US semiconductor manufacturer Diodes has introduced four new automotive-compliant asynchronous buck converters for 48 V low-voltage rail point-of-load applications.

The AP68255Q/AP68355Q and AP6A255Q/AP6A355Q incorporate 500 mΩ power MOSFETs to deliver high-efficiency step-down DC-DC conversion and up to 3.5 A of continuous output current. The converters cover the full automotive battery range from 5.5 V to 80 V/100 V, including load dump scenarios. They can be used in applications including 48 V motor control, advanced driver assistance systems (ADAS), telematics, infotainment, body control, instrument clusters and lighting systems.

The buck converters employ constant on-time (COT) control to maintain a nearly constant switching frequency of 300 kHz. This technique results in fast load/line transient response, easy loop stabilization and low output voltage ripple, according to the company, making it easier to incorporate the devices by requiring fewer external components.

The gate-driver arrangement in the devices reduces switch node ringing effects without sacrificing the turn-on and turn-off times of the N-channel MOSFET switch. This is designed to help reduce the high-frequency radiated electromagnetic interference noise typically associated with MOSFET switching.

The AP68255Q/355Q and AP6A255Q/355Q asynchronous buck converters are available in the thermally enhanced SO-8EP package and support an operating temperature range of -40° C to 125° C.

Built-in overcurrent protection (OCP) incorporating a frequency foldback mode provides high load-current support while reducing junction temperature under fault conditions. The overtemperature protection (OTP) circuit immediately shuts down the controller’s output voltage at 160° C. The converter automatically restarts when the temperature drops below the 140° C safety threshold to prevent controller damage or malfunction.

Source: Diodes