深圳市中立信电子科技有限公司

1 Features

1• 8-lead VSSOP-8 and SOIC-8 packages

• Internal Push-Pull Driver With 1-A Peak Current

Capability

• Current Limit and Thermal Shutdown

• Frequency Compensation Optimized With a

Capacitor and a Resistor

• Internal Soft Start

• Current Mode Operation

• Undervoltage Lockout With Hysteresis

• Create a Custom Design Using the LM3478 with

the WEBENCH Power Designer

2 Applications

• Distributed Power Systems

• Battery Chargers

• Offline Power Supplies

• Telecom Power Supplies

• Automotive Power Systems

• Wide Supply Voltage Range of 2.97 V to 40 V

• 100-kHz to 1-MHz Adjustable Clock Frequency

• ±2.5% (Over Temperature) Internal Reference

• 10-μA Shutdown Current (Over Temperature)
3 Description The LM3478 is a versatile Low-Side N-Channel MOSFET controller for switching regulators. It is suitable for use in topologies requiring a low side MOSFET, 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 the LM3478 can be adjusted to any value between 100 kHz and 1 MHz 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 5 μA and allows power supply sequencing. Internal soft-start limits the inrush current at start-up.