5.5 V, 4 A buck targets automotive point-of-load rails

Diodes Incorporated has introduced the AP61406Q, an automotive-qualified synchronous buck converter designed for point-of-load regulators in systems such as infotainment, instrument clusters, telematics modules, and advanced driver assistance systems. The device supports up to 4 A output current with a maximum input voltage of 5.5 V and is intended for compact, high-efficiency DC-DC conversion in space-constrained automotive electronics.

The AP61406Q includes an I2C 3.0-compatible interface supporting SCL clock rates up to 3.4 MHz. Through I2C, designers can configure operating modes and parameters such as PFM/PWM control behavior, switching frequency selections of 1.0, 1.5, 2.0, or 2.5 MHz, and selectable current settings from 1 A to 4 A. Output voltage can be adjusted in 20 mV increments, and the device can report fault status to support diagnostics and system monitoring.

The converter operates over a 2.3 V to 5.5 V input range and integrates both power MOSFETs, using a 75 mΩ high-side device and a 33 mΩ low-side device. Constant on-time control reduces external component requirements and simplifies compensation while maintaining low output ripple. A multi-function enable input provides mode control, supporting low quiescent current operation specified at 20 µA in fixed PFM mode, as well as PWM mode options for consistent ripple behavior across load conditions.

The AP61406Q also includes a power-good indication function with an internal 5 MΩ pull-up resistor and a ±5% window comparator. Integrated protection features include high-side and low-side current sensing for short-circuit conditions, undervoltage lockout, input overvoltage protection, peak and valley current limiting, and thermal shutdown. A proprietary gate-driver approach is used to reduce switching-node ringing to help limit high-frequency radiated EMI.

The device is offered in a W-QFN1520-8/SWP (Type UX) package intended for high ambient temperature operation. Pricing is listed at $0.24 in 1,000-piece quantities. A standard version, AP61406, is also available for industrial and consumer applications.

Additional product information is available on the Diodes Incorporated website.