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general description the max6887/max6888 multivoltage supply supervi-sors provide several voltage-detector inputs, one watch- dog input, and three outputs. each voltage-detector input offers a factory-set undervoltage and overvoltage threshold. manual reset and margin disable inputs offer additional flexibility. the max6887 offers six voltage-detector inputs, while the max6888 offers four inputs. output reset asserts when any input voltage drops below its respectiveundervoltage threshold or manual reset mr is asserted. output ov asserts when any input voltage exceeds its respective overvoltage threshold. monitor standardsupply voltages listed in the selector guide . the max6887/max6888 offer a watchdog timer with aninitial and normal timeout periods of 102.4s and 1.6s, respectively. watchdog output wdo asserts when the watchdog timer expires. connect wdo to manual reset input mr to generate resets when the watchdog timer expires. reset , ov , and wdo are active-low, open- drain outputs.the max6887/max6888 are available in a 5mm x 5mm x 0.8mm, 16-pin thin qfn package and operate over the extended -40? to +85? temperature range. applications multivoltage systemstelecom networking servers/workstations/storage systems features ? hex/quad voltage detectors ? undervoltage and overvoltage thresholds ? 1% threshold accuracy ? margining disable and manual reset input ? watchdog timer ? open-drain reset , ov , and wdo outputs ? 180ms (min) reset timeout period ? few external components ? small 5mm x 5mm, 16-pin thin qfn packages max6887/max6888 hex/quad, power-supply supervisory circuits ___________________________________________________ _____________ maxim integrated products 1 part temp range pin-package max6887 _ete+ -40? to +85? 16 thin qfn-ep* max6888 _ete+ -40? to +85? 16 thin qfn-ep* ordering information selector guide 19-0291; rev 2; 2/10 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 and typical operating circuit appear at end of data sheet. note: insert the desired letter from the selector guide into the blank to complete the part number. +denotes a lead(pb)-free/rohs-compliant package. * ep = exposed pad. nominal input voltage (v)* part in1 in2 in3 in4 in5 in6 tol (%) max6887aete 5.0 3.3 2.5 1.8 adj adj 5 max6887bete 5.0 3.3 2.5 adj adj adj 5 max6887cete 5.0 3.3 1.8 adj adj adj 5 max6887dete 3.3 2.5 1.8 1.5 adj adj 5 max6887eete 3.3 2.5 1.8 adj adj adj 5 max6887fete 3.3 2.5 1.5 adj adj adj 5 max6887gete 3.3 2.5 adj adj adj adj 5 max6887hete 3.3 1.8 adj adj adj adj 5 max6887qete adj adj adj adj adj adj 5 nominal input voltage (v)* part in1 in2 in3 in4 in5 in6 tol (%) max6887iete 5.0 3.3 2.5 1.8 adj adj 10 max6887jete 5.0 3.3 2.5 adj adj adj 10 max6887kete 5.0 3.3 1.8 adj adj adj 10 max6887lete 3.3 2.5 1.8 1.5 adj adj 10 max6887mete 3.3 2.5 1.8 adj adj adj 10 max6887nete 3.3 2.5 1.5 adj adj adj 10 max6887oete 3.3 2.5 adj adj adj adj 10 max6887pete 3.3 1.8 adj adj adj adj 10 MAX6887RETE adj adj adj adj adj adj 10 * see thresholds options tables (tables 1 and 2) for actual undervoltage and overvoltage thresholds. selector guides continued at end of data sheet. downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits 2 __________________________________________________ _____________________________________ absolute maximum ratings electrical characteristics (v in1 ? in4 or v cc = 2.7v to 5.8v, wdi = gnd, margin = mr = bp, t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (notes 1, 2) 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. (all voltages referenced to gnd.)in1?n6, v cc , reset , ov , wdo .............................-0.3v to +6v wdi, mr , margin ...................................................-0.3v to +6v bp .............................................................................-0.3v to +3v input/output current (all pins)..........................................?0ma continuous power dissipation (t a = +70?) 16-pin 5mm x 5mm thin qfn (derate 20.8mw/? above +70?) ..............................1667mw maximum junction temperature .....................................+150? operating temperature range ...........................-40? to +85? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units operating voltage range(note 3) voltage on either one of in1?n4 or v cc to guarantee the part is fully operational 2.7 5.8 v supply current i cc v in1 = 5.8v, in2?n6 = gnd, no load 0.9 1.2 ma in1?n6, in_ falling, t a = +25? to +85? -1 +1 threshold accuracy(see the selector guide ) v th in1?n6, in_ falling, t a = -40? to +85? -1.5 +1.5 % v th threshold hysteresis v th-hyst 0.3 % v th threshold tempco ? v th /? 10 ppm/? in_ input impedance r in for v in_ < highest v in1 in4 and v in_ < v cc (not adj), thresholds are not set as adjustable 130 200 300 k ? in5, in6 (max6887 only) in_ input leakage current i in in1?n4 set as adjustable thresholds -150 +150 na power-up delay t d-po v cc 2.5v 2.5 ms in_ to reset or ov delay t d-r in_ falling/rising, 100mv overdrive 20 ? reset timeout period t rp 180 200 220 ms ov timeout period t op 25 ? reset , ov , and wdo output low v ol i sink = 4ma, output asserted 0.4 v reset , ov , and wdo output open-drain leakage current i lkg output high impedance -1 +1 ? downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits ___________________________________________________ ____________________________________ 3 note 1: 100% production tested at t a = +25? and t a = +85?. specifications at t a = -40? are guaranteed by design. note 2: device may be supplied from any one of in1?n4 or v cc . note 3: the internal supply voltage, measured at v cc , equals the maximum of in1?n4. note 4: versions q and r require that power be applied through v cc . electrical characteristics (continued) (v in1 ? in4 or v cc = 2.7v to 5.8v, wdi = gnd, margin = mr = bp, t a = -40? to +85?, unless otherwise noted. typical values are at t a = +25?.) (notes 1, 2) parameter symbol conditions min typ max units v il 0.6 mr, margin , wdi input voltage v ih 1.4 v mr input pulse width t mr 1 s mr glitch rejection 100 ns mr to reset or ov delay t d- mr 200 ns mr to internal bp pullup current i mr v mr = 1.4v 5 10 15 a margin to internal bp pullup current i margin v margin = 1.4v 5 10 15 a wdi pulldown current i wdi v wdi = 0.6v 5 10 15 a wdi input pulse width 50 ns t wdi initial 92.16 102.4 112.64 watchdog timeout period t wd normal 1.44 1.6 1.76 s typical operating characteristics (v in1 ? in4 or v cc = 5v, wdi = gnd, margin = mr = bp, t a = +25?, unless otherwise noted.) in1?in4 supply current vs. in1?in4 supply voltage max6887 toc01 supply voltage (v) supply current (ma) 5.6 4.6 3.6 0.75 0.80 0.85 0.90 0.95 1.000.70 2.6 t a = +85 c t a = +25 c t a = -40 c v cc supply current vs. v cc supply voltage max6887 toc02 supply voltage (v) supply current (ma) 5.6 4.6 3.6 0.75 0.80 0.85 0.90 0.95 1.000.70 2.6 t a = +85 c t a = +25 c t a = -40 c timeout period (ms) 185 190 195 200 210205 215 220180 reset timeout period vs. temperature max6887 toc03 temperature ( c) 60 35 10 -15 -40 85 downloaded from: http:///
propagation delay ( s) 1.25 1.50 1.75 2.00 2.502.25 2.75 3.001.00 mr to reset output propagation delay vs. temperature max6887 toc09 temperature ( c) 60 35 10 -15 -40 85 max6887/max6888 hex/quad, power-supply supervisory circuits 4 __________________________________________________ _____________________________________ propagation delay ( s) 21 22 23 24 25 26 27 28 29 3020 in_ to reset or ov propagation delay vs. temperature max6887 toc04 temperature ( c) 60 35 10 -15 -40 85 100mv overdrive timeout period (s) 1.525 1.550 1.575 1.600 1.6501.625 1.675 1.7001.500 watchdog timeout period vs. temperature max6887 toc05 temperature ( c) 60 35 10 -15 -40 85 normalized in_ threshold 0.9980.997 0.996 0.999 1.000 1.001 1.0031.002 1.004 1.0050.995 normalized in_ threshold vs. temperature max6887 toc06 temperature ( c) 60 35 10 -15 -40 85 100 10 1 1000 maximum in_ transient vs. in_threshold overdrive max6887 toc07 in_ threshold overdrive (mv) maximum transient duration ( s) 25 50 75 100 125 150 175 200 0 po_ assertion occursabove this line output-voltage low vs. sink current max8667 toc08 sink current (ma) output-voltage low (mv) 8 6 24 50 100 150 200 300250 350 400 0 01 0 1 2 1 4 pin description pin max6887 max6888 name function 11 reset open-drain, active-low reset output. reset asserts when any input voltage falls below its undervoltage threshold or when mr is pulled low. reset remains low for 200ms after all assertion-causing conditions are cleared. an external pullup resister is required. 22 wdo open-drain, active-low watchdog timer output. logic output for the watchdog timer function.wdo goes low when wdi is not strobed high-to-low or low-to-high within the watchdog timeout period. 33 ov open-drain active-low overvoltage output. ov asserts when any input voltage exceeds its overvoltage threshold. ov remains low for 25? after all overvoltage conditions are cleared. an external pullup resistor is required. 4 4 gnd ground typical operating characteristics (continued) (v in1 ? in4 or v cc = 5v, wdi = gnd, margin = mr = bp, t a = +25?, unless otherwise noted.) downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits ___________________________________________________ ____________________________________ 5 pin description (continued) pin max6887 max6888 name function 55 mr manual reset input. pull mr low to assert reset . connect mr to wdo to generate resets when the watchdog timer expires. leave mr unconnected or connect to dbp if unused. mr is internally pulled up to bp through a 10? current source. 66 margin margin input. when margin is pulled low, reset is held in its existing state independent of subsequent changes in monitored input voltages or the watchdog timer expiration. margin is internally pulled up to bp through a 10? current source. leave margin unconnected or connect to bp if unused. margin overrides mr if both are asserted at the same time. 7 7 wdi watchdog timer input. logic input for the watchdog timer function. if wdi is not strobed with avalid low-to-high or high-to-low transition within the selected watchdog timeout period, wdo asserts. wdi is internally pulled down to gnd through a 10? current sink. 8 8 i.c. internal connection. leave unconnected. 99v cc internal power-supply voltage. bypass v cc to gnd with a 1? ceramic capacitor as close to the device as possible. v cc supplies power to the internal circuitry. v cc is internally powered from the highest of the monitored in1?n4 voltages. do not use v cc to supply power to external circuitry. to externally supply v cc , see the powering the max6887/max6888 section. 10 10 bp bypass voltage. the internally generated voltage at bp supplies power to internal logic andoutput reset . connect a 1? capacitor from bp to gnd as close to the device as possible. do not use bp to supply power to external circuitry. 11 in6 input voltage detector 6. in6 monitors both undervoltage and overvoltage conditions. see thethresholds options (tables 1 and 2) for available thresholds. in6 cannot power the device. for improved noise immunity, bypass in6 to gnd with a 0.1? capacitor installed as close to the device as possible. 12 in5 input voltage detector 5. in5 monitors both undervoltage and overvoltage conditions. see thethresholds options (tables 1 and 2) for available thresholds. in5 cannot power the device. for improved noise immunity, bypass in5 to gnd with a 0.1? capacitor installed as close to the device as possible. 13 13 in4 input voltage detector 4. in4 monitors both undervoltage and overvoltage conditions. see thethresholds options (tables 1 and 2) for available thresholds. power the device through in1?n4 or v cc (see the powering the max6887/max6888 section). for improved noise immunity, bypass in4 to gnd with a 0.1? capacitor installed as close to the device as possible. 14 14 in3 input voltage detector 3. in3 monitors both undervoltage and overvoltage conditions. see thethresholds options (tables 1 and 2) for available thresholds. power the device through in1?n4 or v cc (see the powering the max6887/max6888 section). for improved noise immunity, bypass in3 to gnd with a 0.1? capacitor installed as close to the device as possible. 15 15 in2 input voltage detector 2. in2 monitors both undervoltage and overvoltage conditions. see thethresholds options (tables 1 and 2) for available thresholds. power the device through in1?n4 or v cc (see the powering the max6887/max6888 section). for improved noise immunity, bypass in2 to gnd with a 0.1? capacitor installed as close to the device as possible. 16 16 in1 input voltage detector 1. in1 monitors both undervoltage and overvoltage conditions. see thethresholds options (tables 1 and 2) for available thresholds. power the device through in1?n4 or v cc (see the powering the max6887/max6888 section). for improved noise immunity, bypass in1 to gnd with a 0.1? capacitor installed as close to the device as possible. 11, 12 n.c. no connection. not internally connected. e p exposed paddle. internally connected to gnd. connect ep to gnd or leave unconnected. downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits 6 __________________________________________________ _____________________________________ functional diagram logic array (virtual diodes) wdi in2 detectorin3 detector in4 detector in5 detector in6 detector in2in3 in4 in5 (n.c.) in6 (n.c.) in1 *in_detector 1 f 1 f gnd ( ) max6888 only 2.55v ldo bp v cc mr margin max6887max6888 *for adjustable inputs refer to the adjustable threshold inputs section. reference reset wdo ov ov timing block reset timing block wdo timing block downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits ___________________________________________________ ____________________________________ 7 detailed description the max6887/max6888 provide several supply-detectorinputs, one watchdog input, and three outputs for power- supply monitoring applications. the max6887 offers six voltage-detector inputs, while the max6888 offers four. each voltage-detector input offers both an undervoltage and overvoltage threshold. the undervoltage and overvoltage thresholds are facto- ry-set for monitoring standard supply voltages (see the selector guide ). inputs in the selector guide that con- tain ?dj?allow an external voltage-divider to be con-nected to set a user-defined threshold. reset goes low when any input voltage drops below its undervoltage threshold or when mr is brought low. reset stays low for 200ms after all assertion-causing conditions have been cleared. ov goes low when an input voltage rises above its overvoltage threshold. ov typically stays low for 25? (typ) after all inputs fallback under their overvoltage thresholds. the max6887/max6888 offer a watchdog timer with initial and normal timeout periods of 102.4s and 1.6s, respectively. wdo goes low when the watchdog timer expires and deasserts when wdi transitions from low-to-high or high-to-low. powering the max6887/max6888 the max6887/max6888 derive power from the voltage-detector inputs in1?n4 or through an externally sup- plied v cc . a virtual diode-oring scheme selects the positive input that supplies power to the device (seethe functional diagram ). the highest input voltage on in1?n4 supplies power to the device. one of in1?n4must be at least 2.7v to ensure proper operation. internal hysteresis ensures that the supply input that initially powered the device continues to power the device when multiple input voltages are within 50mv of each other. v cc powers the analog circuitry and is the bypass con- nection for the max6887/max6888 internal supply.bypass v cc to gnd with a 1? ceramic capacitor installed as close to the device as possible. the inter-nal supply voltage, measured at v cc , equals the maxi- mum of in1?n4. if v cc is externally supplied, v cc must be at least 200mv higher than any voltageapplied to in1?n4 and v cc must be brought up first. v cc always powers the device when all in_ are factory set as ?dj.?do not use the internally generated v cc to provide power to external circuitry. the max6887/max6888 generate a supply voltage atbp for the internal logic circuitry. bypass bp to gnd with a 1? ceramic capacitor installed as close to the device as possible. the nominal bp output voltage is +2.55v. do not use bp to provide power to external circuitry. inputs the max6887 offers six voltage-detector inputs, whilethe max6888 offers four voltage-detector inputs. each voltage-detector input offers an undervoltage and over- voltage threshold set at the factory to monitor standard supply voltages (see the selector guide ). the 5% and 10% tolerances are based on maximum and minimumthreshold values. actual thresholds for the max6887/max6888 are shown in tables 1 and 2. inputs in the selector guide listing ?dj?allow an exter- nal voltage-divider to be connected to set a user-defined threshold. adjustable threshold inputs inputs listed in the selector guide containing ?dj?for inputs allow external resistor voltage-dividers to beconnected at the voltage-detector inputs. these inputs monitor any voltage supply higher than 0.6v (see figure 1). use the following equation to set a voltage- max6887max6888 v in in_ r1r2 *v refuv *v refov and v refuv are referenced to 0.6v according to the device's tolerance *v refov figure 1. adjusting the monitored threshold downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits 8 __________________________________________________ _____________________________________ detector input (in1?n6) to monitor a user-defined sup-ply voltage: where v mon is the desired voltage to be monitored. use the following procedure to design the proper volt-age-divider and calculate thresholds: 1) pick a value for r2. use the equation above with the desired supply voltage to be monitored andsolve for r1. use high-value resistors r1 and r2 to minimize current consumption due to low leakage currents. 2) to find the actual undervoltage and overvoltage thresholds, use the following equations: v refuv and v refov are the undervoltage and overvolt- age thresholds listed in tables 1 and 2 that allowadjustable thresholds. their values are based on toler- ances of ?.5% and ?2.5% from a 0.6v reference. see the selector guide to find which thresholds in tables 1 and 2 are adjustable. manual reset ( mr ) many ?-based products require manual reset capabilityto allow an operator or external logic circuitry to initiate a reset. the manual reset input ( mr ) can be connected directly to a switch without an external pullup resistor ordebouncing network. mr is internally pulled up to bp. leave unconnected if not used. mr is internally pulled up to bp through a 10? current source. mr is designed to reject fast, falling transients (typically 100ns pulses)and mr must be held low for a minimum of 1? to assert reset . connect a 0.1? capacitor from mr to ground to provide additional noise immunity. after mr transitions from low to high, reset remains asserted for the dura- tion of its time delay. margin output disable ( margin ) margin allows system-level testing while power sup- plies exceed the normal operating ranges. drive margin low to hold reset , ov , and wdo in their vv v v vv v v actualuv mon refuv actualov mon refov = ? ? ? ? ? ? = ? ? ? ? ? ? 06 06 . . 06 2 12 .v v r rr mon = + ? ? ? ? ? ? table 1. max6887 threshold options uv thresholds (v) ov thresholds (v) part in1 in2 in3 in4 in5 in6 in1 in2 in3 in4 in5 in6 max6887aete 4.620 3.060 2.310 1.670 0.557 0.557 5.360 3.540 2.680 1.930 0.643 0.643 max6887bete 4.620 3.060 2.310 0.557 0.557 0.557 5.360 3.540 2.680 0.643 0.643 0.643 max6887cete 4.620 3.060 1.670 0.557 0.557 0.557 5.360 3.540 1.930 0.643 0.643 0.643 max6887dete 3.060 2.310 1.670 1.390 0.557 0.557 3.540 2.680 1.930 1.610 0.643 0.643 max6887eete 3.060 2.310 1.670 0.557 0.557 0.557 3.540 2.680 1.930 0.643 0.643 0.643 max6887fete 3.060 2.310 1.390 0.557 0.557 0.557 3.540 2.680 1.610 0.643 0.643 0.643 max6887gete 3.060 2.310 0.557 0.557 0.557 0.557 3.540 2.680 0.643 0.643 0.643 0.643 max6887hete 3.060 1.670 0.557 0.557 0.557 0.557 3.540 1.930 0.643 0.643 0.643 0.643 max6887qete 0.557 0.557 0.557 0.557 0.557 0.557 0.643 0.643 0.643 0.643 0.643 0.643 max6887iete 4.380 2.880 2.190 1.580 0.527 0.527 5.620 3.700 2.810 2.020 0.673 0.673 max6887jete 4.380 2.880 2.190 0.527 0.557 0.557 5.620 3.700 2.810 0.673 0.673 0.673 max6887kete 4.380 2.880 1.580 0.527 0.557 0.557 5.620 3.700 2.020 0.673 0.673 0.673 max6887lete 2.880 2.190 1.580 1.310 0.557 0.557 3.700 2.810 2.020 1.680 0.673 0.673 max6887mete 2.880 2.190 1.580 0.527 0.557 0.557 3.700 2.810 2.020 0.673 0.673 0.673 max6887nete 2.880 2.190 1.310 0.527 0.557 0.557 3.700 2.810 1.680 0.673 0.673 0.673 max6887oete 2.880 2.190 0.527 0.527 0.557 0.557 3.700 2.810 0.673 0.673 0.673 0.673 max6887pete 2.880 1.580 0.527 0.527 0.557 0.557 3.700 2.020 0.673 0.673 0.673 0.673 MAX6887RETE 0.527 0.527 0.527 0.527 0.527 0.527 0.673 0.673 0.673 0.673 0.673 0.673 downloaded from: http:///
existing state while system-level testing occurs. leavemargin unconnected or connect to bp if unused. an internal 10? current source pulls margin to bp. margin overrides mr if both are asserted at the same time. the state of reset , ov , and wdo does not change while margin = gnd. reset , ov , and wdo outputs the max6887/max6888 feature three active-low open-drain outputs: reset , ov , and wdo . after power-up or overvoltage/undervoltage conditions, reset and ov remain in their active states until their timeout periodsexpire and no undervoltage/overvoltage conditions are present (see figure 2). ov asserts when any monitored input is above its over- voltage threshold and remains asserted until all inputsare below their thresholds and its respective 25? time- out period expires. connect ov to mr to bring reset low during an overvoltage condition. ov requires a pullup resistor (unless connected to mr ). reset asserts when any monitored input is below its undervoltage threshold or mr is asserted. reset remains asserted for 200ms after all assertion-causingconditions have been cleared. configure reset to assert when the watchdog timer expires by connectingwdo to mr . reset requires a pullup resistor. wdo asserts when the watchdog timer expires. see the configuring the watchdog timer section for a com- plete description. wdo requires a pullup resistor. configuring the watchdog timer a watchdog timer monitors microprocessor (?) soft-ware execution for a stalled condition and resets the ? if it stalls. connect the watchdog timer output wdo to the reset input or a nonmaskable interrupt of the ?.the watchdog timer features independent initial and normal watchdog timeout periods of 102.4s and 1.6s, respectively. max6887/max6888 hex/quad, power-supply supervisory circuits ___________________________________________________ ____________________________________ 9 table 2. max6888 threshold options uv thresholds (v) ov thresholds (v) part in1 in2 in3 in4 in1 in2 in3 in4 max6888aete 4.620 3.060 2.310 1.670 5.360 3.540 2.680 1.930 max6888bete 4.620 3.060 2.310 0.557 5.360 3.540 2.680 0.643 max6888cete 4.620 3.060 1.670 0.557 5.360 3.540 1.930 0.643 max6888dete 3.060 2.310 1.670 1.390 3.540 2.680 1.930 1.610 max6888eete 3.060 2.310 1.670 0.557 3.540 2.680 1.930 0.643 max6888fete 3.060 2.310 1.390 0.557 3.540 2.680 1.610 0.643 max6888gete 3.060 2.310 0.557 0.557 3.540 2.680 0.643 0.643 max6888hete 3.060 1.670 0.557 0.557 3.540 1.930 0.643 0.643 max6888qete 0.557 0.557 0.557 0.557 0.643 0.643 0.643 0.643 max6888iete 4.380 2.880 2.190 1.580 5.620 3.700 2.810 2.020 max6888jete 4.380 2.880 2.190 0.527 5.620 3.700 2.810 0.673 max6888kete 4.380 2.880 1.580 0.527 5.620 3.700 2.020 0.673 max6888lete 2.880 2.190 1.580 1.310 3.700 2.810 2.020 1.680 max6888mete 2.880 2.190 1.580 0.527 3.700 2.810 2.020 0.673 max6888nete 2.880 2.190 1.310 0.527 3.700 2.810 1.680 0.673 max6888oete 2.880 2.190 0.527 0.527 3.700 2.810 0.673 0.673 max6888pete 2.880 1.580 0.527 0.527 3.700 2.020 0.673 0.673 max6888rete 0.527 0.527 0.527 0.527 0.673 0.673 0.673 0.673 downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits 10 _________________________________________________ _____________________________________ overvoltage threshold primary threshold ov reset v in t op t rp figure 2. output timing diagram wdo wdi *t wdi is the initial watchdog timer period t rp *t wdi *t wdi t wd t d-po reset v cc or in1?n4 wdo not connected to mr 2.5v wdo wdi . t rp *t wdi t wd t rp *t dwi t d-po reset v cc or in1?n4 wdo connected to mr 2.5v figure 3. watchdog, reset, and power-up timing diagram downloaded from: http:///
at power-up, wdo goes high after t d-po (see figure 3). the initial watchdog timeout period (t wdi ) applies imme- diately after wdo is high. the initial watchdog timeout period allows the ? to perform its initialization process.a normal watchdog timeout period (t wd ) applies when- ever wdi transitions from high to low after the initialwatchdog timeout period occurs. wdi monitors the tog- gling output of the ?, indicating normal processor behavior. if wdi does not toggle during the normal watchdog timeout period (t wd ), indicating that the processor has stopped operating or is stuck in an infiniteexecution loop, wdo goes low. wdo stays low until the next transition on wdi. an initial watchdog timeout peri-od (t wdi ) starts when wdo goes high. if wdo is connected to mr, the wdo will assert for a short duration (~5?), long enough to assert the reset output. asserting reset clears the watchdog timer and wdo goes high. the reset output will remain asserted for its timeout period after a watchdog fault. the watch-dog timer stays cleared as long as reset is low. applications information layout and bypassing for better noise immunity, bypass each of the voltage-detector inputs to gnd with 0.1? capacitors installed as close to the device as possible. bypass v cc and bp to gnd with 1? capacitors installed as close to thedevice as possible. v cc (when not externally supplied) and bp are internally generated voltages and shouldnot be used to supply power to external circuitry. max6887/max6888 hex/quad, power-supply supervisory circuits ___________________________________________________ ___________________________________ 11 selector guide (continued) nominal input voltage (v)* part in1 in2 in3 in4 tolerance (%) max6888aete 5.0 3.3 2.5 1.8 5 max6888bete 5.0 3.3 2.5 adj 5 max6888cete 5.0 3.3 1.8 adj 5 max6888dete 3.3 2.5 1.8 1.5 5 max6888eete 3.3 2.5 1.8 adj 5 max6888fete 3.3 2.5 1.5 adj 5 max6888gete 3.3 2.5 adj adj 5 max6888hete 3.3 1.8 adj adj 5 max6888qete adj adj adj adj 5 max6888iete 5.0 3.3 2.5 1.8 10 max6888jete 5.0 3.3 2.5 adj 10 max6888kete 5.0 3.3 1.8 adj 10 max6888lete 3.3 2.5 1.8 1.5 10 max6888mete 3.3 2.5 1.8 adj 10 max6888nete 3.3 2.5 1.5 adj 10 max6888oete 3.3 2.5 adj adj 10 max6888pete 3.3 1.8 adj adj 10 max6888rete adj adj adj adj 10 * see thresholds options tables (tables 1 and 2) for actual under- voltage and overvoltage thresholds. chip information process: bicmos package information for the latest package outline information and land patterns, goto www.maxim-ic.com/packages . note that a "+", "#", or "-" in the package code indicates rohs status only. package draw-ings may show a different suffix character, but the drawing per- tains to the package regardless of rohs status. package type package code document no. 16-tqfn-ep t1655+2 21-0140 downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits 12 _________________________________________________ _____________________________________ margin v cc wdi wdo ov logic output logic input logic input gnd v cc gnd *max6887 only p dc-dc 1 bp dc-dc 2 dc-dc 3 dc-dc 4 in1 in2 in3 in4 1.5v in5* in6* 12v mr reset reset 12v5v 3.3v 2.5v 1.8v max6887max6888 1.2v typical operating circuit pin configurations 16 1234 12 11 10 9 15 14 13 5 6 7 8 in1 in2 in3 in4 in5in6 bp v cc wdo ov gnd mr margin wdi i.c. reset top view max6887 *exposed pad thin qfn *exposed pad connected to gnd. 16 1234 12 11 10 9 15 14 13 5 6 7 8 in1 in2 in3 in4 n.c.n.c. bp v cc wdo ov gnd mr margin wdi i.c. reset max6888 *exposed pad thin qfn *exposed pad connected to gnd. downloaded from: http:///
max6887/max6888 hex/quad, power-supply supervisory circuits 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. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 13 2010 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 0 5/05 initial release 1 3/07 revised pin description. 1, 5, 14 2 1/10 revised ordering information to add lead-free information and revised table 2. 1, 9 downloaded from: http:///

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