Half-bridge driver with integrated oscillator and watchdog
The MAX13256ATB+T is a half-bridge driver IC from Analog Devices, built with power MOSFET technology and rated for 850 mA per channel in a half-bridge (2) output configuration. It integrates an internal oscillator, a status flag, and a watchdog timer — features that let it drive isolated transformer loads with minimal external timing components while monitoring for fault conditions.
Supply range and on-resistance — what they mean for the transformer drive
The device operates from an 8 V to 36 V supply rail, covering the common industrial and telecom voltage range without an external regulator. Typical on-resistance is 600 mOhm for the low-side FET and 1 Ohm for the high-side FET — the asymmetry means the LS path dissipates less conduction loss, so the dead-time budget should account for the HS FET's higher Rds(on) to avoid shoot-through during the cross-conduction interval.
Protection and monitoring — why the status flag and watchdog matter
Fault protection includes current limiting, over-temperature shutdown, and under-voltage lockout (UVLO) — the UVLO threshold prevents the half-bridge from operating with a rail too low to fully enhance the internal MOSFETs, which would otherwise drive them into the linear region and burn excess power. The watchdog timer and status flag give the system a way to detect a stalled or missing clock and assert a clean shutdown, useful when the driver is the primary clock source for an isolated converter.