EUP3427 ds3427 ver1.0 jul. 2011 1 4a, synchronous step-down converter description the EUP3427 is a 1 mhz fixed frequency synchronous, current-mode, step-down dc-dc converter capable of providing up to 4a output current. the EUP3427 operates from an input range of 2.7v to 5.5v and provides a regulated output voltage from 0.6v to 5v . the internal synchronous power switch improves efficiency and eliminates the need for an external schottky diode. the EUP3427 can be externally set f or either forced pwm continuous mode or pulse skipping mode. forced pwm operation provides very low output ripple voltage for noise sensitive applications whi le pulse skipping operation improves light load effici ency by reducing switching loss. the EUP3427 features short circuit and thermal protection circuits to improve system reliability. internally soft-start avoids input inrush current d uring startup. the EUP3427 is available in sop-8 package with the exposed pad and tdfn-10 package. typical application circuit features 2.7v to 5.5v input voltage range high efficiency up to 96% 4a available load current 57/35m integrated pfet/nfet switches 1mhz switching frequency 100% duty cycle low dropout operation short circuit and thermal protection integrated uvlo and power good excellent line and load transient response available in sop-8 (ep) and tdfn-10 packages rohs compliant and 100% lead(pb)-free halogen-free applications high performance dsps, fpgas, asics and microprocessors base station, telecom, and networking equipment power supplies epc and netpcs figure1. sop-8(ep) typical application circuit
EUP3427 ds3427 ver1.0 jul. 2011 2 typical application circuit (continued) figure2. tdfn-10 typical application circuit pin configurations package type pin configurations package type pin configurations sop-8 (ep) tdfn-10 pin description pin sop-8 (ep) tdfn-10 description lx 1 2,3 switch node connected to inductor. this pin is conn ected to the drains of the internal main and synchronous power mosfet switches . skip 2 7 operation mode select input. logic high selects pul se skipping mode, and logic low or floating chooses forced pwm mode. an i nternal 5 a current pull it down to ground. en 3 5 chip enable pin. forcing this pin above 1.5v enable s the part. forcing this pin below 0.3v or floating it shuts down the device.an internal 600k resistor pulls it down to ground. pg 4 4 power good output signal. logic high when regulator output is within 10% of target output voltage. a pull-up resistor of 10k to 100k is recommended for most applications. agnd 5 - analog ground. fb 6 6 feedback pin. connect it to an external resi stor divider to set output voltage. pvin 7 9,10 power supply input. pgnd 8 - power ground. svin - 8 analog input supply which is connected to pvin through a low pass rc filter. nc - 1 no connect. thermal pad - - ground.( thermal pad must be connected to the g round of pcb.)
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