_______________general description the max1614 drives high-side, n-channel power mosfets to provide battery power-switching functions in portable equipment. the n-channel power mosfets typically have one-third the on-resistance of p-channel mosfets of simi- lar size and cost. an internal micropower regulator and charge pump generate the high-side drive output voltage, while requiring no external components. the max1614 also features a 1.5%-accurate low-battery comparator that can be used to indicate a low-battery condition, provide an early power-fail warning to the sys- tem microprocessor, or disconnect the battery from the load, preventing deep discharge and battery damage. an internal latch allows for pushbutton on/off control with very low current consumption. off-mode current consumption is only 6? while normal operation requires less than 25?. the max1614 is available in the space-saving ?ax package that occupies about 60% less space than a standard 8-pin so. ________________________applications notebook computers portable equipment hand-held instruments battery packs ____________________________features internal on/off latch high-side, n-channel power mosfet drive 25 a (max) quiescent current 6 a (max) off current requires no external components 1.5%-accurate low-battery detector space-saving max package 5v to 26v input voltage range drives single or back-to-back mosfets controlled turn-on for low inrush current max1614 high-side, n-channel mosfet switch driver ________________________________________________________________ maxim integrated products 1 1 + 2 3 4 8 7 6 5 batt src gate gnd lbi lbo off on max1614 max top view part temp range pin-package max1614c/d 0? to +70? dice* MAX1614EUA+ -40? to +85? 8 ?ax MAX1614EUA/v+ -40? to +85? 8 ?ax __________________pin configuration max1614 off lbo gnd lbi batt src gate on nn load optional for reverse current protection r1 r2 __________typical operating circuit 19-1176; rev 1; 6/11 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. ______________ordering information * contact factory for dice specifications. + denotes a lead(pb)-free/rohs-compliant package. /v denotes an automotive qualified part. devices are also available in a tape-and-reel package. specify tape-and-reel by adding ??to the part number when ordering. ?ax is a registered trademark of maxim integrated products, inc.
? max1614 high-side, n-channel mosfet switch driver 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v batt = 15v, t a = 0c to +85c, unless otherwise noted. typical values are at t a = +25?.) 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. batt, src to gnd.................................................-0.3v to +30v gate to src ..........................................................-0.3v to +12v gate to gnd .........................................................-0.3v to +36v gate + src sink current, continuous .............................2.7ma lbi, lbo , on , off to gnd....................................-0.3v to +12v lbo current ..........................................................................5ma continuous power dissipation (t a = +70?) ?ax (derate 4.10mv/? above +70?) .....................330mw operating temperature range ...........................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +160? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) .......................................+260? v batt = 15v, on = off = unconnected, i gate = 0a, device latched on, v lbi = 1.5v, src = batt v batt = 5v v batt = 26v, on = off = unconnected, i gate = 0a, device latched off, v lbi = 1.5v v batt = 26v v gate - v src > 3v, src = batt v batt = 5v tested at 0.6v tested at 2v tested at v lbi = v batt / 4 v lbo = 11.5v lbi input falling measured from gate to src, v batt = 15v, i gate = 0a v gate = v src = 15v i sink = 1ma v gate = 4v, device latched off v lbi = 1.3v conditions ? 0.5 1.0 t pw minimum input pulse width v 2.0 v ih input high voltage v 0.6 v il input low voltage ? 1.5 2 maximum input pullup current ? 0.5 minimum input pullup current ? 0.5 v oh lbo high leakage v 0.4 v ol lbo low voltage na 10 i lbi lbi input current 17 30 ? 47 i shdn v 526 batt operating range batt shutdown current v 0.9 4 minimum v batt for valid lbo v 0.02v th lbi trip hysteresis v 1.182 1.20 1.218 v th lbi trip level v 6.5 8 9.0 v gs gate drive voltage ? 15 60 gate drive output current ma 0.5 2 gate discharge current units min typ max symbol parameter v batt = 26v, on = off = unconnected, i gate = 0a, device latched on, v lbi = 1.5v, src = batt 21 40 measured from gate to src, v batt = v src = 5v, i gate = 1.5? 3 ? i batt + i src quiescent current internal charge pump low-battery comparator control inputs ( o o n n , o o f f f f )
max1614 high-side, n-channel mosfet switch driver _______________________________________________________________________________________ 3 electrical characteristics (v batt = 15v, t a = -40c to +85c, unless otherwise noted.) (note 1) __________________________________________typical operating characteristics (t a = +25?, unless otherwise noted.) 22 6 530 on supply current vs. v batt max1614-01 v batt (v) supply current ( a) 20 14 10 10 15 18 20 12 8 16 25 t a = +85? t a = +25? t a = -40? 4.0 1.0 530 off supply current vs. v batt max1614-02 v batt (v) shutdown current ( a) 20 3.0 2.0 10 15 2.5 1.5 3.5 25 t a = +25 c t a = -40 c t a = +85 c note 1: specifications to t a = -40? are guaranteed by design and not production tested. low battery comparator internal charge pump 3 measured from gate to src, v batt = 5.25v, i gate = 1.5?, v src = 5.25v 40 parameter symbol min typ max units gate drive output current 15 60 ? gate drive voltage v gs 6.5 9.0 v lbi trip level v th 1.176 1.20 1.224 v batt shutdown current batt operating range 5.0 26 v i shdn 8 ? quiescent current i batt + i sac ? conditions v gate = v src = 15v measured from gate to src, v batt = 15v, i gate = 0a lbi input falling v gate - v src > 3v, src = batt v batt = 26v, on = off = unconnected, i gate = 0a, device latched off, v lbi = 1.5v v batt = 26v, on = off = unconnected, i gate = 0a, device latched on, v lbi = 1.5v internal charge pump low-battery comparator 1.30 1.16 -40 100 low-battery threshold vs. temperature max1614-05 temperature ( c) lbi threshold (v) 40 1.24 1.20 -20 0 1.22 1.18 1.26 1.28 80 20 60 v batt = 15v v lbi rising v lbi falling
max1614 high-side, n-channel mosfet switch driver 4 _______________________________________________________________________________________ ____________________________typical operating characteristics (continued) (t a = +25?, unless otherwise noted.) 2.5 -0.5 020 gate-discharge current vs. gate voltage max1614-04 v gate (v) gate-discharge current (ma) 12 1.5 0.5 48 1.0 0 2.0 16 214 610 18 t a = +85 c t a = +25 c t a = -40 c 30 22 530 gate-charging current vs. batt voltage max1614-06 v batt (v) gate-charging current ( a) 25 27 25 10 15 26 24 28 29 23 20 t a = +85 c t a = -40 c 5v/div gate and source transitions for typical mosfet load 1ms/div si9936 mosfets i load = 1a on = gnd v gate v src v off max1614-07 5v/div gate turn-on transition for typical mosfet load 100 s/div si9936 mosfets i load = 1a c iss = 400pf on = gnd v gate v src v off max1614-08 0v 0v 5v/div gate turn-off transition for typical mosfet load 20 s/div si9936 mosfets i load = 1a c iss = 400pf on = gnd v off max1614-09 v gate v src 34 26 -40 0 80 100 gate-charging current vs. temperature 28 27 max1614--03 temperature (?) gate-charging current ( a) 40 -20 60 20 32 30 33 31 29 v batt = 15v
max1614 high-side, n-channel mosfet switch driver _______________________________________________________________________________________ 5 _______________detailed description the max1614 uses an internal, monolithic charge pump and low-dropout linear regulator to supply the required 8v v gs voltage to fully enhance an n-channel mosfet high-side switch (figure 1). the charge pump typically supplies 30?, charging 800pf of gate capacitance in 400? (v batt = 15v). for slower turn-on times, simply add a small capacitor between the gate and src pins. when turned off, gate and src pull low and typi- cally discharge an 800pf gate capacitance in 80?. the max1614 provides separate on/off control inputs ( on and off ). on and off connect, respectively, to the set and reset inputs of an internal flip-flop. when on is pulsed low (with off = high), the internal charge pump turns on, and gate is pumped to 8v above src, turning on the external mosfets. the charge pump maintains gate drive to the external mosfets until off is pulsed low. when this happens, the internal charge pump turns off, and gate discharges to ground through an internal switch. for slower turn-on times, simply add a small capacitor. __________ applications information connecting on / off to 3v or 5v logic on and off internally connect to 2? max pullup current sources (figure 1). the open-circuit voltage for on and off ranges from 7v to 10.5v (nominally 8.5v). since the current sources are relatively weak, connecting on and off directly to logic powered from lower voltages (e.g., 3v or 5v) poses no problem if the gate outputs driving these pins can sink at least 2? while high. although the max1614 shutdown function was designed to operate with a single pushbutton on/off switch, it can also be driven by a single gate. connect on to gnd and drive off directly (figure 2). maximum switching rate the max1614 is not intended for fast switching appli- cations. in fact, it is specifically designed to limit the rate of change of the load current, ? i/ ? t. the maximum switching rate is limited by the turn-on time, which is a function of the charge-pump output current and the total capacitance on gate (c gate ). calculate the turn- on time as a function of external mosfet gate capaci- tance using the gate charging current vs. v batt graph in the typical operating characteristics . since turn-off time is small compared to turn-on time, the maximum switching rate is approximately 1/t on . adding gate capacitance the charge pump uses an internal monolithic transfer capacitor to charge the external mosfet gates. normally, the external mosfet? gate capacitance is sufficient to serve as a reservoir capacitor. if the mosfets are located at a significant distance from the max1614, place a local bypass capacitor (100pf typ) across the gate and src pins. for slower turn-on times, simply add a small capacitor between gate and src. ______________________________________________________________pin description system ground gnd 5 gate-drive output. connect to the gates of external, n-channel mosfets. when the max1614 is off, gate actively pulls to gnd. gate 6 source input. connect to the sources of external, n-channel mosfets. when the max1614 is off, src actively pulls to gnd. src 7 battery input. connect to a battery voltage between 5v and 26v. batt 8 low-battery comparator input. lbo goes low when v lbi falls below 1.20v (typ). connect a voltage divider between batt, lbi, and gnd to set the battery undervoltage trip threshold (see typical operating circuit ). lbi 4 open-drain, low-battery comparator output. lbo is low when v lbi is below the trip point. lbo 3 pin reset input to the on/off latch. pulse off low with on high to turn off the external mosfet switch. when both on and off are low, the part is off. off 2 set input to the on/off latch. pulse on low with off high to turn on the external mosfet switch. when both on and off are low, the part is off. on 1 function name
max1614 high-side, n-channel mosfet switch driver 6 _______________________________________________________________________________________ 8.5v ldo 50khz osc soft start on 0 0 1 1 off 0 1 0 1 state off on off last valid state p batt power-on reset (batt < 2v) 1.21v lbi on n n gnd n p 1 a 1 a gate src c pump lbo off on max1614 figure 1. functional diagram
max1614 high-side, n-channel mosfet switch driver _______________________________________________________________________________________ 7 on/off control with a single pushbutton switch the max1614? separate on and off inputs allow maxi- mum flexibility in controlling the external mosfets. connect a pushbutton switch to the on pin and micro- controller (?) i/o for single-button control. connect the off pin to another ? i/o pin. on the first button depression, the max1614 turns on automatically; the signal is also detected by the ?. when the button is depressed a second time, the ? wraps around and turns off the max1614 by pulling low on the off pin (figure 3). simple low-battery disconnect/fresh battery reconnect circuit a simple undervoltage disconnect circuit is often desir- able to prevent damage to secondary batteries due to repeated deep discharge or cell reversal. the typical operating circuit turns off the max1614, disconnecting the battery from the load when the battery voltage falls below the minimum battery voltage required, (v low batt ). v low batt = (r1 + r2)/r2 x v th where v th is the lbi input threshold (1.20v typ). when fresh cells are installed or the batteries are recharged, a ? or pushbutton reconnects the load. using lbo to generate early power-fail interrupt many applications require an early warning indicating that power is failing so that the microprocessor (?) can take care of any ?ousekeeping?functions (storing current settings in memory, etc.) before the power fails. connect lbi through a resistor divider across the bat- tery, and connect lbo to the ? nonmaskable interrupt (nmi). set the threshold so that lbo goes low when the battery decays to a point where regulation begins to degrade (figure 4). v low batt = (r1 + r2)/r2 x v th, where v th is the lbi input threshold (1.20v typ). once housekeeping is complete, the ? can turn off the load by pulling off low. max1614 shutdown (cmos or ttl logic) gnd on off figure 2. single-line shutdown control max1614 off lbo gnd lbi batt src gate on nn load to ? r1 r2 figure 3. single-pushbutton on/off control max1614 off lbo gnd lbi batt src gate on nn load to ? port pins to ? nonmaskable interrupt r1 r2 figure 4. using lbo to generate early power-fail interrupt
max1614 high-side, n-channel mosfet switch driver 8 _______________________________________________________________________________________ increasing low-battery comparator hysteresis the max1614 contains an on-chip comparator with 2% hysteresis for low-battery detection. if more than 2% hysteresis is needed on the low-battery comparator and lbo is connected to off, use the circuit in figure 5 to add hysteresis. the circuit of figure 5 shows lbo con- trolling an n-channel mosfet that shorts r2 to add pos- itive feedback to the trip point. this is necessary to prevent loading down the 1? pullup at off (figure 1). ___________________chip information substrate connected to gnd max1614 off lbo gnd lbi src gate n on batt load r2 n 2n7002 (sot23) r1 r3 r1 = 909k ? r2, r3 = 150k ? v l = 8.5v v h = 9.8v hysteresis = 6% falling trip point v l v l = v th ( ) rising trip point v h v h = v th ( ) r1 + r2 + r3 r3 r1 + r3 r3 figure 5. increasing hysteresis of the battery disconnect circuit package information for the latest package outline information and land patterns (footprints), go to www.maxim-ic.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. package type package code outline no. land pattern no. 8 ?ax u8+1 21-0036 90-0092
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. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 _____________________ 9 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. max1614 high-side, n-channel mosfet switch driver revision history revision number revision date description pages changed 0 12/96 initial release 1 6/11 added automotive-qualified part to the ordering information, added soldering temperature to the absolute maximum ratings. 1, 2
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