Switching controller for buck and buck-boost rails
The LM3477MM/NOPB is a current-mode PWM controller for step-down (buck) and buck-boost topologies, driving an external transistor switch. Its 500 kHz fixed switching frequency lets the output inductor and capacitor shrink relative to a 100 kHz design, saving board area in a point-of-load rail. The 93 % maximum duty cycle keeps the output in regulation through low headroom — useful when the input sags close to the target output voltage. Operating temperature is rated -40 °C to 125 °C junction, which suits industrial enclosures and under-hood automotive compartments where ambient heat raises the die temperature above 85 °C. The 8-VSSOP package (3.00 mm width) fits tight layouts on multi-layer boards.
Sourcing and compliance status
It is RoHS3 compliant and free of the six restricted substances under EU Directive 2011/65/EU. No pin-compatible second-source or official successor is recorded in the TI portfolio.