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general description the max6453Cmax6456 are low-power, dual-voltage p supervisors featuring separate v cc reset and manu- al reset outputs. the dual outputs support both soft- system reset (interrupt) and hard-system reset (reboot) functions. the reset output asserts when any of the monitored voltages falls below its specified threshold and remains asserted for the reset timeout (140ms min) after all voltages exceed their respective reset thres- holds. all devices are offered with nine factory-fixed reset thresholds for monitoring primary system voltages (v cc ) from 1.8v to 5v and an adjustable reset input for monitoring a secondary system voltage down to 0.63v. each device has a manual reset input, a v cc reset out - put, and a manual reset output. the max6453/max6454 manual reset output asserts when the manual reset input is low. it remains asserted for the manual reset timeout period (140ms min) after the manual reset input transi - tions high. the max6453/max6454 manual reset input controls only the manual reset output and does not affect the v cc reset output. the manual reset input of the max6455/max6456 con - trols both the manual reset and v cc reset outputs. when the manual reset input is low for less than the extended setup timeout period, only the manual reset output asserts and remains asserted for the manual reset timeout period (140ms min) after the manual reset input transitions high. if the manual reset input is low for at least the extended setup timeout period, the reset output also asserts and remains asserted for the reset timeout period (140ms min) after the manual reset input transitions high. this enhanced feature allows the implementation of a soft/ hard-system reset combination. the max6453/max6455 have active-low, push-pull reset and manual reset outputs, and the max6454/ max6456 have active-low, open-drain reset and manu- al reset outputs. all devices are available in small sot23-6 packages and are fully specified over the extended temperature range (-40c to +85c). applications set-top boxes consumer electronics dvd players cable/dsl modems mp3 players industrial equipment medical devices features precision factory-set reset thresholds from 1.6v to 4.6v adjustable threshold to monitor voltages down to 0.63v manual reset input with extended setup period immune to short voltage transients low 6a supply current guaranteed valid reset down to v cc = 1.0v active-low reset (push-pull or open-drain) outputs 140ms (min) reset timeout period small sot package note: the first _ _ is a placeholder for the threshold voltage level of the devices. a desired threshold level is set by the part number suffix found in table 1. the third _ is a placeholder for the manual reset setup period of the devices. a desired setup period is set by the letter suffix found in table 2. all devices are available in tape-and-reel only. there is a 2500-piece minimum order increment for standard versions (table 2). sample stock is typically held on standard versions only. nonstandard ver- sions require a minimum order increment of 10,000 pieces. contact factory for availability. devices are available in both leaded and lead(pb)-free packaging. specify lead-free by replacing -t with +t when ordering. part temp range pin-package max6453 ut_ _ _-t -40c to +85c 6 sot23 max6454 ut_ _ _-t -40c to +85c 6 sot23 max6455 ut_ _ _-t -40c to +85c 6 sot23 max6456 ut_ _ _-t -40c to +85c 6 sot23 gnd v cc mrout 1 6 mr 5 rstin reset max6453max6454 sot23-6 top view 2 3 4 gnd v cc mrout 1 6 mr 5 rstin reset max6455max6456 sot23-6 2 3 4 max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs 19-2637; rev 4; 5/14 pin conigurations selector guide appears at end of data sheet. ordering information downloaded from: http:///
(all voltages referenced to gnd) v cc ........................................................................ -0.3v to +6v open-drain reset , mrout .................................. -0.3v to +6v mr , push-pull reset , mrout .............. -0.3v to (v cc + 0.3v) mr , rstin ............................................................. -0.3v to +6v input current, all pins ...................................................... 20ma continuous power dissipation (t a = +70c) 6-pin sot23 (derate 8.7mw/c above +70c) .......... 696mw operating temperature range .......................... -40c to +85c junction temperature ...................................................... +150c storage temperature range ............................ -65c to +150c lead temperature (soldering, 10s) ................................. +300c soldering temperature (reflow) lead(pb)-free ...............................................................+260c containing lead .......................................................... +240c (v cc = 1.0v to 5.5v, t a = -40c to +85c, unless otherwise specified. typical values are at t a = +25c.) (note 1) parameter symbol conditions min typ max units operating voltage range v cc 1.0 5.5 v v cc supply current i cc v cc = 5.5v, no load 7 20 a v cc = 3.6v, no load 6 16 v cc reset threshold v th 46 4.50 4.63 4.75 v 44 4.25 4.38 4.50 31 3.00 3.08 3.15 29 2.85 2.93 3.00 26 2.55 2.63 2.70 23 2.25 2.32 2.38 22 2.12 2.19 2.25 17 1.62 1.67 1.71 16 1.52 1.58 1.62 reset threshold tempco 60 ppm/c reset threshold hysteresis 2 v th mv rstin threshold v th-rstin t a = 0c to +85c 0.615 0.630 0.645 v t a = -40c to +85c 0.610 0.650 rstin threshold hysteresis v hyst 2.5 mv rstin input current i rstin -25 +25 na rstin to reset output delay v rstin falling at 1mv/s 15 s reset timeout period t rp 140 210 280 ms v cc to reset output delay t rd v cc falling at 1mv/s 20 s mr minimum setup period (pulse width) t mr mr to reset k 6.72 10.08 13.44 s l 4.48 6.72 8.16 s 2.24 3.36 4.48 t 1.12 1.68 2.24 mr minimum input pulse reset asserted, max6455/max6456 2.24 3.36 4.48 s mr glitch rejection 100 ns mr to mrout delay 200 ns manual reset timeout period t mrp 140 210 280 ms max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 2 electrical characteristics stresses beyond those listed under absolute 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 downloaded from: http:///
note 1: devices production tested at t a = 25c. overtemperature limits are guaranteed by design. (v cc = 1.0v to 5.5v, t a = -40c to +85c, unless otherwise specified. typical values are at t a = +25c.) (note 1) parameter symbol conditions min typ max units mr to v cc pullup impedance 25 50 75 k ? reset , mrout output low (open drain or push-pull) v ol v cc 1.00v, i sink = 50a, outputs asserted 0.3 v v cc 1.20v, i sink = 100a, outputs asserted 0.3 v cc 2.55v, i sink = 1.2ma, outputs asserted 0.3 v cc 4.25v, i sink = 3.2ma, outputs asserted 0.4 reset , mrout output high (push-pull) v oh v cc 1.80v, i source = 200a, outputs deasserted 0.8 v cc v v cc 3.15v, i source = 500a, outputs deasserted 0.8 v cc v cc 4.75v, i source = 800a, outputs deasserted 0.8 v cc reset , mrout output open-drain leakage current i lkg outputs deasserted 1 a mr input low voltage v il 0.3 v cc v mr input high voltage v ih 0.7 v cc v max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 3 electrical characteristics (continued) downloaded from: http:///
(v cc = 3.3v, t a = +25c, unless otherwise noted.) v cc to reset delay max6453 toc08 time (100 s/div) v cc (100mv/div) reset (2v/div) v cc = 4.5v v th = 4.392v v cc = 4.3v manual reset to mrout and reset delay (max6455/max6456) max6453 toc07 time (1s/div) mr (5v/div) mrout (5v/div) reset (5v/div) v cc = 5v rstin to reset delay vs. temperature (rstin falling) max6453 toc06 temperature (c) rstin to reset delay ( s) 60 35 10 -15 20.4 20.8 21.2 21.6 22.0 22.4 22.8 23.2 23.6 24.020.0 -40 85 rstin falling at 1mv/ s v cc to reset delay vs. temperature max6453 toc05 temperature (c) v cc to reset delay ( s) 60 35 10 -15 20.4 20.8 21.2 21.6 22.0 22.4 22.8 23.2 23.6 24.020.0 -40 85 v cc falling at 1mv/ s normalized v cc reset threshold vs. temperature max6453 toc04 temperature (c) normalized v cc reset threshold 60 35 10 -15 0.98 0.99 1.00 1.01 1.02 1.030.97 -40 85 maximum transient duration vs. reset threshold overdrive max6453 toc03 reset threshold overdrive (mv) transient duration ( s) 800 600 400 200 50 100 150 200 250 0 0 1000 reset occursabove the curve v th = 4.4v normalized reset timeout period vs. temperature max6453 toc02 temperature (c) normalized timeout period 60 35 10 -15 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.050.95 -40 85 supply current vs. supply voltage max6453 toc01 supply voltage (v) supply current ( a) 5.0 4.5 3.5 4.0 2.0 2.5 3.0 1.5 1 2 3 4 5 6 7 8 90 1.0 5.5 t a = +85c t a = -40c t a = +25c max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs maxim integrated 4 www.maximintegrated.com typical operating characteristics downloaded from: http:///
pin name function max6453 max6454 max6455 max6456 1 reset active-low push-pull or open-drain output. reset changes from high to low when v cc or rstin drops below its selected reset threshold. reset remains low for the 140ms (min) reset timeout period after all monitored power-supply inputs exceed their selected reset thresholds. mr does not affect reset output. for open-drain outputs, connect to an external pullup resistor. 1 active-low push-pull or open-drain output. reset changes from high to low when v cc or rstin drops below its selected reset threshold. reset remains low for the 140ms (min) reset timeout period after all monitored power-supply inputs exceed their selected reset thresholds. reset changes from high to low after mr input is held low for the extended (typ) setup timeout period and deasserts 140ms (min) after mr deasserts. for open-drain outputs, connect to an external pullup resistor. 2 2 gnd ground 3 3 mrout manual reset push-pull or open-drain output. mrout asserts immediately after mr is pulled low. mrout remains low for 140ms (min) after mr is deasserted. for open- drain outputs, connect to an external pullup resistor. 4 4 v cc v cc voltage input. power supply and input for the primary microprocessor voltage reset monitor. 5 5 rstin reset input. high-impedance input to the adjustable reset comparator. connect rstin to the center point of an external resistor divider to set the threshold of the externally monitored voltage. 6 mr manual reset input. internal 50k ? pullup to v cc . pull mr low to immediately assert mrout . mr does not affect reset output. 6 manual reset input. internal 50k ? pullup to v cc . pull mr low to immediately assert mrout . reset changes from high to low after mr input is held low for the extended (typ) setup timeout period. max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 5 pin description downloaded from: http:///
detailed description reset output the reset output is typically connected to the reset input of a microprocessor (p). a ps reset input starts or restarts the p in a known state. the max6453Cmax6456 p supervisory circuits provide the reset logic to prevent code-execution errors during power-up, power-down and brownout conditions (see the typical operating circuit ). reset changes from high to low whenever the moni - tored voltage (rstin or v cc ) drops below the reset threshold voltages. when vrstin and v cc exceed their respective reset threshold voltages, reset remains low for the reset timeout period, and then goes high. reset changes from high to low after mr input is held low for the extended (typ) setup timeout period and deasserts 140ms (min) after mr deasserts. reset is guaranteed to be in the proper output logic state for v cc inputs 1v. for applications requiring valid reset logic when v cc is less than 1v, see the ensuring a valid reset output down to v cc = 0v section. manual reset the max6453/max6454 contain a manual reset output ( mrout ) that asserts low immediately after driving mr low and remains low for the reset timeout period after mr goes high (figure 1). the pushbutton manual reset has no effect on the reset output. mrout output can be used to drive an nmi (nonmaskable interrupt) on the processor to save valuable data. the max6455/max6456s mrout is asserted imme - diately upon driving mr low. driving mr low for longer than the extended (typ) setup timeout period asserts reset . when mr is deasserted, mrout and reset remain asserted low for the reset timeout period after mr goes high (figure 2). adjustable input voltage (rstin) the max6453Cmax6456 monitor the voltage on rstin using an adjustable reset threshold set with an external resistor voltage divider (figure 3). use the following formula to calculate the externally monitored voltage (v mon-th ): v mon-th = v th-rstin (r1 +r2)/r2 where v mon_th is the desired reset threshold voltage and v th-rstin is the reset input threshold (0.63v). resistors r1 and r2 can have very high values to mini - mize current consumption due to low leakage currents. set r2 to some conveniently high value (250k ? , for example) and calculate r1 based on the desired reset threshold voltage, using the following formula: r1 = r2 5 (v mon_th/vth - 1 ) ? figure 2. max6455/max6456 timing diagram figure 1. max6453/max6454 timing diagram 210ms mrout reset mr long setup period 210ms mrout mr max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 6 downloaded from: http:///
applications information interrupt before reset to minimize data loss and speed system recovery/test, many applications interrupt the processor or reset only portions of the system before a processor hard reset is asserted. the extended setup time of the max6455/ max6456 mr input allows the same pushbutton (figure 4) to control both the interrupt and hard reset functions. if the pushbutton is closed for less than the extended setup timeout period, the processor is only interrupted ( mrout ). if the system still does not respond properly, the pushbutton can be closed for the full extended setup timeout period to hard reset the processor ( reset ). if desired, connect a led to the reset out - put to turn off (or on) to signify when the pushbutton is closed long enough for a hard reset (the same led can be used as the front panel power-on display). interfacing to other voltages for logic compatibility the open-drain reset output can be used to interface to a p with other logic levels. as shown in figure 5, the open-drain output can be connected to voltages from 0 to 6v. generally, the pullup resistor connected to the reset connects to the supply voltage being monitored at the ics v cc pin. however, some systems might use the open-drain output to level-shift from the monitored supply to reset circuitry powered by some other supply (figure 5). keep in mind that as the supervisors v cc decreases toward 1v, so does the ics ability to sink current at reset ( reset is pulled high as v cc decays toward 0). the voltage where this occurs depends on the pullup resistor value and the voltage to which it is connected. ensuring a valid reset down to v cc = 0v (push-pull reset ) when v cc falls below 1v, reset current-sinking capabil - ities decline drastically. the high-impedance cmos-logic inputs connected to reset can drift to undetermined voltages. this presents no problem in most applications, because most ps and other circuitry do not operate with v cc below 1v. in applications where reset must be valid down to 0v, add a pulldown resistor between reset and gnd for the push/pull outputs. the resistor sinks any stray leak- age currents, holding reset low (figure 6). the value of the pulldown resistor is not critical; 100k ? is large enough not to load reset and small enough to pull reset to ground. the external pulldown cannot be used with the open-drain reset outputs. transient immunity in addition to issuing a reset to the p during power-up, power-down and brownout conditions, these supervisors are relatively immune to short duration falling transients (glitches). the graph maximum transient duration vs. reset threshold overdrive in the typical operating characteristics section shows this relationship. the area below the curves of the graph is the region in which these devices typically do not generate a reset pulse. this graph was generated using a negative going pulse applied to v cc , starting above the actual reset threshold (v th ) and ending below it by the magni - tude indicated (reset-threshold overdrive). as the mag- nitude of the transient increases (v cc goes further below the reset threshold), the maximum allowable pulse width decreases. typically, a v cc transient that goes 100mv below the reset threshold and lasts 20s or less does not cause a reset pulse to be issued. figure 3. calculating the monitored threshold voltages max6453max6455 rstin v cc r1 r2 reset gnd v mon_th = 0.63 x (r1 + r2) / r2 v mon_th v cc max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 7 downloaded from: http:///
figure 6. ensuring reset valid to v cc = 0 figure 5. interfacing to other voltage levels figure 4. interrupt before reset application circuit max6453Cmax6456 rstin v cc reset timout period (210ms typ) mrout timout period (210ms typ) mr -to- reset setup period (3.36s typ) max6455/max6456 0.63v 1.23v mr gnd v cc v cc resetmrout max6453max6455 reset v cc gnd v cc 100k ? max6454max6456 p reset reset gnd gnd v cc v cc 5v 3.3v 100k ? max6455 p v cc rstin reset nmi led i/o supply core supply pushbutton switchclose for immediate system interrupt close for >3.36s for system reset +3.3v+1.5v reset mrout gnd mr max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 8 functional diagram downloaded from: http:///
table 3. standard versions table table 2. manual reset setup period table 1. reset voltage threshold part mr to reset delay mr assertion mrout and reset push-pull output mrout and reset open-drain output max6453 mrout ? max6454 mrout ? max6455 ? mrout and reset ? max6456 ? mrout and reset ? part top mark part top mark max6453 ut16s abog max6455 ut16s abol max6453ut23s aboh max6455ut23s abom max6453ut26s aboi max6455ut26s abon max6453ut29s aboj max6455ut29s aboo max6453ut46s abok max6455ut46s aber max6454 ut16s abop max6456 ut16s abes max6454ut23s abeq max6456ut23s abot max6454ut26s aboq max6456ut26s abou max6454ut29s abor max6456ut29s abov max6454ut46s abos max6456ut46s abow part no. suffix ( _ ) manual reset period (s) k 10.08 l 6.72 s 3.36 t 1.68 part no. suffix ( _ _ ) v cc nominal voltage threshold (v) 46 4.625 44 4.375 31 3.075 29 2.925 26 2.625 23 2.313 22 2.188 17 1.665 16 1.575 max6453 p v cc rstin reset nmi i/o supply core supply +3.3v+1.5v reset mrout gnd mr gnd max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 9 typical operating circuit selector guide downloaded from: http:///
package type package code document no. land pattern no. 6 sot23 u6-1 21-0058 90-0175 max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs www.maximintegrated.com maxim integrated 10 package information for the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages . note that a +, #, or - in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. chip information process: bicmos downloaded from: http:///
revision number revision date description pages changed 0 10/02 initial release 3 6/10 revised the general description, features, applications, ordering information, absolute maximum ratings, electrical characteristics, pin description, the reset output, manual reset, and interrupt before reset sections, and tables 2 and 3 to add extended setup time specifications. 1, 2, 5, 6, 7, 9 4 5/14 no /v opns; removed automotive reference from applications section 1 maxim integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim integrated product. no circuit patent licenses are implied. maxim integrated reserves the right to change the circuitry and speciications without n otice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. max6453Cmax6456 p supervisors with separate v cc reset and manual reset outputs maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. ? 2014 maxim integrated products, inc. 11 revision history for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim integrateds website at www.maximintegrated.com. downloaded from: http:///

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