LM3478

LM3478 High Efficiency Low-Side N-Channel Controller for Switching Regulator May 2003 LM3478 High Efficiency Low-Side N-Channel Controller for Switching Regulator General Description The LM3478 is a versatile Low-Side N-FET switching regulator controller. It is suitable for use in topologies requiring low side FET, such as boost, flyback, SEPIC, etc. Moreover, the LM3478 can be operated at extremely high switching frequency in order to reduce the overall solution size. The switching frequency of LM3478 can be adjusted to any value between 100kHz and 1MHz by using a single external resistor. Current mode control provides superior bandwidth and transient response, besides cycle-by-cycle current limiting. Output current can be programmed with a single external resistor. The LM3478 has built in features such as thermal shutdown, short-circuit protection, over voltage protection, etc. Power saving shutdown mode reduces the total supply current to 5µA and allows power supply sequencing. Internal soft-start limits the inrush current at start-up. n 10µA shutdown current (over temperature) Features 8-lead Mini-SO8 (MSOP-8) package Internal push-pull driver with 1A peak current capability Current limit and thermal shutdown Frequency compensation optimized with a capacitor and a resistor n Internal softstart n Current Mode Operation n Undervoltage Lockout with hysteresis n n n n Applications n n n n n Distributed Power Systems Battery Chargers Offline Power Supplies Telecom Power Su...