preliminary EUP3402 ds3402 ver0.1 sep. 2011 1 dual 1a, 2.25mhz synchronous step-down dc/dc regulator description the EUP3402 is synchronous dual step-down dc-dc converters optimized for battery powered portable applications. it provides two independent output vo ltage rails powered by 1-cell li-ion or 3-cell nimh/nicd batteries. the device is also suitable to operate f rom a standard 3.3v or 5v voltage rail. with an input voltage range of 2.7v to 5.5v the EUP3402 is ideal to power portable applications lik e smart phones, pdas and other portable equipment. the EUP3402 operates at 2.25mhz fixed switching frequency allowing the use of small inductors and capacitors to achieve a small solution size. each o utput supports up to 1a load current, typical .the intern al synchronous switch increases efficiency and elimina tes the need for an external schottky diode. the EUP3402 has a user selectable mode of forced pwm and pfm/pwm mode. the forced pwm mode operation provides the lowest ripple noise and the pfm mode operation provides high efficiency at light loads. the EUP3402 has internal soft start and avoids inru sh current during startup. when shutdown, internal res istor discharges the output capacitor. typical application circuit features high efficiency up to 95% 2.25mhz constant switching frequency dual 1a available load current 45a typical quiescent current 2.7v to 5.5v input voltage range 2 channel 180 degree out of phase operation adjustable output voltage as low as 0.6v no schottky diode required short circuit and thermal protection power good output internal soft start function available in 3mm 3mm tdfn-10 package rohs compliant and 100% lead(pb)-free halogen-free applications ssd module smart phones tablet pc portable media players c/ p, fpga and dsp power plug-in dc/dc modules for routers and switchers figure1.
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