LT1777 Datasheet | Linear Technology

LT1777 Low Noise Step-Down Switching Regulator Features s s s s s s s s s DESCRIPTIO Programmable d I/dt Limit Internally Limited d V/dt High Input Voltage: 48V Max 700m A Peak Switch Rating True Current Mode Control 100k Hz Fixed Operating Frequency Synchronizable to 250k Hz Low Supply Current in Shutdown: 30µA Low Thermal Resistance 16-Pin SO Package The LT ®1777 is a Buck (step-down) regulator designed for noise sensitive applications. It contains a d I/dt limiting circuit programmed via a small external inductor in the switching path. Internal circuitry also generates controlled d V/dt ramp rates. The monolithic die includes all oscillator, control and protection circuitry. The part can accept operating input voltages as high as 48V, and contains an output switch rated at 700m A peak current. Current mode control offers excellent dynamic input supply rejection and short-circuit protection. The internal control circuitry is normally powered via the VCC pin, thereby minimizing power drawn directly from the VIN supply (see Applications Information). The fused-lead SO16 package and 100k Hz switching frequency allow for minimal PC board area requirements. , LTC and LT are registered trademarks of Linear Technology Corporation. U APPLICATIO S s s s Automotive Cellular and GPS Receivers Tele Power Supplies Industrial Instrument Power Supplies TYPICAL APPLICATIO Low Noise 5V Step-Down Supply VIN 24V + 10 39µF 63V 100p F 12 14 100p F 12k SGND 2200p F 7 12.1k 1% 1777 TA01 VIN SHDN VCC VSW VD FB LT1777 SYNC VC 4 1µH- 6 5 13 MBRS1100 220µH VOUT 5V 400m A 36.5k 1% VSW VOLTAGE 10V/DIV + 100µF 10V VSW CURRENT 200m A/DIV 1777 TA02 - PROGRAMS d I/d T VSW Switching Waveforms 500ns/DIV...