general description the max745 evaluation kit (ev kit) is an assembled and tested pc board that implements a step-down, switch- ing power supply designed for charging lithium-ion (li- ion) batteries. the output voltage can be set for one to four cells. the cell voltage can be set between 4.0v and 4.4v, with 0.75% accuracy, using standard 1% resistors. two leds indicate the charging status. the max745 should be used to charge only li-ion bat- tery packs. to charge other types of batteries, use the max1648 or the max712/max713. to charge smbus smart-battery packs, use the max1645/max1647/ max1667. features charges one to four li-ion cells low heat/high efficiency 300khz pwm operation 0.75% overall accuracy over temperature 6v to 24v input voltage range proven pc board layout fully assembled and tested evaluates: max745 max745 evaluation kit ________________________________________________________________ maxim integrated products 1 designation qty description c1 1 68f, 20v, 0.150 ? , low-esr tantalum capacitor avx tpse686m020r0150 c2, c7, c9, c12 4 0.1f ceramic capacitors c3 1 47nf ceramic capacitor c4 1 0.22f ceramic capacitor c5 1 4.7f ceramic capacitor tdk c2012x5r0j475k murata grm21br60j475m c6 0 open c8, c10 2 150f, 35v, 0.17 ? , aluminum electrolytic capacitors sanyo 35cv150gx ordering information 19-2967; rev 3; 9/03 for pricing, delivery, and ordering information, please contact maxim/dallas direct! at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. part temp range board type MAX745EVKIT 0 c to +70 c surface mount supplier* phone fax avx 803-946-0690 803-626-3123 dale-vishay 402-564-3131 402-563-6418 international rectifier 310-322-3331 310-322-3377 irc 512-992-7900 512-992-3377 kemet 864-963-6300 864-963-6322 motorola 602-303-5454 602-996-6430 murata 770-436-1300 770-436-3030 sanyo 619-661-6835 619-661-1055 sumida 847-956-6835 847-956-0702 tdk 847-803-6100 847-390-4405 component suppliers * please indicate that you are using the max745 when contact- ing these component suppliers. designation qty description c11 1 1000pf ceramic capacitor d1, d4, d6 3 3a, 40v, surface-mount schottky diodes motorola mbrs340t3 d2 1 1n4148-type signal diode (sot23) j3, j4 2 banana jacks ju1, ju2, ju3 3 3-pin headers ju4 1 2-pin header l1 1 22h, 2.8a surface-mount inductor sumida cdrh125-220 led1, led2 2 light-emitting diodes m1 1 2a, 30v, 0.080 ? , logic-level, dual, n-channel fet international rectifier irf7303 component list smbus is a trademark of intel corp.
evaluates: max745 _________________________quick start do not turn on power until all connections are com- plete. observe all precautions on the battery manu- facturer? data sheet. use only lithium-ion (li-ion) cells with this charger. 1) set jumpers ju1 and ju2 to indicate the number of cells in the battery pack (table 1). 2) set jumper ju3 to the 2a position to enable 2a out- put current (table 2). 3) make sure that jumper ju4 is open to enable charger output. 4) connect a dc power supply with sufficient power rating across the vin and gnd banana jacks (vin is positive, gnd is negative). dc input voltage should be between 6v and 24v. 5) connect a li-ion battery pack between batt and gnd (batt is positive, gnd is negative). the bat- tery can be connected with the charger off without causing damage, or it can be connected after power is applied. 6) turn on the dc power supply. fast charging begins as soon as the battery is connected and the dc power supply is on. 7) when the status led turns on, the charger is operating in current-regulating mode (fast charge). when the status led turns off, the charger is operating in voltage-regulating mode (float charge). 8) when the done led turns on, the charging current has fallen below the threshold set by r13, indicat- ing that charging is over. the charger can be shut down by closing jumper ju4. _______________detailed description upon insertion, batteries are fast charged at a constant current. batteries enter float charge when the total bat- tery terminal voltage reaches the voltage limit. led2 (status) indicates that the charger is in current- regulating mode. this signal can be used to detect the transition from fast charge to float charge. led1 (done) indicates that the battery current (fast charge) is below the 1.6a threshold set by r13 = 8k ? . the ibat output pin sources a current that is propor- tional to the load current, and comparator u2 detects when that load current exceeds 1.182v. r13 should not cause the ibat voltage to exceed 2v under maximum load current. refer to the max745 data sheet. max745 evaluation kit 2 _______________________________________________________________________________________ number of cells voltage adjustmant range ju1 position ju2 position 1 4v 4.4v 1, 2 1, 3 28v 8.8v 1, 2 2, 4 3 12v 13.2v 3, 4 1, 3 4 16v 17.6v 3, 4 2, 4 table 1. configuring number of li-ion cells designation qty description r1 1 0.100 ? 1% sense resistor dale wsl-2010-r1f or irc lr2010-01-r100f r2, r15 2 10k ? 5% surface-mount resistors r3, r11, r12, r16 4 100k ? 1% surface-mount resistors r4, r5, r10 0 shorted r6, r7 2 1k ? 5%, surface-mount resistors r13 1 8k ? 5%, surface-mount resistor r14 1 24 ? 5%, surface-mount resistor u1 1 maxim max745eap u2 1 maxim max931csa component list (continued) jumper state function ju1 3, 4 c e ll1 = v l; thr ee or four cel l s sel ected . ju1 1, 2 c e ll1 = gn d ; one or tw o cel l s sel ected . ju2 2, 4 c e ll0 = v l; tw o or four cel l s sel ected . ju2 1, 3 c e ll0 = gn d ; one or thr ee cel l s sel ected . ju3 2a is e t = re f; outp ut cur r ent l i m i ted to 2a. ju3 open is e t i s op en; outp ut cur r ent l i m i ted to 1a. ju3 0a is e t = g n d ; outp ut cur r ent d i sab l ed . ju4 open th m = re f; outp ut enab l ed . ju4 closed th m = g n d ; outp ut enab l ed . table 2. jumper functions
evaluates: max745 max745 evaluation kit _______________________________________________________________________________________ 3 batt cs pgnd dlo lx bst dcin c7 0.1 f c11 1000pf c1 68 f 20v c8 150 f 35v c10 150 f 35v c3 47nf r13 8k ? r14 24 ? r4 short j3 red j4 black r1 0.1 ? 1% r5 short r10 short c12 0.1 f c9 0.1 f c2 0.1 f c5 4.7 f 6.3v c6 open r15 10k ? ju4 r2 10k ? r7 1k ? c4 0.22 f dhi status cello cell1 ref thm/shdn cci ccv dcin ibat vl v- out v+ gnd dcin ref led1 done vin in- in+ hyst vadj seti gnd 7 6 5 r16 100k ? 1% r6 1k ? r3 100k ? 1% r12 100k ? 1% r11 100k ? 1% pgnd ref vl ju3 ju2 ju1 ref vl 4 2 1 3 8 9 10 14 15 16 17 19 20 18 batt+ batt- d1 m1a m1b d4 1 8 7 2 3 6 5 4 d6 l1 22 h 13 12 2a 0a 1a 2, 4 1, 3 3, 4 1, 2 11 max745 u1 max931 u2 pgnd pgnd pgnd d2 vl vl vl 6 4 3 ibat 5 8 7 1 2 vl led2 status vl pgnd gnd figure 1. max745 ev kit schematic diagram
evaluates: max745 max745 evaluation kit 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. 4 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ? 2003 maxim integrated products printed usa is a registered trademark of maxim integrated products. figure 2. max745 ev kit component placement guide component side 1.0" figure 3. max745 ev kit pc board layout?omponent side 1.0" figure 4. max745 ev kit pc board layout?older side 1.0"
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