rev. 1.0 december 2007 www.aosmd.com page 1 of 4 AOZ1020-EVA ezbuck 2a simple buck regulator evaluation board note general description the aoz1020 evaluation board is a fully assembled and tested circuit board built with the aoz1020 buck regulator ic. it outputs a preset or adjustable voltage at up to 2a of continuous current. the evaluation board requires an input voltage from 4.5v to 16v. the output voltage is preset and can be adjusted from 0.8v to v in ?.4v the AOZ1020-EVA circuit has features like current limit, short circuit protection, input under voltage lock out, internal soft start and thermal shut down. it operates at a ?ed 500khz switching frequency. the current mode control and integrated internal mosfet minimize component count, board area and total cost. the aoz1020 comes in so-8 packages and is rated over a -40? to +85? ambient temperature range. features 4.5v to 16v operating input voltage range output voltage is preset to 3.3v and adjustable down to 0.8v 2a continuous output current fixed 500khz pwm operation internal soft start cycle-by-cycle current limit short-circuit protection thermal shutdown applications p oint of load dc/dc conversion pcie graphics cards set top boxes d vd drives and hdd lcd panels cable modems t elecom/networking/datacom equipment evaluation board schematic figure 1. lx pg vin vin 5v vout fb pgnd en comp agnd c2, c3 22f ceramic r1 r3 r2 10k? c c r c c6 c4 c1 22f ceramic c5 l1 4.7h aoz1020
a oz1020-eva rev. 1.0 december 2007 www.aosmd.com page 2 of 4 component list notes: 1. for evaluation board with different output voltage, these values might be different. 2. output voltage is set by r1; r1 = . table 1 shows that the value of r1 with typical output voltages. tab le 1. ref designation v alue description manufacturer pa rt number manufacturer c1 22? ceramic cap, 22uf, 25v, 1210, x5r grm32er61e226ke15l murata c2 22? ceramic cap, 22uf, 25v, 1210, x5r grm32er61e226ke15l c3 22? ceramic cap, 22uf, 25v, 1210, x5r grm32er61e226ke15l c4 nu c5 1? ceramic cap, 1uf, 25v, 0603, x5r grm188r61e105ka12d c6 1000pf ceramic cap, 1000pf, 50v, 0603, x7r grm188r71e102k cc (2) 2200pf ceramic cap, 2200pf, 50v, 0603, x7r grm188r71e222k r c (2) 8.5k ? thick film res, 1%, 31.6k, 0603 crcw060385k5fktap dale r1 (1) 31.6k ? thick film res, 1%, 31.6k, 0603 crcw060331k6fktap r2 10k ? thick film res, 1%, 10k, 0603 crcw060310k0fktap r3 10k ? thick film res, 1%, 10k, 0603 crcw060310k0fktap l1 (2) 4.7? inductor, 4.7uh, 2.9a lqh55dn4r7m03 murata u1 aoz1020ai buck regulator ic, 2a, 16v aoz1020ai aos vo (v) r1 (k ? ) 1.2 4.99 1.8 12.7 2.5 21.5 3.3 31.6 5.0 52.3 810v o () + 0.8k ? ---------------------------------- -
a oz1020-eva rev. 1.0 december 2007 www.aosmd.com page 3 of 4 pcb layout figure 1. top silk screen figure 2. top layer figure 3. bottom layer
a oz1020-eva rev. 1.0 december 2007 www.aosmd.com page 4 of 4 quick start guide 1. connect the terminals of load to +v out pins and gnd pins. set load current to between 0a and 2a. 2. connect the dc power supply to +v in pin and gnd pins. set dc power supply voltage to between 4.5v and 16v. 3. connect en pin to +v in or any voltage source which is between 2v and 16v. 4. turn on dc power supply and the evaluation circuit will start. 5. measure input voltage at the +v in pin and gnd pins to eliminate the effect of voltage drop on wire between dc power supply and evaluation board. 6. measure output voltage at the +v out pin and gnd pins to eliminate the effect of voltage drop on wire between load and evaluation board. 7. use an oscilloscope to monitor input ripple voltage right across input capacitor c1. 8. use an oscilloscope to monitor output ripple voltage right across output capacitor c2. as used herein: 1. life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body or (b) support or sustain life, and (c) whose f ailure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a signi?ant injury of the user. 2. a critical component in any component of a life support, device, or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. this data sheet contains preliminary data; supplementary data may be published at a later date. alpha & omega semiconductor reserves the right to make changes at any time without notice. life support policy alpha & omega semiconductor products are not authorized for use as critical components in life support devices or systems.
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