general description the max1556 evaluation kit (ev kit) is a fully assembled and tested circuit board that evaluates the max1556 and max1557 pwm step-down dc-dc converters. the circuit operates from 2.6v to 5.5v. the max1556 deliv- ers up to 1.2a and has pin-selectable 1.8v, 2.5v, 3.3v, and adjustable output. the max1557 delivers up to 600ma and has pin-selectable 1v, 1.3v, 1.5v, and adjustable output. each circuit features an on-board shutdown control. features ? up to 97% efficiency ? 95% efficiency at 1ma load current ? 1mhz pwm switching frequency ? tiny inductors ? pin-selectable output voltages max1556: 3.3v, 2.5v, 1.8v, and adjustable max1557: 1.5v, 1.3v, 1.0v, and adjustable ? 1.2a guaranteed output current (max1556) ? voltage positioning optimizes load-transient response ? low 16a quiescent current ? low 27a quiescent current in dropout ? low 0.1a shutdown current ? analog soft-start with zero overshoot current ? small, 10-pin, 3mm x 3mm tdfn package ? fully assembled and tested evaluates: max1556/max1557 max1556 evaluation kit ________________________________________________________________ maxim integrated products 1 19-3415; rev 0; 9/04 component list 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. ordering information component suppliers note: indicate that you are using the max1556 when contacting these component suppliers. * ep = exposed paddle. designation qty description c1, c6 2 10? 10%, 6.3v x5r ceramic capacitors (0805) murata grm21br60j106k or equivalent c2, c7 2 22? 10%, 6.3v x5r ceramic capacitors (1206) murata grm31cr60j226k or equivalent c3, c8 0 not installed, capacitors (0805) c4, c9 2 0.001? 10%, 50v x7r ceramic capacitors (0402) murata grp155r71h102k or equivalent c5, c10 0 not installed, capacitors (0603) c11 1 0.47? 10%, 6.3v x5r ceramic capacitor (0402) murata grm155r60j474k or equivalent ju1?u6 6 3-pin headers l1 1 3.3? inductor, 0.036 ? , 1.3a, 5.0mm x 5.0mm x 2.0mm taiyo yuden lmnp04sb3r3n l2 1 4.7? inductor, 0.05 ? , 1.2a, 5.0mm x 5.0mm x 2.0mm taiyo yuden lmnp04sb4r7n r1, r3 0 shorted on pc board, resistors (0603) r2, r4 0 not installed, resistors (0603) r5 1 100 ? ?% resistor (0402) u1 1 max1556etb u2 1 max1557etb none 6 shunts, position 2 none 1 max1556 ev kit pc board supplier phone website murata 814-237-1431 www.murata.com taiyo yuden 408-573-4150 www.t-yuden.com vishay 402-563-6866 www.vishay.com part temp range ic package MAX1556EVKIT 0 c to +70 c 10 tdfn-ep* quick start recommended equipment one variable dc power supply capable of supply- ing up to 5.5v at 1.2a one voltmeter (dmm)
procedure (max1556etb) the max1556 ev kit is fully assembled and tested. follow the steps below to verify board operation: 1) select the desired output voltage with ju1, ju2, and ju3 (see table 1). the ev kit is preset to a 1.8v output. 2) connect the positive terminal of the voltmeter to the pad labeled out. connect the ground terminal of the voltmeter to the pad labeled gnd nearest the out pad. connect a load from out to the gnd pad closest to out. 3) preset the power supply to between 2.6v and 5.5v, and turn the power supply off. do not turn on the power supply until all connections are completed. 4) connect the positive power-supply terminal to the pad labeled in. connect the power-supply ground to the pad labeled gnd nearest the in pad. 5) turn on the power supply and verify the output volt- age is the desired voltage from setting ju1, ju2, and ju3 (default is 1.8v). procedure (max1557etb) the max1556 ev kit is fully assembled and tested. follow the steps below to verify board operation: 1) select the desired output voltage with ju4, ju5, and ju6 (see table 2). the ev kit is preset to a 1.0v output. 2) connect the positive terminal of the voltmeter to the pad labeled out2. connect the ground terminal of the voltmeter to the pad labeled gnd2 nearest the out2 pad. connect a load from out2 to the gnd2 pad closest to out2. 3) preset the power supply to between 2.6v and 5.5v, and turn the power supply off. do not turn on the power supply until all connections are completed. 4) connect the positive power-supply terminal to the pad labeled in2. connect the power-supply ground to the pad labeled gnd2 nearest the in2 pad. 5) turn on the power supply and verify the output volt- age is the desired voltage from setting ju4, ju5, and ju6 (default is 1.0v). detailed description the max1556 ev kit contains two separate pwm step- down dc-dc converter circuits. either circuit can be powered from a dc power supply with a 2.6v to 5.5v input range. the top and bottom circuit are separate from each other and do not share a common ground plane. the top circuit (max1556) provides pin-selectable out- put voltages of 3.3v, 2.5v, 1.8v, and adjustable at 1.2a. the bottom circuit (max1557) provides pin-selectable output voltages of 1.5v, 1.3v, 1.0v, and adjustable at 600ma. pin-selectable output voltages the max1556 output voltage is selected with ju1 and ju2, as shown in table 1. the max1557 output voltage is selected with ju4 and ju5, as shown in table 2. evaluating other output voltages the max1556 ev kit comes with the max1556 preset to a 1.8v output and the max1557 preset to a 1v output. to evaluate other voltages besides the preset values, set the max1556 (or max1557) to adjustable mode. the footprints for the feedback resistors are available on the backside of the evaluation kit. refer to the adjusting the output voltage section in the max1556 data sheet for a detailed description on calculating these feedback resistor values for the desired output voltage. resistor r1 for the max1556 circuit (r3 on max1557) is shorted on the evaluation kit. this short must be cut prior to the placement of a resistor on the footprint. resistor r2 for the max1556 circuit (r4 for max1557) is open and requires no modification before placing a resistor on the footprint. evaluates: max1556/max1557 max1556 evaluation kit 2 _______________________________________________________________________________________ ju1 ju2 ju3 max1556 v out 1 and 2 1 and 2 1 and 2 1.8v 1 and 2 2 and 3 1 and 2 2.5v 2 and 3 1 and 2 1 and 2 3.3v 2 and 3 2 and 3 1 and 2 adj 2 and 3 shutdown table 1. output voltage selection (max1556etb) note: default configuration is ju1, ju2, and ju3 (1 and 2).
external shutdown control the max1556 ev kit comes preset with shdn and shdn2 pulled high so that the max1556 and max1557 are enabled when the input voltage is applied. to operate the shutdown control from an external signal, remove the shunt on ju3 for the max1556 (ju6 for the max1557). apply a logic high to shdn to enable the max1556, or apply a logic low to shut down the max1556. apply a logic high to shdn2 to enable the max1557, or apply a logic low to shut down the max1557. evaluates: max1556/max1557 max1556 evaluation kit _______________________________________________________________________________________ 3 ju4 ju5 ju6 max1557 v out 1 and 2 1 and 2 1 and 2 1.0v 1 and 2 2 and 3 1 and 2 1.3v 2 and 3 1 and 2 1 and 2 1.5v 2 and 3 2 and 3 1 and 2 adj 2 and 3 shutdown table 2. output voltage selection (max1557etb) note: default configuration is ju4, ju5, and ju6 (1 and 2). figure 1a. max1556 ev kit schematic (max1556) u1 max1556 8 9 10 1 2 ju1 3 1 2 ju3 3 1 lx in_p in d1 7 pgnd 4 out 3 ss c2 22 f c1 10 f c11 0.47 f c4 0.001 f exposed pad connected to gnd c3 open r1 short r2 open c5 open out in shdn gnd gnd gnd 5 shdn 1 2 ju2 3 6 2 d2 l1 3.3 h r5 100 ?
evaluates: max1556/max1557 max1556 evaluation kit 4 _______________________________________________________________________________________ figure 1b. max1556 ev kit schematic (max1557) u2 max1557 8 9 1 10 1 2 ju4 3 1 2 ju6 3 lx in_p in d1 7 pgnd 4 out 3 ss c7 22 f c6 10 f c9 0.001 f exposed pad connected to gnd c8 open r3 short r4 open c10 open out2 in2 shdn2 gnd2 gnd gnd2 5 shdn 1 2 ju5 3 6 2 d2 l2 4.7 h
evaluates: max1556/max1557 max1556 evaluation kit _______________________________________________________________________________________ 5 figure 2. max1556 ev kit component placement guide?omponent side figure 3. max1556 ev kit component placement guide?older side
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. 6 _____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2004 maxim integrated products printed usa is a registered trademark of maxim integrated products. evaluates: max1556/max1557 max1556 evaluation kit figure 4. max1556 ev kit pc board layout?omponent side figure 5. max1556 ev kit pc board layout?older side
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