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| mpq4462 3.5a, 4mhz, 36v, step-down converter aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 1 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. the future of analog ic technology description the mpq4462 is a high-frequency, step-down, switching regulator with an integrated, high-side, high-voltage, power mosfet. it provides a 3.5a output with current-mode control for fast loop response and easy compensation. the wide 3.8v-to-36v input range accommodates a variety of step-down applications, including those in an automotive input environment. a 120a operational quiescent current allows for battery-powered applications. switching-frequency scaling allows for high power-conversion efficiency over a wide load range by scaling down the switching frequency at light loads to reduce the switching and gate driving losses. the frequency foldback prevent inductor-current runaway during startup, and thermal shutdown provides reliable and fault tolerant operation. the mpq4462 can operate at up to 4mhz for emi-sensitive applications, such as am radio and adsl applications. the mpq4462 is available in both 3mm3mm qfn10 and soic8e packages. features ? 120 a quiescent current ? wide 3.8v-to-36v input range ? 150m ? internal power mosfet ? up to 4mhz programmable switching frequency ? stable with a ceramic capacitor ? internal soft-start ? internally-set current limit without a current sensing resistor ? output adjustable from 0.8v to 30v ? available in 3mm3mm qfn10 and soic8e packages. ? available in aec-q1000 qualified grade 1 applications ? high-voltage power conversion ? automotive systems ? industrial power systems ? distributed power systems ? battery powered systems all mps parts are lead-free and adhere to the rohs directive. for mps green status, please visit mps website under products, quality assurance page. ?mps? and ?the future of analog ic technology? are registered trademarks of monolithic power systems, inc. typical application
mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 2 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. ordering information part number package top marking mpq4462dq * qfn10 (3mm3mm) z2 mpq4462dn ** soic8e mp4462dn mpq4462dq-aec1 * qfn10 (3mm3mm) z2 MPQ4462DN-AEC1 ** soic8e mp4462dn *for tape & reel, add suffix ?z (e.g. mpq4462dq?aec1-z); for rohs, compliant packaging, add suffix ?lf (e.g. mpq4462dq?aec1-lf?z). **for tape & reel, add suffix ?z (e.g. mpq4462dn?aec1-z); for rohs, compliant packaging, add suffix ?lf (e.g. mpq4462dn?aec1-lf?z). package reference sw en comp fb bst vin freq gnd 1 2 3 4 8 7 6 5 top view qfn10 soic8e absolute maxi mum ratings (1) supply voltage (v in ).....................?0.3v to +40v switch voltage (v sw )............ ?0.3v to v in + 0.3v bst to sw .....................................?0.3v to +6v all other pins .................................?0.3v to +6v continuous power dissipation (t a = +25c) (2) qfn10 (3mmx3mm) .................................. 2.5w soic8e...................................................... 2.5w junction temperature ...............................150c lead temperature ....................................260c storage temperature.............. ?65c to +150c recommended operating conditions (3) supply voltage v in ...........................3.8v to 36v output voltage v out .........................0.8v to 30v operating junct. temp. .......... ?40c to +125c thermal resistance (4) ja jc qfn10 (3mm3mm)............... 50 ...... 12... c/w soic8e .................................. 50 ...... 10... c/w notes: 1) exceeding these ratings may damage the device. 2) the maximum allowable power dissipation is a function of the maximum junction temperature t j (max), the junction-to- ambient thermal resistance ja , and the ambient temperature t a . the maximum allowable continuous power dissipation at any ambient temperature is calculated by p d (max) = (t j (max)-t a )/ ja . exceeding the maximum allowable powe r dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. internal thermal shutdown circuitry protects the device from permanent damage. 3) the device is not guaranteed to function outside of its operating conditions. 4) measured on jesd51-7, 4-layer pcb. top view sw sw en comp fb 1 2 3 4 5 bst vin vin freq gnd 10 9 8 7 6 exposed pad on backside mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 3 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. electrical characteristics v in = 12v, v en = 2.5v, v comp = 1.4v, t j = ? 40c to +125c, unless otherwise noted. typical values are at t j = 25c. parameter symbol condition min typ max units v in = 4.5v to 36v, t j = 25c 0.786 0.792 0.803 feedback voltage v fb v in = 4.5v to 36v 0.773 0.812 v upper switch on resistance (5) r ds(on) v bst ? v sw = 5v 150 m ? upper switch leakage v en = 0v, v sw = 0v, v in = 36v 0.01 1 a current limit duty cycle = 50% 4.0 5.5 a comp to current sense transconductance (5) g cs 9 a/v error amp voltage gain (6) 200 v/v error amp transconductance i comp = 3a 35 60 95 a/v error amp min source current v fb = 0.7v 5 a error amp min sink current v fb = 0.9v ?5 a vin uvlo threshold 2.6 3.0 3.4 v vin uvlo hysteresis 400 mv soft-start time (5) v fb = 0v to 0.8v 1.5 ms oscillator frequency r freq = 45.3k ? 1.6 2 2.4 mhz shutdown supply current v en = 0v 11 18 a quiescent supply current no load, v fb = 0.9v 120 160 a thermal shutdown (5) 150 c thermal shutdown hysteresis (5) 15 c minimum off time (5) 100 ns minimum on time (5) 80 ns en rising threshold 1.4 1.5 1.7 v en falling threshold 1.1 1.2 1.4 v en threshold hysteresis 300 mv note: 5) derived from bench characteri zation. not tested in production. 6) guaranteed by design. not tested in production. mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 4 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. pin functions qfn pin # soic8e pin # name description 1, 2 1 sw switch node. output of the high-side swit ch. requires a low-forward-drop schottky diode to ground. place the diode close to the sw pins to reduce switching spikes. 3 2 en enable. pull below the specified threshold to shut the chip down. pull it up above the specified threshold or leave it floating to enable the chip. 4 3 comp compensation. output of the error ampl ifier. includes control-loop frequency compensation. 5 4 fb feedback. input to the error amplifier. the tap of a resistor divider between the output and gnd sets the output voltage to the internal +0.8v reference. 6 5 gnd ground. 7 6 freq switching frequency set. connect a resistor from this pin to ground to set the switching frequency. 8, 9 7 vin input supply. supplies power to all internal control circuitry. requires a decoupling capacitor to ground to minimize switching spikes. 10 8 bst bootstrap. positive power supply to the in ternal, floating, high-side mosfet driver. connect a bypass capacitor between this pin and sw. exposed pad ground pad. connect to gnd plane for optimal thermal performance. mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 5 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. typical characteristics mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 6 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. typical characteristics (continued) mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 7 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. typical performanc e characteristics v in = 12v, v out = 3.3v, c1 = 10f, c2 = 22f, l = 10h and t a = +25c, unless otherwise noted. mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 8 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. typical performanc e characteristics (continued) v in = 12v, v out = 3.3v, c1 = 10f, c2 = 22f, l = 10h and t a = +25c, unless otherwise noted. mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 9 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. block diagram figure 1: functional block diagram mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 10 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. operation the mpq4462 is a variable-frequency, asynchronous, step-down switching regulator with an integrated, high-side, high-voltage, power mosfet. it provides a highly efficient output with current mode control for fast loop response and easy compensation. it features a wide input-voltage range, internal soft-start control, and precise current limiting. its very-low operational quiescent current makes it suitable for battery-powered applications. pwm control at moderate-to-high output current, the mpq4462 operates in a fixed-frequency, peak- current-control mode to regulate the output voltage. the internal clock initiates a pwm cycle that turns the power mosfet on. this mosfet remains on until its current reaches the value set by v comp . when the power mosfet is off, it remains off for at least 100ns before the next cycle starts. if the current in the power mosfet does not reach the comp set current value within one pwm period, the power mosfet remains on to save a turn-off operation. error amplifier the error amplifier compares v fb to the internal reference (v ref ) and outputs a current proportional to the difference between the two. this output current charges the external compensation network to form v comp , which controls the power mosfet current. while operating, the v comp minimum is clamped to 0.9v and its maximum is clamped to 2.0v. comp is internally pulled down to gnd in shutdown mode. comp should not be pulled up beyond 2.6v. internal regulator the 2.6v internal regulator powers most of the internal circuits. this regulator takes v in and operates in the full v in range. when v in exceeds 3.0v, the output of the regulator is in full regulation. when vin falls below 3.0v, the output decreases. enable control the mpq4462 has a dedicated enable-control pin (en). enable uses logic-high to enable and disable the chip. its falling threshold is precisely 1.2v, and its rising threshold is 1.5v (300mv higher). when floating, en is pulled up to about 3.0v by an internal 1a current source to remain enabled. to pull-down requires a 1a current. when v en is pulled down below 1.2v, the chip enters its lowest shutdown current mode. when v en exceeds 0v but remains below its rising threshold, the chip remains in shutdown mode but the shutdown current increases slightly. under-voltage lockout (uvlo) under-voltage lockout (uvlo) protects the chip from operating at insufficient supply voltages. the uvlo rising threshold is about 3.0v while its falling threshold is a consistent 2.6v. internal soft-start the soft-start prevents the converter output voltage from overshooting during startup. when the chip starts, the internal circuitry generates a soft-start voltage (v ss ) that ramps up from 0v to 2.6v. when v ss mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 11 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. if v in is sufficiently higher than v sw , the bootstrap capacitor charges. when the power mosfet is on, v in v sw so the bootstrap capacitor cannot charge. when the external diode is on, the v in ? v sw is at its maximum for optimal charging. when there is no current in the inductor, v sw =v out so v in ? v out charges the bootstrap capacitor. at higher duty cycles, the bootstrap-charging period is shorter so the bootstrap capacitor may not charge sufficiently. if the internal circuit does not have sufficient voltage and the bootstrap capacitor is not charged, an external circuit can ensure the bootstrap voltage is in the normal operational region. the floating driver?s dc quiescent current ~20a. select a bleeding current at the sw node meets the following criterion: a 20 ) 2 r 1 r ( v i o o > + + current comparator and current limit a current-sense mosfet accurately senses the power-mosfet current. the sense value is compared to v comp by a high-speed current comparator. when the power mosfet turns on, the comparator is first blanked till the end of the turn-on transition. when the sensed current exceeds v comp , the comparator output is low, turning off the power mosfet. the cycle-by- cycle maximum current of the internal power mosfet is internally limited. startup and shutdown if both v in and v en exceed their respective thresholds, the chip starts. the reference block starts first, generating stable reference voltage and currents, and then the internal regulator is enabled. the regulator provides a stable supply for the remaining circuits. while the internal supply rail is up, an internal timer holds the power mosfet off for about 50s to blank the startup noise. when the internal soft-start block is enabled, it first holds v ss low before slowly ramping up. three events can shut down the chip: v en low, v in low, and thermal shutdown. for shutdown, the power mosfet turn off to avoid triggering any faults. v comp and the internal supply rail are then pulled down. programmable oscillator an external resistor (r freq ) from the freq pin to ground sets the mpq4462 oscillating frequency. mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 12 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. application information `component selection frequency the mpq4462 has an externally-adjustable frequency using r freq . see table1 for a list of recommended r freq value for various f s . table 1: f s vs. r freq r freq (k ? ) f s (mhz) 18 4 20 3.8 22.1 3.5 24 3.3 26.7 3 30 2.8 33.2 2.5 39 2.2 45.3 2 51 1.8 57.6 1.6 68 1.4 80.6 1.2 100 1 133 0.8 200 0.5 340 0.3 536 0.2 output voltage connecting fb to the tap of a resistor divider from v out to ground sets v out such that: 2 r ) 2 r 1 r ( v v fb out + = without a load, the mpq4462 outputs ~20a from its high-side bst circuitry. keep r2 40k ? to absorb this small amount of current. selecting r2=40.2k ? , r1 is then: out r1 50.25 (v 0.8)(k ) =? for example, for v out =3.3v and r2=40.2k ? , then r1 is 127k ? . inductor the inductor supplies constant current to the output load while being driven by the switching input voltage. a larger inductor will reduce ripple current and lower output ripple voltage, but is physically larger, and have a higher series resistance and/or lower saturation current. to choose a balanced inductor value, allow the peak-to-peak inductor ripple current approximately equal 30% of the maximum switching current limit. to ensure that the peak inductor current is below the maximum switch current limit estimate and inductor value as: out out sl in vv l1 1 f iv ?? =? ?? ?? where v out is the output voltage, v in is the input voltage, f s is the switching frequency, and i l is the peak-to-peak inductor-ripple current. choose an inductor that will not saturate under the maximum inductor peak current, which is: out out lp load sin vv ii 1 2f l1 v ?? =+ ? ?? ?? where i load is the load current. output rectifier diode the output rectifier diode supplies the current to the inductor when the high-side switch is off. to reduce losses due to the diode forward voltage and recovery times, use a schottky diode. choose a diode whose maximum reverse voltage rating exceeds the maximum input voltage, and whose current rating exceeds the maximum load current. input capacitor the input current to the step-down converter is discontinuous and requires a capacitor to supply the ac current to the step-down converter while maintaining the dc input voltage. use low-esr capacitors for the best performance. ceramic capacitors are best, but tantalum or low-esr electrolytic capacitors may also suffice. mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 13 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. for simplicity, choose an input capacitor with an rms current rating greater than half of the maximum load current. the input capacitor (c1) can be electrolytic, tantalum, or ceramic. electrolytic or tantalum capacitors will need a small, high-quality ceramic capacitor (0.1 f) placed as close to the ic as possible. ceramic capacitors must have enough capacitance to prevent excessive input voltage ripple. the capacitor-incurred input voltage ripple is approximately: load out out in in sin iv v v1 fc1v v ?? = ? ?? ?? output capacitor the output capacitor (c2) maintains the output dc voltage. use ceramic, tantalum, or low-esr electrolytic capacitors. low-esr capacitors are best at limiting the output voltage ripple. the output voltage ripple is approximately: out out out esr sin s vv 1 v1r fl v 8fc2 ?? ?? = ? + ?? ?? ?? ?? where l is the inductor and r esr is the output capacitor?s equivalent series resistance. if using ceramic capacitors, the capacitance dominates the impedance at the switching frequency and contributes to the majority of the output voltage ripple. the output voltage ripple is approximately: out out out 2 sin vv v1 8f lc2 v ?? =? ?? ?? if using either tantalum or electrolytic capacitors, the esr dominates the impedance at the switching frequency. the output ripple is approximately: out out out esr in s vv v1r fl v ?? =? ?? ?? the output capacitor also affects the regulatory- system?s stability. the mpq4462 can be optimized for a wide range of capacitances and esr values. compensation components the mpq4462 employs current-mode control for easy compensation and fast transient response. the comp pin?the output of the internal error amplifier?controls system stability and transient response. a series rc combination adds a pole-zero pair to the control system . the dc gain of the voltage feedback loop is: fb vdc load cs vea out v arga v = where a vea is the error amplifier voltage gain (200v/v) g cs is the current sense transconductance (9a/v), and r load is the load resistor value. the system has two important poles: the compensation capacitor (c3) and the error amplifier?s output resistor; and the output capacitor and the load resistor. these poles are located at: ea p1 vea g f 2c3a = p2 load 1 f 2c2r = where, g ea is the error amplifier?s transconductance, 60 a/v. the system has one important zero due to the compensation capacitor (c3) and the compensation resistor (r3). this zero is located at: z1 1 f 2c3r3 = the system may have another important zero if the output capacitor is large and/or has a high- esr. the zero is located at: esr esr 1 f 2c2r = in case requires a third pole set by the compensation capacitor (c6) and the mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 14 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. compensation resistor (r3). this pole is located at: p3 1 f 2c6r3 = the compensator shapes the converter transfer function for a desired loop gain. the feedback loop?s unity-gain crossover frequency is important. lower crossover frequencies result slow line and load transient responses, while higher crossover frequencies increase system instability. for most applications, set the crossover frequency to ~0.1f s . table 2 lists some typical compensation-component values for standard output voltages. the component values are optimized for fast transient responses and good stability at given conditions. table 2: compensation values for typical output voltage/capacitor combinations v out (v) l (h) c2 (f) r3 (k ? ) c3 (pf) c6 1.8 4.7 47 105 100 none 2.5 4.7 - 6.8 22 54.9 220 none 3.3 6.8 -10 22 68.1 220 none 5 15 - 22 22 100 150 none 12 22 - 33 22 147 150 none to optimize the compensation components for conditions not listed in table 2: 1. choose r3 for the desired crossover frequency: cout ea cs fb 2c2f v r3 gg v = where f c is the desired crossover frequency. 2. choose c3 for the desired phase margin. for applications with typical inductor values, setting the compensation zero (f z1 ) below 0.25f c provides sufficient phase margin. c3 must meet the following criterion: c f 3 r 2 4 3 c > 3. determine if c6 is required. add c6 if the esr zero of the output capacitor is located at <0.5f c , or if the following relationship is true: s esr f 1 2c2r 2 < select c6 to set the pole (f p3 ) at the the esr zero. determine the c6 as: esr c2 r c6 r3 = high-frequency operation set the mp4462?s switching frequency up to 4mhz through an external resistor. for switching frequencies above 2mhz, take the following into consideration: ? the minimum on-time is ~80ns. pulse skipping occurs more often at higher switching frequencies due to the minimum on-time. ? the recommended operating voltage is <12v, and <24v at 2mhz. refer to figure 2 for more information. recommended v in (max) vs switching frequency 30 25 20 15 10 5 1500 2000 2500 3000 3500 4000 v out =3.3v f s (khz) v in (max) (v) v out =2.5v figure 2: recommended max. v in vs f s mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 15 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. ? the internal bootstrap circuit?s impedance may limit the charge to the bootstrap capacitor during each (1-d)t s charging period. add an external bootstrap charging diode if the switching frequency is above 2mhz. ? at higher switching frequencies, the capacitor?s inductive reactance (xl dominates, so that the esl of the input/output capacitor determines the input/output ripple voltage at higher switching frequencies. select a high- frequency ceramic capacitor as the input decoupling capacitor and the output filtering capacitor for high-frequency operation. ? layout becomes more important when the device switches at higher frequencies. please refer to the pcb layout guide for more details. external bootstrap diode add an external bootstrap diode if the input voltage is no greater than 5v or if the 5v rail is available. this diode improves regulator efficiency. the bootstrap diode can be a low- cost one, such as the in4148 or the bat54. sw bs 5v figure 3: external bootstrap diode this diode is also recommended for high-duty- cycle operation (when v out /v in >65%) or low v in (<5v) applications. at no load or light load, the converter may operate in pulse-skipping mode to maintain output-voltage regulation. however, pulse- skipping limits the bst voltage?s charging time. for sufficient gate voltage, make sure that v in ? v out >3v. for example, if v out is 3.3v, v in needs to be higher than 3.3v+3v=6.3v to maintain the bst voltage at no load or light load. to meet this requirement, use the en pin to program the input uvlo voltage to v out +3v. mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 16 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. typical application circuits c6 ns d1 v out 1.8v v in 6v - 36v vin en freq gnd bst sw fb comp en 6 10 1,2 5 4 8,9 3 7 figure 4: typical application, 1.8v output c6 ns d1 v out 5v v in 10v - 36v vin en freq gnd bst sw fb comp en 6 10 1,2 5 4 8,9 3 7 figure 5: typical application, 5v output mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 17 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. pcb layout guide pcb layout is very important for system stability. it is highly recommended to duplicate evb layout for optimum performance. if change is necessary, please follow these guidelines and take figure 6 for reference. 1) keep the path of switching current short and minimize the loop area formed by input capacitor, high-side mosfet and external switching diode. place ceramic bypass capacitors close to the vin pin. 2) make all feedback connections short and direct. try to run the feedback trace as far from the inductor and noisy power traces as possible. if possible run the feedback trace on the opposite pcb side to the inductor with a ground plane separating the two. 3) place the feedback resistors and compensation components as close to the chip as possible. do not place the compensation components close to or under high dv/dt sw node, or inside the high di/dt power loop. if you have to do so, the proper ground plane must be in place to isolate those. 4) connect vin, sw, and especially gnd respectively to large copper areas to cool the chip to improve thermal performance and long-term reliability. to help to improve the thermal conduction at high frequencies, add a grid of thermal vias under the exposed pad. use small vias (15mil barrel diameter) so that the hole fills up during the plating process and improve thermal conduction. larger vias can cause solder wicking during the reflow process. a pitch (distance between the centers) of 40mil between thermal vias is typical. 5) place the input decoupling capacitor, catch diode and the mpq4462 (vin, sw and pgnd) as close as possible, with traces that are very short and fairly wide. this can help to greatly reduce the voltage spike on sw node, and lower the emi noise level as well. 6) please refer to the layout example on evq4460 datasheet. c1 c3 r2 r1 l1 c4 c2 d1 v out v in vin en freq gnd bst sw fb comp en r5 r6 r3 r4 figure 6: typical application circuit mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 18 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. mpq4462dq top layer mpq4462dq bottom layer c4 c1 r2 r3 c3 r1 r5 r4 gnd gnd vin vo sw l1 c2 sw en fb d1 sw comp r6 gnd vin freq bst 6 7 8 1 2 3 4 5 10 9 vin gnd mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified mpq4462 rev. 1.11 www.monolithicpower.com 19 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. package information 3mm x 3mm qfn10 mpq4462 ? 3.5a, 4mhz, 36v, step-dow n converter, aec-q100 qualified notice: the information in this document is subject to change wi thout notice. users should warra nt and guarantee that third party intellectual property rights are not infringed upon w hen integrating mps products into any application. mps will not assume any legal responsibility for any said applications. mpq4462 rev. 1.11 www.monolithicpower.com 20 7/17/2013 mps proprietary information. patent protec ted. unauthorized photocopy and duplication prohibited. ? 2013 mps. all rights reserved. soic8e see detail "a" 0.0075(0.19) 0.0098(0.25) 0.050(1.27) bsc 0.013(0.33) 0.020(0.51) seating plane 0.000(0.00) 0.006(0.15) 0.051(1.30) 0.067(1.70) top view front view side view bottom view note: 1) control dimension is in inches. dimension in bracket is in millimeters. 2) package length does not include mold flash, protrusions or gate burrs. 3) package width does not include interlead flash or protrusions. 4) lead coplanarity (bottom of leads after forming) shall be 0.004" inches max. 5) drawing conforms to jedec ms-012, variation ba. 6) drawing is not to scale. 0.089(2.26) 0.101(2.56) 0.124(3.15) 0.136(3.45) recommended land pattern 0.213(5.40) 0.063(1.60) 0.050(1.27) 0.024(0.61) 0.103(2.62) 0.138(3.51) 0.150(3.80) 0.157(4.00) pin 1 id 0.189(4.80) 0.197(5.00) 0.228(5.80) 0.244(6.20) 14 85 0.016(0.41) 0.050(1.27) 0 o -8 o detail "a" 0.010(0.25) 0.020(0.50) x 45 o 0.010(0.25) bsc gauge plane |
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