max709_c, v cc < 5.5v max709_e, v cc < 5.5v max709r/s/t only i sink = 1.2ma, v cc = reset threshold min, max709r/s/t only i sink = 3.2ma, v cc = reset threshold min, max709l/m only i source = 500?, v cc reset threshold max, max709r/s/t only 0.8 x v cc v cc - 1.5 absolute maximum ratings downloaded from: http:///
max709 power-supply monitor with reset _________________________________________________________________________________________________ 3 300 0 -60 100 power-up reset delay vs. temperature 50 250 temperature (?) power-up reset delay (ms) 60 150100 -20 20 200 v cc = reset threshold max, v cc rising 100 20 -60 -20 60 100 supply current vs. temperature 40 80 temperature (?) supply current ( a) 20 60 0 note: steady-state supply current is independent of reset output status no load v cc = +5v v cc = +4v v cc = +3v v cc = +2v v cc = +1v 24 0 -60 100 power-down reset delay vs. temperature 4 20 temperature (?) power-down reset delay ( s) 60 12 8 -20 20 16 v cc stepped from reset threshold max to reset threshold min __________________________________________typical operating characteristics 1.0050.997 -60 -20 60 100 normalized reset threshold vs. temperature 0.999 1.003 temperature (?) normalized reset threshold 20 1.001 0.995 the reset threshold is shown normalized to 1, representing all available max709 reset thresholds downloaded from: http:///
max709 power-supply monitor with reset 4 _______________________________________________________________________________________ __________applications information negative-going v cc transients in addition to issuing a reset to the microprocessor(?) during power-up, power-down, and brownout con- ditions, the max709 is relatively immune to short dura- tion negative-going v cc transients (glitches). figure 1 shows typical transient duration vs. reset com-parator overdrive, for which the max709 does not gen- erate a reset pulse. the graph was generated using a negative-going pulse applied to v cc , starting 1.5v above the actual reset threshold and ending below itby the magnitude indicated (reset comparator over- drive). the graph indicates the typical maximum pulse width that a negative-going v cc transient may have without causing a reset pulse to be issued. as themagnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. typically, for the max709l/max709m, a v cc transient that goes 100mv below the reset threshold and lasts 40? or less will notcause a reset pulse to be issued. a 0.1? bypass capacitor mounted as close as possibleto pin 2 (v cc ) provides additional transient immunity. ensuring a valid reset output down to v cc = 0v when v cc falls below 1v, the max709 reset output no longer sinks current?t becomes an open circuit. therefore, high-impedance cmos logic inputs con- nected to the reset output can drift to undermined voltages. this presents no problem in most applica- tions, since most ? and other circuitry is inoperative with v cc below 1v. however, in applications where the reset output must be valid down to 0v, adding a pull- down resistor to the reset pin will cause any stray leakage currents to flow to ground, holding reset low (see figure 2). the resistance value of r1 is not criti- cal. it should be about 100k ? , which is large enough not to load reset and small enough to pull reset to ground. ____________________pin description pin name function n.c. no connect. there is no internal connection to this pin. 2 v cc +5v, +3.3v, or +3v supply voltage 3 gnd ground 7 reset 1, 4, 5, 6, 8 reset output remains low while v cc is below the reset threshold, and for280ms after v cc rises above the reset threshold. 150 0 10 100 10k 50 100 reset comparator overdrive, v th - v cc (mv) maximum transient duration ( s) 1k max709l/m max709r/s/t t a = +25? 10ns figure 1. maximum transient duration without causing a reset pulse vs. reset comparator overdrive downloaded from: http:///
max709 power-supply monitor with reset _______________________________________________________________________________________ 5 interfacing to ps with bidirectional reset pins microprocessors with bidirectional reset pins (such asthe motorola 68hc11 series) can contend with the max709 reset output. if, for example the max709 reset output is asserted high and the ? wants to pull it low, indeterminate logic levels may result. to correct this, connect a 4.7k ? resistor between the max709 reset output and the ? reset i/o (see figure 3). buffer the max709 reset output to other system com- ponents. r1 v cc gnd max709 reset figure 2. reset valid to v cc = ground circuit 4.7k v cc gnd reset max709 v cc gnd p buffer buffered resetto other system components reset figure 3. interfacing to ?s with bidirectional reset i/o downloaded from: http:///
max709 power-supply monitor with reset 6 _______________________________________________________________________________________ minimum nominal nominal reset watchdog power- reset pulse timeout backup- c c e e - fail manual- watch- low- active- battery- part threshold width period battery write com- reset dog line high on number (v) (ms) (sec) switch protect parator input output output reset output max690a/692a 4.65/4.40 140 1.6 ?? max691a/693a 4.65/4.40 140/adj. 1.6/adj. ?? /10ns ?? ? ? ? max696 adj. 35/adj. 1.6/adj. ??? ? ?? max697 adj. 35/adj. 1.6/adj. ?? ?? ? max700 4.65/adj. 200 - ?? max703/704 4.65/4.40 140 - ?? ? max705/706 4.65/4.40 140 1.6 ??? max706p 2.63 140 1.6 ??? ? max706r/s/t 2.63/2.93/ 140 1.6 ??? 3.08 max707/708 4.65/4.40 140 - ?? ? max708r/s/t 2.63/2.93/ 140 - ?? ? 3.08 max709l/m/ 4.65/4.40/ 140 - r/s/t 2.63/2.93/3.08 max791 4.65 140 1 ?? /10ns ? ??? ?? max792l/m/ 4.65/4.40/ 140 1 ? /10ns ? ??? ? r/s/t 2.63/2.93/3.08 max800l/m 4.60/4.40 140 1.6/adj. ?? /10ns ? /2% ?? ?? max802l/m 4.60/4.40 140 1.6 ?? /2% max805l 4.65 140 1.6 ?? ? max813l 4.65 140 1.6 ??? ? max820l/m/ 4.65/4.40/ 140 1 ? /10ns ? /2% ??? ? r/s/t 2.63/2.93/3.08 max1232 4.37/4.62 250 0.15/0.60/1.2 ? max1259 - - - ?? _____________________________________________________p supervisory circuits downloaded from: http:///
max709 power-supply monitor with reset _______________________________________________________________________________________ 7 reset v cc gnd 0.045" (1.143mm) 0.056" (1.422mm) ___________________chip topography transistor count: 380substrate connected to v cc downloaded from: http:///
maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it 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 2005 maxim integrated products printed usa is a registered trademark of maxim integrated products, inc. max709 power-supply monitor with reset 8lumaxd.eps package outline, 8l umax/usop 1 1 21-0036 j rev. document control no. approval proprietary information title: max 0.0430.006 0.014 0.120 0.120 0.198 0.026 0.007 0.037 0.0207 bsc 0.0256 bsc a2 a1 c e b a l front view side view e h 0.60.1 0.60.1 ?0.500.1 1 top view d 8 a2 0.030 bottom view 1 6 s b l h e d e c 0 0.0100.116 0.116 0.188 0.016 0.005 8 4x s inches - a1 a min 0.002 0.95 0.75 0.5250 bsc 0.25 0.36 2.95 3.05 2.95 3.05 4.78 0.41 0.65 bsc 5.030.66 6 0 0.13 0.18 max min millimeters - 1.10 0.05 0.15 dim package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline information, go to www.maxim-ic.com/packages .) downloaded from: http:///
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