Multi-topology PWM controller in 16-SOIC wide-body
The Texas Instruments UC3825DW is a current-mode PWM controller that supports step-up, step-down, and step-up/step-down topologies including Buck, Boost, Flyback, Forward Converter, Full-Bridge, Half-Bridge, and Push-Pull — a single part number covers isolated and non-isolated designs across a wide power range. Housed in a 16-SOIC wide-body package (7.50mm width), the controller drives two external MOSFETs via its transistor-driver outputs, making it suited for half-bridge and push-pull stages where complementary gate drive is needed.
340–460 kHz switching with 85% duty ceiling
The switching frequency range of 340 kHz to 460 kHz sets the transformer/inductor sizing and EMI filter corner — a 400 kHz design shrinks magnetics compared to 100 kHz controllers but requires attention to gate-drive layout and snubber design. An 85% maximum duty cycle limits the step-down ratio in a single stage; for high Vout/Vin ratios, a two-stage or transformer-coupled topology is needed.
Control features and temperature grade
Control features include Current Limit, Enable, Frequency Control, Ramp, and Soft Start — the soft-start pin allows programmable inrush current limiting, while the frequency-control pin lets the designer synchronize or adjust the oscillator with an external resistor. The output configuration is positive, with two outputs driving external transistors; no synchronous rectifier is integrated, so the designer must add external FETs and a rectifier stage for high-efficiency designs.
ROHS3 compliant, with no restricted-substance exemptions that would complicate EU or global BOM compliance.