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max6457?ax6460 19-2048; rev 6; 12/12 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maximintegrated.com. high-voltage, low-current voltage monitors in sot packages general description the max6457?ax6460 high supply voltage, low-power voltage monitors operate over a 4v to 28v supply voltage range. each device includes a precision bandgap refer- ence, one or two low-offset voltage comparators, internal threshold hysteresis, power-good or reset timeout options, and one or two high-voltage open-drain outputs. two external resistors (three for window detection) set the trip threshold voltages. the max6457 is a single voltage monitor for undervoltage or overvoltage detection. a logic-based clear input either latches the output for overvoltage applications or allows the device to operate in transparent mode. the max6458 includes two comparators (one overvoltage and one undervoltage) for window detection and a single output to indicate if the monitored input is within an adjustable volt- age window. the max6459 includes dual overvoltage/ undervoltage comparators with two independent com- parator outputs. use the max6459 as a window com- parator with separate undervoltage and overvoltage outputs or as two independent, single voltage monitors. the max6460 includes a single comparator and an inter- nal reference, and can also accept an external reference. the inverting and noninverting inputs of the comparator are externally accessible to support positive or negative voltage monitors and to configure the device for active- high or active-low output logic. the max6457/max6458 offer fixed timing options as a voltage detector with a 50? typical delay or as a reset cir- cuit with a 90ms minimum reset timeout delay. the moni- tored input must be above the adjusted trip threshold (or within the adjusted voltage window for the max6458) for the selected timeout period before the output changes state. the max6459/max6460 offer only a fixed 50? timeout period. internal threshold hysteresis options (0.5%, 5%, and 8.3% for the max6457/max6458/max6459, and 0.5% for the max6460) reduce output chatter in noise- sensitive applications. each device is available in a small sot23 package and specified over the extended temper- ature range of -40? to +125?. applications undervoltage monitoring/shutdown overvoltage monitoring/protection window voltage detection circuitry multicell battery-stack powered equipment notebooks, ebooks automotive industrial telecom networking features wide supply voltage range, 4v to 28v internal 2.25v ?.5% reference low current (3.5 a, typ at 12v) open-drain n-channel output (28v compliant) internal threshold hysteresis options (0.5%, 5%, 8.3%) two in-to-out timeout period options (50 s, 150ms) internal undervoltage lockout immune to short voltage transients small sot23 packages few external components fully specified from -40? to +125? ordering information 5-cell li+ battery stack battery charger dc-dc converter load r1 r2 r pullup shdn +21v (nominal) v cc gnd clear in+ out max6457 in out typical operating circuit pin configurations appear at end of data sheet. part temp range pin-package max6457 ukd_ _-t -40? to +125? 5 sot23 max6458 ukd_ _-t -40? to +125? 5 sot23 max6459 ut_-t -40? to +125? 6 sot23 max6459ut_/v+ -40? to +125? 5 sot23 max6460 ut-t -40? to +125? 6 sot23 note: the max6457/max6458/max6459 are available with factory-trimmed internal hysteresis options. the max6457 and max6458 offer two fixed timing options. select the desired hys- teresis and timing options using table 1 or the selector guide at the end of the data sheet, and enter the corresponding letters and numbers in the part number by replacing ? _?or ?? these devices are offered in tape-and-reel only and must be ordered in 2500-piece increments. devices are available in both leaded and lead(pb)-free/rohs- compliant packaging. specify lead(pb)-free by replacing ?t with ?t?when ordering. /v denotes an automotive qualified part.
max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 2 maxim integrated absolute maximum ratings electrical characteristics (v cc = 4v to 28v, t a = -40? to +125?, unless otherwise specified. typical values are at t a = +25?.) (note 1) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. v cc , out, outa, outb, clear to gnd ..........-0.3v to +30.0v in+, in- to gnd..........................................-0.3v to (v cc + 0.3v) ref to gnd..............-0.3v to the lower of +6v and (v cc + 0.3v) input currents (v cc , in+, in-) ............................................20ma sink current (out, outa, outb) ......................................20ma continuous power dissipation (t a = +70?) 5-pin sot23 (derate 7.1 mw/? above +70?)............571mw 6-pin sot23 (derate 8.7 mw/? above +70?)............696mw junction temperature ......................................................+150? operating temperature range .........................-40? to +125? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) lead(pb)-free................................................................+260? containing lead (pb) .....................................................+240? parameter symbol conditions min typ max units operating voltage range v cc (note 2) 4 28 v v cc = 5v, no load 2 5 v cc = 12v, no load 3.5 7.5 supply current i cc v cc = 24v, no load 6.5 12.5 ? t a = -40? to +85?, v cc 4v 1.195 1.228 1.255 v th+ v in rising t a = +85? to +125?, v cc 4v 1.170 1.255 t a = -40? to +85? 1.180 1.255 max645_u_d_a t a = +85? to +125? 1.155 1.255 t a = -40? to +85? 1.133 1.194 max645_u_d_b t a = +85? to +125? 1.111 1.194 t a = -40? to +85? 1.093 1.151 threshold voltage v th- v in falling max645_u_d_c t a = +85? to +125? 1.071 1.151 v max64_ _u_d_a 0.5 max64_ _u_d_b 5 threshold voltage hysteresis max64_ _u_d_c 8.3 %v th+ in operating voltage range v in (note 2) 0 v cc v in leakage current i in v in = 1.25v, v cc = +28v -55 +55 na max645_ukd0_ max6459ut_ max6460ut 50 ? out timeout period t tp max6457 and max6458 only, d3 option 90 150 210 ms startup time v cc rising from gnd to v cc 4v in less than 1? (note 3) 2ms v il 0.4 clear input logic voltage (max6457) v ih 2 v max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 3 maxim integrated note 1: devices are production tested at t a = +25?. overtemperature limits are guaranteed by design. note 2: in voltage monitoring requires that v cc 4v, but out remains asserted in the correct undervoltage lockout state for v cc down to 1.5v. note 3: startup time is the time required for the internal regulator and reference to reach specified accuracy after the monitor is powered up from gnd. note 4: the open-drain output can be pulled up to a voltage greater than v cc but cannot exceed +28v. electrical characteristics (continued) (v cc = 4v to 28v, t a = -40? to +125?, unless otherwise specified. typical values are at t a = +25?.) (note 1) parameter symbol conditions min typ max units v cc 1.5v, i sink = 250?, out asserted, t a = -40? to +85? 0.4 output voltage low v ol v cc 4.0v, i sink = 1ma, out asserted, t a = -40? to +125? 0.4 v output leakage current i lkg v cc = 5v, v out = 28v (note 4) 500 na output short-circuit sink i sc out asserted, out = v cc 10 ma max6460 reference short-circuit current ref = gnd 7 ma t a = -40? to +85? 2.183 2.25 2.303 reference output voltage v ref t a = +85? to +125? 2.171 2.25 2.303 v load regulation sourcing: 0 i ref 100?, sinking: 0 |i ref | 300na 50 ?/? input offset voltage v offset -4.5 +4.5 mv input hysteresis 6mv input bias current i bias v in + = 1.4v, v in - = 1v -25 +25 na input offset current i offset 2pa common-mode voltage range cmvr 0 1.4 v common-mode rejection ratio cmrr 80 db comparator power-supply rejection ratio psrr v in + = v in - = 1.4v 80 db max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 4 maxim integrated typical operating characteristics (gnd = 0, r pullup = 10k ? , and t a = +25?, unless otherwise noted.) supply current vs. supply voltage max6457-60 toc01 v cc (v) i cc ( a) 22 16 10 2 4 6 8 10 12 0 428 t a = +25 c t a = +125 c t a = -40 c trip threshold voltage vs. temperature (0.5% hysteresis) max6457-60 toc02 temperature ( c) trip threshold voltage (v) 110 95 80 65 50 35 20 5 -10 -25 1.13 1.15 1.17 1.19 1.21 1.23 1.25 1.11 -40 125 v th + (rising) v th - (falling) trip threshold voltage vs. temperature (5% hysteresis) max6457-60 toc03 temperature ( c) trip threshold voltage (v) 110 95 80 65 50 35 20 5 -10 -25 1.13 1.15 1.17 1.19 1.21 1.23 1.25 1.11 -40 125 v th + (rising) v th - (falling) trip threshold voltage vs. temperature (8.3% hysteresis) max6457-60 toc04 temperature ( c) trip threshold voltage (v) 110 95 80 65 50 35 20 5 -10 -25 1.13 1.15 1.17 1.19 1.21 1.23 1.25 1.11 -40 125 v th + (rising) v th - (falling) output low voltage vs. output sink current max6457-60 toc05 i sink (ma) v ol (mv) 10 1 0.1 1 10 100 1000 10,000 100,000 0.1 0.01 100 t a = +125 c t a = +25 c t a = -40 c v cc = 12v max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 5 maxim integrated output short-circuit sink current vs. temperature max6457-60 toc06 temperature ( c) i sc (ma) 110 95 80 65 50 35 20 5 -10 -25 9 10 11 12 13 14 15 8 -40 125 v cc = 12v v cc = 5v v cc = 24v timeout period vs. temperature max6457-60 toc07 temperature ( c) t tp (ms) 110 95 80 65 50 35 20 5 -10 -25 0.1 1 10 100 1000 0.01 -40 125 max6457ukd3 max6457ukd0 output fall time vs. supply voltage max6457-60 toc08 v cc (v) output fall time (ns) 24 20 16 12 8 200 400 600 800 1000 1200 1400 1600 1800 2000 0 428 t a = +125 c t a = -40 c t a = +25 c maximum transient duration vs. input overdrive max6457-60 toc09 input overdrive (v th- - v in +) (mv) maximum transient duration ( s) 100 10 50 100 150 200 250 300 0 11000 out asserted low above this line max6457-60 toc10 temperature ( c) i in (na) 110 95 80 65 50 35 20 5 -10 -25 0 2 4 6 8 10 -2 -40 125 v in = 1.25v input leakage current vs. temperature typical operating characteristics (continued) (gnd = 0, r pullup = 10k ? , and t a = +25?, unless otherwise noted.) max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 6 maxim integrated pin description pin max6457 max6458 max6459 max6460 name function max6457: open-drain monitor output. out requires an external pullup resistor. out asserts low for v cc between 1.5v and 4v. out asserts low when v in+ drops below v th- and goes high after the timeout period (t tp ) when v in+ exceeds v th+ . max6458: open-drain monitor output. out requires an external pullup resistor. out asserts low for v cc between 1.5v and 4v. out asserts low when v in+ drops below v th- or when v in- exceeds v th+ . out goes high after the timeout period (t tp ) when v in+ exceeds v th+ and v in- drops below v th- . 1 1 1 out max6460: open-drain monitor output. out requires an external pullup resistor. out asserts low for v cc between 1.5v and 4v. out asserts low when v in+ drops below v in- . out goes high when v in+ is above v in- . 1 outa open-drain monitor a undervoltage output. outa requires an external pullup resistor. outa goes low when v in+ drops below v th- and goes high when v in+ exceeds v th+ . outa also goes low for v cc between 1.5v and 4v. 5 outb open-drain monitor b overvoltage output. outb requires an external pullup resistor. outb goes low when v in- exceeds v th+ and goes high when v in- drops below v th- . outb also goes low when v cc drops below 4v. 2 2 2 2 gnd ground 3333in+ adjustable undervoltage monitor threshold input. noninverting input for max6460. 4 4 4 in- adjustable overvoltage monitor threshold input. inverting input for max6460. 4 clear clear input. for v in+ > v th+ , drive clear high to latch out high. connect clear to gnd to make the latch transparent. clear must be low when powering up the device. connect clear to gnd when not used. 5 ref reference. internal 2.25v reference output. connect ref to in+ through a voltage divider for active-low output. connect ref to in- through a voltage divider for active-high output. ref can source up to 100? and sink up to 300na. leave ref floating when not used. ref output is stable with capacitive loads from 0 to 50pf or greater than 1?. 5566v cc supply voltage max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 7 maxim integrated max6458 v cc in+ in- gnd out 1.228v uv ov hysteresis option timeout option "uv": undervoltage "ov": overvoltage max6457 hysteresis option timeout option latch v cc in+ gnd out 1.228v clear max6459 v cc in+ in- gnd 1.228v uv ov hysteresis option "uv": undervoltage "ov": overvoltage outa outb max6460 v cc in+ in- ref gnd 2.25v out functional diagrams figure 1. max6457 functional diagram figure 2. max6458 functional diagram figure 3. max6459 functional diagram figure 4. max6460 functional diagram max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 8 maxim integrated detailed description each of the max6457?ax6460 high-voltage (4v to 28v), low-power voltage monitors include a precision bandgap reference, one or two low-offset-voltage com- parators, internal threshold hysteresis, internal timeout period, and one or two high-voltage open-drain outputs. programming the trip voltage (v trip ) two external resistors set the trip voltage, v trip (figure 5). v trip is the point at which the applied voltage (typically v cc ) toggles out. the max6457/max6458/max6459/ max6460? high input impedance allows large-value resistors without compromising trip-voltage accuracy. to minimize current consumption, select a value for r2 between 10k ? and 1m ? , then calculate r1 as follows: where v trip = desired trip voltage (in volts), v th = threshold trip voltage (v th + for overvoltage detection or v th - for undervoltage detection). use the max6460 voltage reference (ref) to set the trip threshold by connecting in+ or in- through a volt- age divider (within the inputs common-mode voltage range) to ref. do not connect ref directly to in+ or in- since this violates the input common-mode voltage range. small leakage currents into the comparators inputs allows use of large value resistors to prevent loading the reference and affecting its accuracy. figure 5b shows an active-high power-good output. use the following equation to determine the resistor values when connecting ref to in-: where v ref = reference output voltage (2.25v, typ), v refd = divided reference, v trip = desired trip thresh- old in (in volts). for an active-low power-good output, connect the resistor divider r1 and r2 to the inverting input and the reference-divider network to the noninverting input. alternatively, connect an external reference less than 1.4v to either input. rr v v trip refd 12 1 =? ? ? ? ? ? ? vv r rr refd ref = + ? ? ? ? ? ? 4 34 rr v v trip th 12 1 = ? ? ? ? ? ? - v cc in+ gnd out (outa for max6459) r1 v cc r2 r pullup out (outa) max6457 max6460 v trip = v th r1 + r2 r2 figure 5a. programming the trip voltage v cc in+ ref in- gnd r1 v trip v refd r2 r3 r4 r pullup out out max6460 figure 5b. programming the max6460 trip voltage v th+ v th- v in+ v out 0 v cc v hyst t tp t tp figure 6. input and output waveforms (noninverting input varied) max6457?ax6460 high-voltage, low-current voltage monitors in sot packages 9 maxim integrated hysteresis hysteresis adds noise immunity to the voltage monitors and prevents oscillation due to repeated triggering when v in is near the threshold trip voltage. the hystere- sis in a comparator creates two trip points: one for the rising input voltage (v th +) and one for the falling input voltage (v th -). these thresholds are shown in figure 6. the internal hysteresis options of the max6457/ max6458/max6459 are designed to eliminate the need for adding an external hysteresis circuit. timeout period the timeout period (t tp ) for the max6457 is the time from when the input (in+) crosses the rising input threshold (v th +) to when the output goes high (see figures 6 and 7). for the max6458, the monitored volt- age must be in the ?indow?before the timeout starts. the max6459 and max6460 do not offer the extended timeout option (150ms). the extended timeout period is suitable for overvoltage protection applications requir- ing transient immunity to avoid false output assertion due to noise spikes. latched-output operation the max6457 features a digital latch input ( clear ) to latch any overvoltage event. if the voltage on in+ (v in +) is below the internal threshold (v th -), or if v cc is below 4v, out remains low regardless of the state of clear . drive clear high to latch out high when v in + exceeds v th +. when clear is high, out does not deassert if v in + drops back below v in -. toggle clear to deassert out. drive clear low to make the latch transparent (figure 7). clear must be low when powering up the max6457. to initiate self-clear at power-up, add a 100k ? pullup resistor from clear to v cc and a 1? capacitor from clear to gnd to hold clear low. connect clear to gnd when not used. see figure 9. in+ out >v th+ |