Secondary-side SR controller for efficiency-critical PSUs
The NXP TEA1892TS/1H is a GreenChip™ secondary-side controller designed for synchronous rectification in flyback and resonant power supplies. It replaces a Schottky diode with a low-RDS(on) MOSFET to cut rectifier losses, targeting the 8.5 V to 38 V output rail range typical of adapters, chargers, and auxiliary supplies. The controller draws 1 mA supply current, keeping its own dissipation negligible in the overall efficiency budget. The -40°C to 150°C operating range covers automotive under-hood and industrial environments where the secondary side sees high ambient heat.
Supply rail and thermal design-in
The 8.5 V to 38 V supply range means the controller can be biased directly from the output rail in most designs — no separate auxiliary winding needed. At the low end, 8.5 V leaves headroom for the gate drive of a standard-threshold SR MOSFET. The 1 mA quiescent current is the total IC draw; the actual gate-drive current pulses during switching, so size the VCC decoupling cap for those transients. That 150°C ceiling is common for automotive-grade secondary controllers; it lets the part sit next to the transformer winding where ambient can hit 105°C–125°C. The SC-74 package has a modest thermal footprint — ensure the PCB copper area under the part is adequate for the gate-drive power dissipation at high switching frequencies.
Lifecycle and compliance
There is no successor part to plan for; this is the version to qualify into new designs. ROHS3 compliance is confirmed, so it meets the EU RoHS exemption-free standard for lead-free assembly.