________________ general description maxim? max8211 and max8212 are cmos micropowervoltage detectors that warn microprocessors (?s) of power failures. each contains a comparator, a 1.5v bandgap reference, and an open-drain n-channel output driver. two external resistors are used in conjunction with the internal reference to set the trip voltage to the desired level. a hysteresis output is also included, allowing the user to apply positive feedback for noise-free output switching. the max8211 provides a 7ma current-limited output sink whenever the voltage applied to the threshold pin is less than the 1.5v internal reference. in the max8212, a voltage greater than 1.5v at the threshold pin turns the output stage on (no current limit). the cmos max8211/max8212 are plug-in replacements for the bipolar icl8211/icl8212 in applications where the maximum supply voltage is less than 16.5v. they offer sev- eral performance advantages, including reduced supply current, a more tightly controlled bandgap reference, and more available current from the hysteresis output. ________________________applications ? voltage monitoringundervoltage detection overvoltage detection battery-backup switching power-supply fault monitoring low-battery detection ____________________________features ? p power-fail warning ? improved 2nd source for icl8211/icl8212 ? low-power cmos design ? 5 a quiescent current ? on-board hysteresis output ? 40mv threshold accuracy (3.5%) ? 2.0v to 16.5v supply-voltage range ? define output current limit (max8211) ? high output current capability (max8212) _______________or dering information max8211/max8212 microprocessor voltage monitors with programmable voltage detection ___________________________________________________ _____________ maxim integrated products 1 v+ hystthresh max8211 out gnd v+ r3 r2 r1 logic-supply undervoltage detector (detailed circuit diagram?igure 5) p nmi _________________ pin configurations top view v+ max8211max8212 n.c. n.c.gnd 8 76 5 23 4 n.c. 1 hyst thresh out dip/so ___________t ypical operating circuit 19-0539; rev 5; 9/08 ordering information continued on last page. * contact factory for dice specifications. ** contact factory for availability and processing to mil-std-883. for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. pin configurations continued at end of data sheet. part temp range pin - pa c k a g e max8211 cpa -0? to +70? 8 plastic dip max8211csa -0? to +70? 8 so max8211cua -0? to +70? 8 ?ax max8211cty -0? to +70? 8 to-99 max8211epa -40? to +85? 8 plastic dip max8211esa -40? to +85? 8 so max8211eja -40? to +85? 8 cerdip max8211ety -40? to +85? 8 to-99 max8211mja -55? to +125? 8 cerdip** downloaded from: http:///
max8211/max8212 microprocessor voltage monitors with programmable voltage detection 2 __________________________________________________ _____________________________________ supply voltage .......................................................-0.5v to +18v output voltage .......................................................-0.5v to +18v hysteresis...................+0.5v to -18v with respect to (v+ + 0.5v) threshold input voltage ...............................-0.5v to (v+ + 0.5v) current into any terminal .................................................?0ma continuous power dissipation (t a = +70?) 8-pin plastic dip (derate 9.09mw/? above +70?) .....727mw 8-pin so (derate 5.88mw/? above +70?)..................471mw 8-pin cerdip (derate 8.00mw/? above +70?)..........640mw 8-pin to-99 (derate 6.67mw/? above +70?).............533mw operating temperature ranges max821_c_ _ .......................................................0? to +70? max821_e_ _.....................................................-40? to +85? max821_m_ _ ..................................................-55? to +125? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? 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. absolute maximum ratings electrical characteristics (v+ = 5v, t a = +25?, unless otherwise noted.) parameter symbol conditions units t a = +25? 51 5 51 5 supply current i+ 2v v+ 16.5v, gnd v th v+ t a = t min to t max 20 20 ? threshold voltage disparity between output and hysteresis output v thp ?.1 ?.1 mv 2.0 16.5 2.0 16.5 guaranteed operatingsupply voltage range v supp 2.2 16.5 2.2 16.5 v typical operating supply voltage range v supp 1.5 16.5 1.5 16.5 v threshold voltagetemperature coefficient ? v th / ? t -200 -200 ppm/? variation of thresholdvoltage with supply voltage ? v th v+ = 4.5v to 5.5v 1.0 0.2 mv 0.01 10 0.01 10 threshold input current i th 20 20 na output leakage current i lout v out = 16.5v, v th = 1.0v 10 v out = 16.5v, v th = 1.3v 10 v out = 5v, v th = 1.0v 1 t a = t min to t max , c/e temp. ranges v out = 5v, v th = 1.3v 1 v out = 16.5v, v th = 0.9v 30 v out = 16.5v, v th = 1.3v 30 v out = 5v, v th = 0.9v 10 t a = t min to t max , m temp. range v out = 5v, v th = 1.3v 10 ? max8212 min typ max max8211 min typ max t a = t min to t max 0v v th v+, t a = +25? i out = 4ma, i hyst = 1ma t a = +25? t a = t min to t max see figure 4 v+ = 16.5v, i out = 3ma 1.05 1.25 1.05 1.25 v+ = 16.5v, i out = 4ma 1.11 1.19 1.11 1.19 threshold trip voltage v th t a = +25? v+ = 2v, i out = 500? v t a = t min to t max v+ = 2.2v, i out = 500? downloaded from: http:///
max8211/max8212 microprocessor voltage monitors with programmable voltage detection ___________________________________________________ _____________________________________ 3 note 1: the maximum output current of the max8211 is limited by design to 30ma under any operating condition. the output voltage may be sustained at any voltage up to +16.5v as long as the maximum power dissipation of the device is not exceeded. note 2: the maximum output current of the max8212 is not defined, and systems using the max8212 must therefore ensure that the output current does not exceed 50ma and that the maximum power dissipation of the device is not exceeded. electrical characteristics (continued) (v+ = 5v, t a = +25?, unless otherwise noted.) parameter symbol conditions units i out = 2ma, v th = 1.0v 0.17 0.4 output saturation voltage v ol i out = 2ma, v th = 1.3v 0.17 0.4 v v th = 1.0v (note 1) 4 7.0 maximum availableoutput current i oh c temp. range,v out = 5v v th = 1.3v (note 2) 12 35 ma t a = t min to t max , c/e temp. ranges, v+ = 16.5v, v th = 1.0v, v hyst = -16.5v with respect to v+ 0.1 0.1 hysteresis leakagecurrent i lhys t a = t min to t max , m temp. range, v+ = 16.5v, v th = 0.9v, v hyst = -16.5v with respect to v+ 3 3 ? hysteresis saturationvoltage v hys (max) i hyst = 0.5ma, v th = 1.3v, measured with respect to v+ -0.1 -0.2 -0.1 -0.2 v maximum availablehysteresis current v hys (max) v th = 1.3v, v hys = 0v 21 0 21 0 ma max8212 min typ max max8211 min typ max _______________detailed description as shown in the block diagrams of figures 1 and 2, themax8211 and max8212 each contain a 1.15v refer- ence, a comparator, an open-drain n-channel output transistor, and an open-drain p-channel hysteresis out- put. the max8211 output n-channel turns on when the voltage applied to the thresh pin is less than the internal reference (1.15v). the sink current is limited to 7ma (typical), allowing direct drive of an led without a series resistor. the max8212 output turns on when the voltage applied to thresh is greater than the internal reference. it is not current limited, and will typically sink 35ma. compatibility with icl8211/icl8212 the cmos max8211/max8212 are plug-in replacementsfor the bipolar icl8211/icl8212 in most applications. the use of cmos technology has several advantages. the quiescent supply current is much less than in the bipolar parts. higher-value resistors can also be used p n 1.15v reference hystout thresh v+ figure 1. max8211 block diagram downloaded from: http:///
max8211/max8212 microprocessor voltage monitors with programmable voltage detection 4 __________________________________________________ ______________________________________ v+ hystthresh max8211max8212 out gnd v+ r3 r2 r1 v out v in figure 3. basic overvoltage/undervoltage circuit in the networks that set up the trip voltage, since thecomparator input (thresh pin) is a low-leakage mosfet transistor. this further reduces system current drain. the tolerance of the internal reference has also been significantly improved, allowing for more precise voltage detection without the use of potentiometers. the available current from the hyst output has been increased from 21? to 10ma, making the hysteresis feature easier to use. the disparity between the hyst output and the voltage required at thresh to switch the out pin has also been reduced in the max8211 from 8mv to 0.1mv to eliminate output ?hatter?or oscillation. most voltage detection circuits operate with supplies of 15v or less; in these applications, the max8211/ max8212 will replace icl8211/icl8212s with the per- formance advantages described above. however, note that the cmos parts have an absolute maximum sup- ply-voltage rating of 18v, and should never be used in applications where this rating could be exceeded. exercise caution when replacing icl8211/icl8212s in closed-loop applications such as programmable zeners. although neither the icl8211/icl8212 nor the max8211/max8212 are internally compensated, the cmos parts have higher gain and may not be stable for the external compensation-capacitor values used in lower-gain icl8211/icl8212 circuits. __________applications information basic voltage detectors figure 3 shows the basic circuit for both undervoltagedetection (max8211) and overvoltage detection (max8212). for applications where no hysteresis is needed, r3 should be omitted. the ratio of r1 to r2 is then chosen such that, for the desired trip voltage at v in , 1.15v is applied to the thresh pin. since the com- parator inputs are very low-leakage mosfet transis-tors, the max8211/max8212 can use much higher resistors values in the attenuator network than can the bipolar icl8211/icl8212. see table 1 for switching delays. table 1. switching delays voltage detectors with hysteresis to ensure noise-free output switching, hysteresis is frequently used in voltage detectors. for both the max8211 and max8212 the hyst output is on for threshold voltages greater than 1.15v. r3 (figure 3) controls the amount of current (positive feedback) sup- plied from the hyst output to the mid-point of the resis- tor divider, and hence the magnitude of the hysteresis, or dead-band. figure 2. max8212 block diagram p n 1.15v reference hystout thresh v+ typical delays max8211 max8212 t (on) 40? 250? t (off) 1.5ms 3ms downloaded from: http:///
calculate resistor values for figure 3 as follows: 1) choose a value for r1. typical values are in the 10k ? to 10m ? range. 2) calculate r2 for the desired upper trip point v u using the formula: 3) calculate r3 for the desired amount of hysteresis, where v l is the lower trip point: or, if v+ = v in : figure 5 shows an alternate circuit, suitable only when thevoltage being detected is also the power-supply voltage for the max8211 or max8212. calculate resistor values for figure 5 as follows: 1) choose a value for r1. typical values are in the 10k ? to 10m ? range. 2) calculate r2: 3) calculate r3: low-voltage detector for logic supply the circuit of figure 5 will detect when a 5.0v (nominal)supply goes below 4.5v, which is the v min normally specified in logic systems. the selected resistor valuesensure that false undervoltage alarms will not be gener- ated, even with worst-case threshold trip values and resistor tolerances. r3 provides approximately 75mv of hysteresis. r3 r1 (v u v l ) 1.15v = r2 r1 (v l v th ) v th r1 (v l 1.15v) 1.15v = = r3 r2 (v l v th ) (v u v l ) r2 (v l 1.15v) (v u v l ) = = r3 r2 (v v th ) (v u v l ) r2 (v + 1.15v) (v u v l ) = + = r2 = r1 (v u v th ) v th r1 (v u 1.15v) 1.15v = max8211/max8212 microprocessor voltage monitors with programmable voltage detection ___________________________________________________ _____________________________________ 5 -55 t a ( c) v th (v) 1.2501.230 1.210 1.190 1.170 1.150 1.130 1.110 1.090 1.070 1.050 max8211,8212-fig 4 -25 25 75 125 v+ = 16.5v v+ = 2v figure 4. max8211/max8212 threshold trip voltage vs. ambient temperature v in hyst max8211 out gnd v+ r3 48.7k ? 1% r2 2.2m ? 1% r1 750k ? 1% v out (low forv in < 4.5v) thresh figure 5. max8211 logic-supply low-voltage detector downloaded from: http:///
max8211/max8212 microprocessor voltage monitors with programmable voltage detection 6 __________________________________________________ _____________________________________ _ordering information (continued) _____________________________________________pin configurations (continued) 12 3 4 8 76 5 threshhyst n.c. v+ gnd n.c. n.c. out max8211max8212 max top view top view 8 7 6 5 4 3 2 1 hyst v+ n.c. n.c. gnd n.c. thresh out to-99* case is connected to pin 7 on tv package. case is connected to pin 4 on ty package. * * contact factory for dice specifications. ** contact factory for availability and processing to mil-std-883. part temp range pin - pa c k a g e max8211msa/pr -55? to +125? 8 so** max8211msa/pr-t -55? to +125? 8 so** max8211mtv -55? to +125? 8 to-99** max8212 cpa -0? to +70? 8 plastic dip max8212csa -0? to +70? 8 so max8212cua -0? to +70? 8 ?ax max8212cty -0? to +70? 8 to-99 max8212epa -40? to +85? 8 plastic dip max8212esa -40? to +85? 8 so max8212eja -40? to +85? 8 cerdip max8212ety -40? to +85? 8 to-99 max8212mja -55? to +125? 8 cerdip** max8212msa/pr -55? to +125? 8 so** max8212msa/pr-t -55? to +125? 8 so** max8212mtv -55? to +125? 8 to-99** package information for the latest package outline information and land patterns, goto www.maxim-ic.com/packages . package type package code document no. 8 cerdip j8-2 21-0045 8 plastic dip p8-1 21-0043 8 so s8-2 21-0041 8 to-99 t99-8 21-0022 8 ?ax u8-1 21-0036 downloaded from: http:///
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. 7 ___________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 (408) 737-7600 2008 maxim integrated products is a registered trademark of maxim integrated products, inc. max8211/max8212 microprocessor voltage monitors with programmable voltage detection revision history revision number revision date description pages changed 0 1/91 initial release 4 9/02 updated figure 5. 5 5 9/08 updated ordering information . 1, 6 downloaded from: http:///
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