4A PWM Step-Down DC-DC for PoL Applications

Ricoh has launched the new RP510, a 4A synchronous buck dc-dc converter with an input voltage range up to 5.5V and an optional fixed or adjustable output voltage range from 0.8V to 3.3V. The RP510 supports power supplies or point-of-load (PoL) converters for microprocessors, FPGAs or DSPs in industrial, automotive and consumer applications.

The device features a range of protection circuits contributing to the safe operation of the application. A Power-Good (PG) output provides a fault signal to the system when the device is not ready for regular operation or when any of the protection circuits or states are active. Typical standby current is 0.35μA for the RP510LxxN, and 0.01μA or less for the RP510LxxG/H/J.

An Under Voltage Lock Out (UVLO) function disables the chip below a minimum input voltage level. The Thermal Shutdown function protects the device during an overload condition and disables it when exceeding a temperature threshold. The Output Over Voltage Detection (OVD) and Under Voltage Detection (UVD) indicate a fault signal when the output voltage is 20% above or below the regular setting value.

With the Over Current protection option, the designer can either select from a latched mode or fold-back version, depending on the application requirements. Latched over current protection shuts down the chip after detecting an excessive high load for a specified time and requires a reboot of the power supply to resume to normal operation after removing the excessive load. The fold-back protection circuit is triggered in a similar way but reduces the switching frequency in order to lower the excessive load current, the circuit will be released automatically after removing the excessive load.

The adjustable Soft Start Time provides a smooth output voltage ramp up, by using an external capacitor. The oscillator frequency is internally fixed at 2.3MHz and the RP510 requires a small inductor of 1mH. RP510 has an operating temperature range of -40 to +85 degrees C and is available in a 3 x 3mm DFN3030-12 package, making it suitable for use on high density boards.