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adp2441 - evalz user guide ug - 407 one technology way ? p. o . box 9106 ? norwood, ma 02062 - 9106, u.s.a. ? tel: 781.329.4700 ? fax: 781.461.3113 ? www.analog.com adp2441 evaluation board please see the last page for an important warning and legal terms and conditions . rev. 0 | page 1 of 12 features full - featured e valuation board for the adp2441 configurable synchronous step down dc - dc switching regulator operating voltage range of b oard : v in = 6 v to 36 v output v oltage is set to 5 v or can be adjusted maximum l oad 1 a switching frequency set to 500 k hz or a djustable s witching f requency of 300 k hz to 1 mhz power saving mode at light load precision enable input pin current limit protection power g ood output external soft start set to 6 ms or external tracking available board s ize: 53 mm 53 mm documents needed adp2441 d ata sheet ug- 407 general description the adp2441 evaluation b oard is a complete, dc - to - dc s witch - ing regulator design based on the adp2441 , a configurable, 1 a, synchronous step - down, dc - to - dc regulator. the adp2441 is a synchronous, step - down dc - to - dc s witching regulator that uses a current mode pulse - width modulation (pwm) control scheme at medium - to - heavy load currents for high efficiency and s moothly transitions to a pulse skip mode at light loads to conserve power. the power switch and synchronous rectifier are integrated for minimal external part count and high efficiency. the adp2441 is optimized for opera tion with small ferrite core inductors and ceramic capacitors to deliver the maximum output power per square millim eter of the pcb board area. t he adp2441 - e va l z is available with 5 v at 1 a output, swi tching frequency set to 500 khz . if needed, the adp2441 evaluation board configuration can be modified by changing the values of the appropriate passive components . complete specifications for the adp2441 device can be found in the adp2441 data sheet, which is available from analog devices, inc., and should be consulted in conjunction with this user guide when using the evaluation board. adp2441 - evalz figure 1. 10694-101
UG-407 adp2441- evalz user guide rev. 0 | page 2 of 12 table of contents features .............................................................................................. 1 documents needed .......................................................................... 1 general description ......................................................................... 1 adp24 41 - e va l z ............................................................................. 1 revision history ............................................................................... 2 using the evaluation board ............................................................. 3 powering up the evaluation board ............................................ 3 measuring evaluation board performance ............................... 4 modifying the evaluation board .....................................................5 changing the output voltage ......................................................5 changing the switching frequency ............................................5 changing the soft start time ......................................................5 typical performance characteristics ..............................................6 evaluation board schematics and artwork ...................................8 ordering information .................................................................... 10 bill of materials ........................................................................... 10 revision history 6/1 2 initial version: revision 0
adp2441- evalz user guide UG-407 rev. 0 | page 3 of 12 using the evaluation board powering up the evaluation board the adp2441 evaluation board is provided fully assembled and tested. before applying power to the evaluation board, follow the procedures in this section. input power source the power source voltage must not exceed 36 v, the maximum operation input voltage of the ad p2441 . make sure the power source is switched off b efore connecting it to the adp2441 evaluation board . connect the positive terminal of the power source to the eva luation board v in terminal (t1) , and the negative terminal of the power source to the evaluation board gnd terminal (t2). if the power source includes an ammeter, connect the ammeter in series with the input source voltage. connect the positive lead (+) of the power source to the ammeter positive (+) connection, the negative lead (?) of the ammeter to the evaluation board v in terminal (t1), and the negative lead (?) of the p ower source to the evaluation board gnd terminal ( t2 ). output load make sure the evaluation board is switched off before connect - ing the load. c onnect the load directly to the evaluation board, with the positive (+) load connection to the v out terminal (t3) and the negative (?) load connection to the gnd terminal ( t4 ) . if an ammeter i s used, connect it in series with the load: connect the positive (+) ammeter terminal to the evaluation board v out terminal ( t3 ), the negative (?) ammeter terminal to the positive (+) load terminal, and the negative (?) load terminal to the evaluation board gnd terminal ( t4 ). once the load is connected, make sure it is set to the proper current before powering the adp2441 evaluation board. before connecting a load to the output of the evaluation board, make sure that the output voltage does not exceed the maximum operating voltage range of the load. enabling and disabling the dc - to - dc switching regulator in the evaluation board, a voltage divider i s used to generate an enable signal for the ic. as soon as voltage is applied to v in (24 v), ic is enabled. alternatively, header tp1 (en) is available to enable and disable the evaluation board. to enable the output, connect the header tp1 t o the v in sup ply or to an external voltage source. to disable the output connect the header tp1 to the gnd. pgood signals when the output is enabled and the output voltage, v out , is in re gulation, the logic signal at the pgood test point is high. in a typical application, a p ull- up resistor from the pgood p in to the external supply is used to generate this logic signal . on the evaluation b oard, the pull - up resistor ( r7 ) is available to connect to the external supply through the jumper ( jp1 ) . test point tp2 is available to connect the external supply of 5 v. figure 2 pgood signal external ss/track signal the ss/trk pin is multipurpose. it can be used either for tracking the external supply or for soft start. a h eader, t rk , is available on the board for connecting an external signal to be tracked by the regulator output voltage. before applying a signal to the trk header , make sure the voltage divider resistor values ( r10, r11 ) connected on the evaluation board are the correct values (see the adp2441 data sheet) . alternatively, to program soft start time , a capacitor can be connected to ss /trk pi n. o n the evaluation board, a 10 nf capacitor, c11 , is connected for a soft start time of 6 ms . figure 3. soft start signal pgood tp2: externa l supply : 5v jp1 10694-001 r7 50k ? r10 open r11 open c11 10nf ss ss/trk trk 10694-002
UG-407 adp2441- evalz user guide rev. 0 | page 4 of 12 measuring e valuation b oard performance output voltage ripple to observe the output voltage ripple, place an oscilloscope probe tip at terminal t3 and connect the probe ground lead at the negative (?) terminal t4. set the oscilloscope to an ac - coupled, 100 mv/division and 2 s/division time base. switching waveform to observe the switching waveform with an oscilloscope, place the oscilloscope probe tip at the end of the inductor that is connected to the sw pin with the probe ground at terminal t4, gnd. set the scope t o dc, 5 v/division, and 2 s/d ivision time base. the switching wave form should alternate between 0 v and approximately the input voltage. figure 4 . switch node measurement measuring load regulation the load regulation should be measured by increasing the load at the output and looking at the change in output voltage. to minimize voltage drop, use short low - resistance wires, especially for heavy loads. measuring line regulation vary the input voltage and examine the change in the output voltage. in pwm mode , the output vo ltage ripple should be small (< 50 mv) but in pulse skip mode , the output voltage ripple can be as large as 100 m v. measuring efficiency the efficiency, , is measured by comparing the input power with the output p ower. inin out out iv iv = measure the input and output voltages as close as possible to the input and output capacitors to reduce the effect of ir drops. inductor current the inductor current can be measured by removing one end of the inductor from its pad and connecting a current loop in series with it. then a current probe can be used to measure the current flowing through the current loop. line transient response generate a step input voltage (v in ) and observe the behavior of the output voltage, wi th an oscilloscope. load transient response generate a load current transient at the output, v out , and observe the output voltage response with an oscilloscope. use a current probe attached to the wire between the output and the load to visualize the current transient. loop stability measurement closed - loop response can be measured using a network analyzer . to measure the loop response , header i n and header out are available. 10694-104
adp2441- evalz user guide UG-407 rev. 0 | page 5 of 12 modifying the evaluation board the adp2441 evaluation board is provided fully assembled and tested for proper operation. the adp2441 - e va l z has a fixed 5 v output voltage. changing the output voltage the adp2441 - e va l z output regulation voltage is set by a resistive voltage divider consisting of resistors r2 and r3. resistor r2 corresponds to the r top resistor in the data sheet and resistor r3 corresponds to the r bot tom resi stor in the data sheet. the output regulation voltage is determined by the equation ? ? ? ? ? ? + = 3 v6.0 r r3r2 v out where: r2 is the value of the top resistor of the voltage divider ( r top ). r3 is the value of the bottom resistor of the voltage divider (r bot tom ). v out is the output regulation voltage in volts. to set the output regulation voltage to the desired value, first determine the value of the bottom resistor, r3, by string fb i v r3 = where: v fb = 0.6 v, the internal reference. i string is the resistor divider string current (greater than 20 a nominally) . once r3 is determined, calculate the value of the top resis tor, r2 , by ? ? ? ? ? ? ? = fb fb out v vv r3r2 for example, to set the output regulation voltage of adp24 41 - e va l z to 3.3 v, calculate the value of resistors r 2 and r3 as shown in the following equations: k 10 a 60 v 0.6 == = string i fb v r3 k3.45 v6.0 v6.0v3.3 k10 = ? ? ? ? ? ? ? = ? ? ? ? ? ? ? = fb fb out v vv r3r2 note that when the output voltage of adp2441 - e va l z is changed, the output capacitors (c7 and c8), inductor (l1) , and compensation compo nents (r5 and c10) should be re calculated and changed according to the application information section in the adp2441 data sheet to ensure stable operation. table 1 . programming output voltage voltage (v) r2 (k ) r3 (k ) 12 190 10 5 73 10 3.3 45 10 1.2 10 10 changing the switchi ng frequency the switching frequency (f sw ) set point can be changed by replacing resistor r9 with a different value using following equation : sw f r 500,92 9 = w here: r9 is the frequency resistor in k ?. f sw is the switching frequency in kh z. table 2 . programming frequency r9 ( k ) frequency ( kh z) 308 300 1 32 700 92.5 1000 note that when the switching frequency (f sw ) is changed, to ensure stable operation, the values of inductor l1, c7, c8 ( output capacitors ) , and r5, c10 ( compensation components ) must be recalculated and changed (see the a dp2441 data sheet for details on external component selection) . changing the soft start time the soft start time of the adp2441 on the evaluation board is programme d to 6 ms. to change the soft start time, t ss , replace capacitor c11 with a different capacitor value using the following equation : ss ref ss t v i c11 = where: v ref is the internal reference voltage and equals 0.6 v. i ss is the soft start current and equals 1 a. c11 is the soft start capacitor value. t ss is the soft start time
UG-407 adp2441- evalz user guide rev. 0 | page 6 of 12 typical performance characteristics figure 5 . efficiency vs. load current, v out = 5 v , f sw = 500 khz figure 6 . efficiency vs. load current, v out = 3 .3 v, f sw = 500 khz figure 7 . load regulation, v out = 5 v, f sw = 500 khz figure 8 . line regulation , v out = 5 v, f sw = 500 khz figure 9. pulse skip waveform v in = 24 v; v out = 5 v, f sw = 500 khz , no load figure 10 . pwm waveform , v in = 24 v, v out = 5 v, f sw = 500k, load = 1 a 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 efficiency (%) load (a) 10694-004 v in = 12v v in = 24v v in = 36v 0 10 20 30 40 50 60 70 80 90 100 0.01 0.1 1 efficiency (%) load (a) 10694-005 v in = 5v v in = 12v v in = 24v v out (v) 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 load (a) 10694-006 5.001 5.003 5.005 5.007 5.009 5.011 5.013 5.015 v in = 12v v in = 24v v in = 36v v out (v) v in (v) 10694-007 4.985 4.990 4.995 5.000 5.005 5.010 5.015 5.020 8 13 18 23 28 33 38 no load load 1a ch1 100mv ch2 10v m20 s a ch4 150m a 1 4 2 t 46.8% b w ch4 500m a ? vout swsw 10694-008 inductor current ch1 50mv ch2 10v m2s a ch2 7.6v 1 4 2 t 46.8% b w ch4 500ma ? vout inductor current swsw 10694-009
adp2441- evalz user guide UG-407 rev. 0 | page 7 of 12 figure 11 . load transient , v in = 24 v, v out = 5 v, 500 ma step figure 12 . load transient , v in = 12 v , v out = 5 v, 500 ma figure 13 . startup ; v in = 24 v, v out = 5 v, load 5 figure 14 . shutdown; v in = 24 v, v out = 5 v, load 5 figure 15 . bode plot; v in = 24 v, v out = 5 v, f sw = 500 khz , load = 1 a f co = 37 kh z, phase margin = 55 ch1 100mv ch2 10v m200 s a ch4 720m a 1 4 2 t 71.2% b w ch4 500m a ? vout load step 500ma swsw 10694-010 ch1 100mv ch4 500m a m200 s a ch4 800m a 1 4 2 t 71.4% b w ch2 5v ? vout load step 500ma sw 10694-0 11 ch2 2v ch1 2v ch3 2v m2ms a ch2 1.92v 2 1 4 3 t 10.6% b w ch4 500mv enable vout ss pgood 10694-012 ch2 5v ch1 2v ch3 2v m400 s a ch2 1.90v t 50.2% b w ch4 1v 1 4 2 4 enable vout ss pgood 10694-013 200 ?200 160 ?160 120 ?120 80 ?80 40 ?40 0 1 10 1k 10k 100k ?90 90 ?70 70 ?50 50 ?30 30 ?10 10 phase (degrees) magnitude (db) frequenc y (hz) 10694-014
UG-407 adp2441-evalz user guide rev. 0 | page 8 of 12 evaluation board schematics and artwork figure 16. 10694-015
adp2441- evalz user guide UG-407 rev. 0 | page 9 of 12 figure 17 . top layer figure 18 . third layer figure 19 . second layer figure 20 . bottom layer 10694-016 10694-018 10694-017 10694-019
UG-407 adp2441- evalz user guide rev. 0 | page 10 of 12 ordering information bill of materials table 3 . qty reference designator description manufacturer / part number 2 c1, c2 capacitor mlcc, 4.7 f, 50 v,1206, x7r murata grm31cr71h475ka12l 2 c3, c4 capacitor mlcc, 1 f,25 v,0603, x7r murata grm188r71e105ka12d 1 c5 capacitor, mlcc, 10 nf, 50 v,0603, x7r murata grm188r71h103ka01d 2 c7, c8 capacitor, mlcc, 22 f, 25 v 1210, x7r murata grm32er71e226k 1 c11 capacitor 10 nf, 50 v ceramic x7r panasonic ecj - 1vb1h103k 1 l1 mss1038t - 273 coilcraft coilcraft 1 c6 capacitor mlcc, 0.1 f, 50 v, 0603, x7r murata grm188r71h104ka93d 1 c10 capacitor mlcc 270 pf, 50 v,0603, x7r murata 1 r1 resistor, 49.9 , 1/10 w, 1% 0603 smd determined by user 2 r3 , r8 resistor, 10 k , 1/10 w, 1% 0603 smd determined by user 1 r7 resistor, 50 k , 1/10 w, 1% 0603 smd determined by user 1 r2 resistor, 73.2 k , 1/10 w, 1% 0603 smd determined by user 1 r5 resistor, 118 k, 1/10 w, 1% 0603 smd determined by user 1 r6 resistor, 18 2 k , 1/10 w, 1% 0603 smd determined by user 1 r9 resistor, 1 85 k , 1/10 w, 1% 0603 smd determined by user 1 r10 resistor, 0 , 1/10 w, 1% 0603 smd determined by user 1 r11 resistor, open, 1/10 w, 1% 0603 smd determined by user 4 track, ss, in, out headers sullins pbc01saan 4 tp1, tp2, tp3, tp4 headers sullins pbc01saan 1 j p 1 pgood jumper sullins pbc03saan 4 t1, t2, t3, t4 terminal, double turret, brass, 0.078 keystone 1502 - 1 1 u1 adp2441 analog devices adp2441
adp2441- evalz user guide UG-407 rev. 0 | page 11 of 12 notes
UG-407 adp2441-evalz user guide rev. 0 | page 12 of 12 notes esd caution esd (electrostatic discharge) sensitive device . charged devices and circuit boards can discharge without detectio n. although this product features patented or proprietary pr otection circuitry, damage may occur on devices subjected to high energy esd. therefore, proper esd precautions should be taken to avoid performance degradation or loss of functionality. legal terms and conditions by using the evaluation board discussed herein (together with an y tools, components documentation or support materials, the ev aluation board), you are agreeing to be bound by the terms and conditions set forth below (agreement) unless you have purchased the evaluation board, in which case the analog devices standard terms a nd conditions of sale shall govern. do not use the evaluation board until you have read and agreed to the agreement. your use of the evaluation board shall signify your acceptance of the agreement. this a greement is made by and between you (customer) and analog devices, inc. (adi), with its principal place of business at one technology way, norwood, ma 02062, usa. subject to the terms and condition s of the agreement, adi hereby grants to customer a free, limited, personal, temporary, non-exclusive, non-sublicensable, non-transferable license to use the evaluation board for evaluation purposes only. customer understands and agrees that the evaluation board is provided for the sole and exclusive purpose referenced above, and agrees not to use the evaluation board for any other purpose. furthermore, the license granted is expressly made subject to the following additional limitations: customer shall not (i) rent, lease, display, sell, transfer, assign, sublicense, or distribute the evaluation boar d; and (ii) permit any third party to access the evaluation board. as used herein, the term third party includes any entity other than adi, customer, their employees, affiliates and in-house consultants. the evaluatio n board is not sold to customer; all righ ts not expressly granted herein, including ownership of the evaluation board, are reserved by adi. confiden tiality. this agreement and the evaluation board shall all be c onsidered the confidential and propriet ary information of adi. customer may not disclose or transfer any portion of the evaluation board to any other party for any reason. upon discontinuation of use of the evaluation board or termination of this agreement, customer agrees to promptly return the evaluation board to adi. additional restri ctions. customer may not disassemble, decompile or reverse engine er chips on the evaluation board. customer shall inform adi of any occurred damages or any modifications or alterations it makes to the evaluation board, including but not limited to soldering o r any other activity that affects the material content of the evaluation board. modifications to the evaluation board must comply with applicable law, including but not limited to the rohs directive. termina tion. adi may terminate this agreement at any time upon giving written notice to customer. customer agrees to return to adi the evaluation board at that time. limitation of liability. the evaluation board provided hereunder is provided as is and adi makes no warranties or representations of any kind with respect to it. adi specifically disclaims any re presentations, endorsements, gua rantees, or warranties, express or implied, related to the evaluation board including, but not limited to, the implied warranty of merchantability, title, fitness for a particular purpose or noninfringement of intellectual property rights. in no event will adi and its licensors be liable for any incidental, special, indirect, or consequential damag es resulting from customers possession or use of the evaluation board, including but not limited to lost profits, delay costs, labor costs or loss of goodwill. adis total liab ility from any and all causes shall be limited to the amount of one hundred us dollars ($100.00). export. customer agrees that it will not directly or indirectly export the evaluati on board to another country, and that it will comply with all applicable united states federal laws and regulations relating to exports. governing law. this agreement shall be governed by and constru ed in accordance with the substantive laws of the commonwealth of massachusetts (excluding conflict of law rules). any legal action regarding this agreement will be heard in the state or federa l courts having jurisdiction in suffolk county, massachusetts, and customer hereby submits to the personal jurisdiction and venue of such courts. the united nations convention on contracts for the international sale of goods shall not apply to this agreement and is expressly disclaimed. ?2012 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. ug10694-0-6/12(0)

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