evaluates: max8884y/max8884z max8884 evaluation kit general description the max8884 evaluation kit (ev kit) is a fully assembled and tested pcb that demonstrates the highly integrat - ed max8884y step-down dc-dc converter and dual, 300ma, low-dropout (ldo) linear regulator. the step- down output voltage is pin selectable between 1.2v and 1.8v and provides guaranteed output current of 700ma. dual low-noise ldos are also integrated in the max8884y/max8884z. the max8884 ev kit can also evaluate the max8884z. to evaluate the max8884z, order a free sample along with the ev kit. features s step-down converter pin-selectable output voltage (1.2v/1.8v)2mhz (max8884y) or 4mhz (max8884z) switching frequency low output-voltage ripple 700ma output drive capability simple logic on/off control tiny external components s dual low-noise ldos pin-selectable output voltage (ldo1)low 26v rms (typ) output noise high 65db (typ) psrrguaranteed 300ma output drive capability individual on/off control s tiny external components s low 0.1a shutdown current s 2.7v to 5.5v supply voltage range s thermal shutdown s tiny, 2mm x 2mm x 0.65mm csp package (4x4 grid) s fully assembled and tested ordering information + denotes lead(pb)-free and rohs compliant. component list 19-4905; rev 0; 8/09 part type MAX8884EVKIT+ ev kit designation qty description c1, c3, c5, c6 4 2.2 f f q 10%, 10v x5r ceramic capacitors (0603)murata grm188r61c225k or taiyo yuden lmk107bj225k c2 1 4.7 f f q 10%, 16v x5r ceramic capacitor (0805)murata grm21br61c475k or taiyo yuden emk212bj475k c4 1 0.033 f f q 10%, 16v x5r ceramic capacitor (0402)murata grm155r71c333k ju1?ju4 4 3-pin headerssullins ptc36saan digi-key s1012-36-nd l1 1 2.2 f h, 1.3a, 80m i inductor fdk mipf2520d2r2 (2.5mm 2mm 1mm) l2 1 1 f h, 1.4a, 80m i inductor taiyo yuden ckp2520 1r0m (2.5mm 2mm 1mm) r1 0 not installed, resistor (pcb short) u1 1 step-down dc-dc converter and dual ldo linear regulators (16 csp) maxim max8884yereke+t ? 4 shunts (see table 1)digi-key s900-nd or equiva - lent ? 1 pcb: max8884 evaluation kit+ for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim?s website at www.maximintegrated.com. downloaded from: http:///
2 maxim integrated evaluates: max8884y/max8884z max8884 evaluation kit table 1. jumper function (ju1?ju4) quick start recommended equipment u variable 6v power supply capable of delivering 700ma (referred to as ps1) u one voltmeter u load resistors or electronic loads capable of 700ma procedure the max8884 ev kit is a fully assembled and tested surface-mount pcb. follow the steps below to verify board operation: 1) place the ju1, ju2, and ju3 shunts across pins 1-2 to enable the step-down converter, ldo1, and ldo2 outputs. 2) place the ju4 shunt across pins 1-2 to select 1.8v for the step-down output and 2.8v for the ldo1 output. 3) preset ps1 to 3.6v. turn off the power supply. do not turn on the power supply until all connec - tions are completed. 4) connect the positive lead of the ps1 power supply to the in1 and in2 pad. connect the negative lead of the ps1 power supply to the pgnd pad. 5) turn on the power supply. 6) verify that the voltage is approximately 1.8v at the out pad. 7) verify that the voltage is approximately 2.8v at the ldo1 pad. 8) verify that the voltage is approximately 2.8v at the ldo2 pad. turn off the power supply. 9) change the ju4 shunt from pins 1-2 to pins 2-3 to change the step-down and ldo1 output voltage. turn on the power supply. 10) verify that the voltage is approximately 1.2v at the out pad. 11) verify that the voltage is approximately 1.8v at the ldo1 pad. detailed description of hardware step-down converter the step-down converter delivers 700ma with either 1.2v or 1.8v selectable output voltage using vsel (see table 1). a hysteretic pwm control scheme ensures high efficiency, fast switching, fast-transient response, low- output voltage ripple, and tiny external components. ldo1 and ldo2 dual 300ma low-noise, high-psrr low-dropout regula - tors (ldos) are integrated in the max8884y/max8884z. the ldo1 output voltage is determined by the status of jumper ju4, vsel (see table 1). the ldo2 output volt - age is preset to 2.8v.smaller output capacitors can be used for ldo1 and ldo2 if they are used at less than full-load capability. refer to the max8884y/max8884z ic data sheet for more information. shutdown mode the step-down converter, ldo1, and ldo2 are individu - ally enabled or disabled with jumpers ju2, ju3, and ju1 (table 1). when the step-down and ldos are all in shut down, the max8884y/max8884z enter a very low-power state, where the input current drops to 0.1 f a (typ). component suppliers note: indicate that you are using the max8884 when contacting these component suppliers. supplier phone website digi-key corp. 800-344-4539 www.digikey.com fdk corp. 408-432-8331 www.fdk.co.jp murata electronics north america, inc. 770-436-1300 www.murata-northamerica.com sullins electronics corp. 760-744-0125 www.sullinselectronics.com taiyo yuden 800-348-2496 www.t-yuden.com jumper label shunt position 1-2 2-3 ju1 ldo2_en enable ldo2 disable ldo2 ju2 buck_en enable step- down converter disable step- down converter ju3 ldo1_en enable ldo1 disable ldo1 ju4 vsel v out = 1.8v, v ldo1 = 2.8v v out = 1.2v, v ldo1 = 1.8v downloaded from: http:///
3 maxim integrated evaluates: max8884y/max8884z max8884 evaluation kit figure 1. max8884 ev kit schematic thermal shutdown thermal shutdown limits total power dissipation in the max8884y/max8884z . if the junction tempera - ture exceeds +160 n c, thermal-shutdown circuitry turns off the ic, allowing it to cool. the ic turns on and begins soft-start after the junction temperature cools by +20 n c. this results in a pulsed output during continuous thermal-overload conditions. evaluating the max8884z to evaluate the max8884z, carefully remove the max8884y (u1) and install the max8884z. the inductor l1 also needs to be replaced by the extra inductor (l2) on the ev kit. in1a fb in1b nc2 lx pgnd refbp agnd ldo1ldo2 nc1buck_en sel c4 in1 in1 pgnd c1 2.2 f f c2 4.7 f f l2 1 f h extra inductor for max8884z l1 2.2 f h c32.2 f f c40.033 f f c52.2 f f c62.2 f f r1 pcb short c3 a3 d4d3 b4 a4 a1 a2 d1 b1 b2 c2d2 b3 c1 in2 in2 out agnd ldo1 ldo2 in1 13 2 ju2 buck_en in2 13 2 ju3 ldo1_en ldo1_enldo2_en in2 ju1 ldo2_en in1 13 2 ju4 vsel in2 13 2 max8884y u1 downloaded from: http:///
4 maxim integrated evaluates: max8884y/max8884z max8884 evaluation kit figure 2. max8884 ev kit component placement figure 4. max8884 ev kit pcb layout?bottom layer figure 3. max8884 ev kit pcb layout?top layer 2200mil 2000mil 1.0? 2200mil 2000mil 1.0? 2200mil 2000mil 1.0? 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 specifications without notice at any time. the parametric values (min and max limits) shown in the electrical characteristics table are guaranteed. other parametric values quoted in this data sheet are provided for guidance. maxim integrated 160 rio robles, san jose, ca 95134 usa 1-408-601-1000 5 ? 2009 maxim integrated products, inc. maxim integrated and the maxim integrated logo are trademarks of maxim integrated products, inc. evaluates: max8884y/max8884z max8884 evaluation kit downloaded from: http:///
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