ADP1621

www.DataSheet4U.com Constant-Frequency, Current-Mode Step-Up DC/DC Controller ADP1621 FEATURES 92% efficiency (no sense resistor required) ±1.0% initial accuracy IC supply voltage range: 2.9 V to 5.5 V Power-input voltage as low as 1.0 V Capable of high supply input voltage (>5.5 V) with an external NPN or a resistor VIN UVLO and 35 mA shunt regulator External slope compensation with 1 resistor Programmable operating frequency (100 kHz to 1.5 MHz) with 1 resistor Lossless current sensing for switch-node voltage <30 V Resistor current sensing for switch-node voltage >30 V Synchronizable to external clock Current-mode operation for excellent line and load transient responses 10 μA shutdown current Current limit and thermal overload protection Soft start in 2048 clock cycles TYPICAL APPLICATION CIRCUIT VIN = 3.3V L1 4.7µH D1 C3 1µF 10V C4 0.1µF 10V PIN IN RS 80Ω CS R1 35.7kΩ 1% VOUT = 5V 1A ADP1621 SDSN COMP RCOMP 9.09kΩ CCOMP 1.8nF FREQ GND RFREQ 31.6kΩ 1% AGND C1 = MURATA GRM31CR60J476M COUT3 = SANYO POSCAP 6TPE150M L1 = TOKO FDV0630-4R7M GATE PGND FB M1 COUT1 1µF 10V COUT2 10µF 10V R2 11.5kΩ 1% COUT3 150µF 6.3V ×2 C2 120pF C1 47µF 6.3V M1 = VISHAY Si7882DP D1 = VISHAY SSA33L Figure 1. High Efficiency Output Boost Converter in Lossless Mode, 3.3 V Input, 5 V Output (Bootstrapped) 100 90 80 APPLICATIONS APD bias Portable electronic equipment Isolated dc/dc converter Step-up/step-down dc/dc converter LED driver for laptop computer and navigation system LCD backlighti...