Active current-mode PWM controller for boost and flyback designs
The UCC3813DTR-3: Switching at 31 kHz, the controller sets the transformer core size and the EMI filter corner frequency — a 31 kHz fundamental means the filter design starts attenuating above the switching band, not below it. The 99% maximum duty cycle allows the controller to maintain regulation with very little headroom between the input rail and the output — useful in boost converters where the input voltage dips close to the target output.
Supply range, temperature grade, and package fit
Operating from a 3.6 V to 12 V supply, the UCC3813DTR-3 can be biased from a regulated 5 V rail or directly from a 12 V auxiliary winding on the transformer — no extra linear regulator needed for the controller supply. Housed in an 8-SOIC package, the controller uses a standard footprint with no exposed thermal pad — reflow profile is straightforward, and the package is compatible with automated optical inspection.
The UCC3813DTR-3 is ROHS3 compliant, covering the full RoHS exemption list without time-limited exemptions — no compliance gap for EU or UKCA markets. Sourced against an RFQ through independent distribution.