PWM controller for boost, flyback, and forward converters
The TL2842D-8 is a fixed-frequency current-mode PWM controller from Texas Instruments, designed for step-up and step-up/step-down topologies including boost, flyback, and forward converters. It drives an external transistor with a single output and operates at switching frequencies up to 500kHz. The controller supports a wide supply range of 10V to 30V and delivers a maximum duty cycle of 97%, allowing high step-up ratios in flyback designs or wide input-voltage regulation in forward converters. Housed in an 8-SOIC surface-mount package, it is suited for industrial power supplies, telecom DC-DC modules, battery chargers, and auxiliary bias rails where a robust, simple controller is needed without synchronous rectification or clock synchronization.
Switching frequency and duty cycle — what they mean for the transformer
The 500kHz switching ceiling lets you shrink the magnetic components compared to a 100kHz design, but the controller lacks clock sync, so multiple units on the same board will beat unless you add external filtering or spread-spectrum techniques. The 97% duty cycle is a practical max — at high line or light load the controller will skip pulses before hitting that limit, which keeps the output in regulation without saturating the core.
Supply range and temperature grade
The 10V to 30V Vcc range covers standard 12V and 24V industrial buses with headroom for transients. The -40°C to 85°C operating temperature covers indoor and outdoor telecom cabinets, factory floor enclosures, and most commercial equipment — but not extended automotive under-hood or downhole environments.
Active lifecycle — no LTB pressure
Listed as Active with ROHS3 compliance. This part is a standard production item through independent distribution — no supply-chain urgency beyond normal lead times.
Sourcing and fit for the BOM
The TL2842D-8 is a current-production, ROHS3-compliant PWM controller in an 8-SOIC package. For dual-sourcing considerations, the UCC2806DWTR is a functional peer (current-mode, boost/flyback/forward) but carries a 50% duty cycle limit and two outputs — check the pinout and compensation network before substituting.