general description the max8653 dual-output, synchronous, step-down reg- ulator contains low r ds(on) integrated high-side mosfet switches for ease of layout and achieving small footprints. each output delivers up to 5a. the output voltage is adjustable down to 0.6v and operates from a 9v to 14v input voltage. the max8653 uses a proprietary high-bandwidth, constant-frequency, peak-voltage-mode control architecture and operates at an adjustable switch- ing frequency between 300khz to 1.5mhz. the architec- ture is suitable for use with a wide range of output capacitor technologies such as aluminum electrolytic, poscaps, and ceramic capacitors for flexible design. the simple compensation scheme achieves fast response under both line and load transients. the switching frequency is adjustable using a single external resistor. the output channels operate 180 out- of-phase to reduce the input ripple current, thus reduc- ing the required input capacitance. the high operating frequency minimizes the size of external components. the external reference input (refin) enables imple- mentation of tracking applications such as ddr power supplies. the max8653 utilizes internal digital soft-start and features a lossless (cycle-by-cycle) current sens- ing. it includes adjustable, hiccup-mode current-limit and short-circuit protection for minimum power dissipa- tion under fault conditions. each output contains an enable (en_) input along with a power-good (pok_) signal for easy sequencing. the max8653 is available in a 28-pin, 5mm x 5mm thin qfn package. applications features ? integrated 80m r ds(on) , high-side mosfets ? adjustable hiccup-mode short-circuit current- limit protection ? ?% output accuracy over load, line, and temperature ? 9v to 14v input supply range ? adjustable output down to 0.6v ? digital soft-start reduces inrush supply current ? 300khz to 1.5mhz adjustable switching frequency ? external frequency synchronization ? compatible with ceramic, polymer, and electrolytic capacitors ? 180 out-of-phase operation ? enable and pok for each output ? refin feature for tracking applications ? 28-lead 5mm x 5mm thin qfn package max8653 dual, 5a, 1.5mhz step-down regulator with integrated high-side switches ________________________________________________________________ maxim integrated products 1 ordering information in1 bst1 pok1 lx1 dl1 ilim1 fb1 in2 bst2 pok2 lx2 dl2 ilim2 fb2 osc en1 sync pgnd vl avl agnd refin en2 v+ max8653 input 9v to 14v output 1.5v, 5a output2 3.3v, 2a typical operating circuit xx-xxxx; rev 0; 7/07 + denotes lead-free package. * the max8653 is specified in the extended temperature range. ** ep = exposed pad. part temp range* pin-package pkg code MAX8653ETI+ -40? to +85? 28 thin qfn-ep** (5mm x 5mm) t2855-5 pin configuration appears at end of data sheet. telecom network equipment storage servers ddr memories dsl set-top box cable modem for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim's website at www.maxim-ic.com. preliminary
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