evaluates: max17542g in 5v output-voltage application max17542g 5v output evaluation kit general description the max17542g 5v output ev kit provides a proven design to evaluate the max17542g 5v high-efficiency, high-voltage, synchronous step-down dc-dc converter in a tdfn package. the ev kit generates 5v at load currents up to 1a from a 6v to 42v input supply. the ev kit features a 600khz fixed switching frequency for optimum efficiency and component size. the ev kit features a forced- pwm control scheme that provides constant switching- frequency operation at all load and line conditions. features operates from a 6v to 42v input supply 5v output voltage 1a output current 600khz switching frequency enable /uvlo input resistor-programmable uvlo threshold open-drain reset output overcurrent and overtemperature protection proven pcb layout fully assembled and tested quick start recommended equipment max17542g 5v output ev kit 6v to 42v, 2a dc input power supply load capable of sinking 1a digital voltmeter (dvm) function generator procedure the ev kit is fully assembled and tested. follow the steps below to verify the board operation. caution: do not turn on power supply until all connections are completed. 1) set the power supply at a voltage between 6v and 42v. disable the power supply. 2) connect the positive terminal of the power supply to the vin pcb pad and the negative terminal to the nearest pgnd pcb pad. connect the positive terminal of the 1a load to the vout pcb pad and the negative terminal to the nearest pgnd pcb pad. 3) connect the dvm across the vout pcb pad and the nearest pgnd pcb pad. 4) turn on the dc power supply. 5) enable the load. 6) verify that the dvm displays 5v. to turn-on/off the part from en/uvlo, follow the steps below: 1) connect the power supply to the ev kit and turn on the power supply. set the power supply at a voltage between 6v and 42v. 2) connect the function generator output to the en /uvlo test loop. 3) en/uvlo rising threshold is 1.24v and falling threshold is 1.11v. make sure that the voltage-high and voltage-low levels of the function generator output are greater than 1.24v and less than 1.11v, respectively. 4) while powering down the ev kit, irst disconnect the function generator output from the en/uvlo test loop and then turn off the dc power supply. 19-7661; rev 0; 6/15 ordering information appears at end of data sheet. downloaded from: http:///
maxim integrated 2 www.maximintegrated.com evaluates: max17542g in 5v output-voltage application max17542g 5v output evaluation kit detailed description of hardware the max17542g 5v output ev kit provides a proven design to evaluate the max17542g 5v high-efficiency, high-voltage, synchronous step-down dc-dc converter in a tdfn package. the ev kit generates 5v at load cur - rents up to 1a from a 6v to 42v input supply. the ev kit features a 600khz fixed switching frequency for optimum efficiency and component size. the ev kit features a forced- pwm control scheme that provides constant switching- frequency operation at all load and line conditions. the ev kit includes an en/uvlo pcb pad to enable control of the converter output. an additional reset pcb pad is available for monitoring the open-drain logic output. the vcc pcb pad helps measure the internal ldo voltage. soft-start input (ss) the device utilizes an adjustable soft-start function to limit inrush current during startup. the soft-start time is adjusted by the value of c3, the external capacitor from ss to gnd. to adjust the soft-start time, determine c3 using the following formula: c3 = 5.55 x t ss where t ss is the required soft-start time in milliseconds and c3 is in nanofarads. regulator enable/undervoltage-lockout level (en/uvlo) the device features an en/uvlo input. for normal operation, no shunts should be installed across pins 1-2 or 2-3 on jumper ju1. to disable the output, install a shunt across pins 2-3 on ju1 and the en/uvlo pin is pulled to gnd. see table 1 for ju1 settings. setting the undervoltage-lockout level the device offers an adjustable input undervoltage- lockout level. set the voltage at which the device turns on with a resistive voltage-divider connected from vin to gnd (see figure 1 ). connect the center node of the divider to en/uvlo. choose r1 to be 3.3m and then calculate r2 as follows: inu r1 1.218 r2 (v 1.218) = ? where v inu is the voltage at which the device is required to turn on. ensure that v inu is higher than 0.8 x v out . adjusting the output voltage the device offers an adjustable output voltage. set the output voltage with a resistive voltage-divider connected from the positive terminal of the output capacitor (v out ) to gnd (see schematic attached to this pdf). connect the center node of the voltage-divider to fb. to choose the values of r4 and r5, select the parallel combination of r4 and r5, with r p less than 15k. once r p is selected, calculate r4 as follows: p out rv r4 0.9 = calculate r5 as follows: out r4 0.9 r5 (v 0.9) = ? table 1. regulator enable (en/uvlo) jumper ju1 settings *default position. shunt position ev/uvlo pin max17542g 5v output not installed* connected to the center node of resistor-divider r1 and r2 enabled, uvlo level set through the r1 and r2 resistor-divider 2-3 connected to gnd disabled downloaded from: http:///
maxim integrated 3 www.maximintegrated.com evaluates: max17542g in 5v output-voltage application max17542g 5v output evaluation kit figure 1. max17542g 5v output load and line regulation figure 2. max17542g 5v output efficiency 4.90 4.92 4.94 4.96 4.98 5.00 5.02 5.04 5.06 5.08 5.10 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 output voltage (v) load current (a) 5 v output, pwm mode, load and line regulation v in = 36v v in = 24v v in = 12v 60 70 80 90 100 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 efficiency (%) load current (a) 5v output, pwm mode, efficiency vs. load current v in = 36v v in = 24v v in = 12v figure 3. max17542g 5v output 500ma to 1a load transient figure 4. max17542g 5v output no-load to 500ma load transient 40 s /div 100 mv/div 5v o utput, pwm mode, (lo ad curr ent st epped from 0.5 to 1a) v out i out (ac) 500 ma/div 40 s /div 100 mv/div 5v o utput, pwm mode, (lo ad curr ent st epped from 0a to 0.5a) v out (ac) 200 ma/div i out ev kit performance report downloaded from: http:///
maxim integrated 4 www.maximintegrated.com evaluates: max17542g in 5v output-voltage application max17542g 5v output evaluation kit bode plot gain ph as e () frequency(hz) f cr = 60.2khz, ph as e margin = 56.7 v out = 5v gain phase figure 5. max17542g 5v output full-load bode plot (v in = 24v) figure 6. max17542g 5v output ev kit component placement guidecomponent side figure 7. max17542g 5v output ev kit pcb layout component side 1 2 1 2 1 2 1 2 3 1 2 1 2 1 2 1 2 1 1 1 1 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 1 2 1.0 1 2 1 2 1 2 1 2 3 1 2 1 2 1 2 1 2 1 1 1 1 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 1 2 3 4 5 6 7 8 9 10 11 12 13 1 2 1 2 1.0 figure 8. max17542g 5v output ev kit pcb layoutsolder side 1 2 3 1 2 1 2 1 2 1 2 1 1 1 1 1 2 1 2 1 2 1 2 1 2 11 1.0 ev kit performance report (continued) downloaded from: http:///
maxim integrated 5 www.maximintegrated.com evaluates: max17542g in 5v output-voltage application max17542g 5v output evaluation kit figure 9. max17542g 5v output ev kit component placement guidetop solder mask figure 10. max17542g 5v output ev kit component placement guidebottom solder mask #denotes rohs compliant. 1.0 1.0 part type MAX17542GTBEVKIT# ev kit ordering information note: indicate that you are using the max17542g when contacting these component suppliers. supplier website coilcraft, inc. www.coilcraft.com murata americas www.murata.com panasonic corp. www.panasonic.com tdk corp. ww.tdk.com component suppliers component information and schematic see the following links for component information and schematic: max17542g 5v ev bom max17542g 5v ev schematic ev kit performance report (continued) downloaded from: http:///
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. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. ? 2015 maxim integrated products, inc. 6 evaluates: max17542g in 5v output-voltage application max17542g 5v output evaluation kit revision number revision date description pages changed 0 6/15 initial release 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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reference des cr ip i on quan i ty desi gn ator part number 1 2.2 f 10 %, 50 v x7r ceramic c apa citor (1210 ) 1 c1 tdk c 3225 x7r1h 225 k 2 1 f 10 %, 6.3v x7r ceramic c apa citor (0603 ) 1 c2 murata g rm 188 r 70 j 105 k 3 3300 pf 10 %, 50 v x7r ceramic c apa citor (0402 ) 1 c3 murata g rm 155 r 71 h 332 k 4 10 uf 10 %, 10 v x7r ceramic c apa citor (1210 ) 1 c4 murata g rm 32d r 71 a 106 k 5 4700 pf 10 %, 25 v x7r ceramic c apa citor (0402 ) 1 c5 murata g rm 155 r 71 e 472 k 6 33 uf 50 v alumi nu m electroly i c (d =6.3 mm ) 1 c7 p ana sonic eee -fk1h 330 xp 7 27 pf 5%, 50 v c0g ceramic c apa citor (0402 ) 1 c9 murata g rm 1555 c1h 270 j 8 3 -p in he ad er (36 -p in he ad er 0.1 centers ) 1 ju1 su lli ns: ptc 36s aan 9 22 uh i ndu ctor (5 .3 mm x 5.5 mm x 5.1 mm ) 1 l1 co il cra t xal 5050 - 22 3 10 3. 32 m ohm 1%, resistor (0402 ) 1 r1 11 681 k ohm 1%, resistor (0402 ) 1 r2 12 16 .5k ohm 1%, resistor (0402 ) 1 r3 13 82 .5k ohm 1%, resistor (0402 ) 1 r4 14 18 .2k ohm 1%, resistor (0402 ) 1 r5 15 10 k ohm 1%, resistor (0402 ) 1 r6 16 not insta ll ed, op en (0402 ) 0 r7 17 buck converter (10 t df n 3 mm x2 mm ) max 17542 gatb+ 1 u1 max 17542 gatb+ 18 s hun t 1 see jumper table su ll ins stc 02s yan jumper shunt position ju1 1-2 jumper table bill of materials (bom) 6/15 revision downloaded from: http:///
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