The devices are intended for applications requiring extended battery life, and reduced mounting area and weight on high density boards.
Today’s wearable and IoT devices mainly operate in a sleep mode and therefore power consumption is significantly defined by the quiescent current, referring to a circuit’s quiet state, not driving any load. In this mode, the system is idle but ready to wake up at any time to perform a task, transmitting some data and resume to sleep mode again.
The RP516 and RP517 are optimized to prolong battery life and are designed for applications that require a low supply voltage in between 0.3 and 1.2 V. This kind of power supply is tailored to support the newest generation of low power MCU’s, GPS/GNSS receiver/processors and other ICs which are required in IoT applications for a low power wireless sensor network and wearable devices.
The DC/DC Converters operate in a VFM mode and the efficiency at light loads in particular was considerably improved and has a peak at 75%, even at 0.01 mA output current an efficiency performance of about 67% is achieved (conditions: Vout=0.5V, Vin=1.8V).
The impressive low quiescent current of only 300 nA also contributes to extend battery life or makes it possible for the designer to select a smaller sized battery for the application. The main difference between the two products is their output current power; they deliver 100 and 300 mA respectively. Both products offer synchronous rectification and have high and low side MOSFET driver transistors embedded. Three different packages are available: A standard SOT-89-5, leadless DFN2527-10 or the most compact WLCSP-8-P1 package. By using the proposed external components, it takes up only 8.3 mm2 of printed circuit board area. Thanks to the wide input voltage range, the two DC/DC Converters are able to operate from various power supplies like a USB port, a single cell Li-Ion and other regular batteries.
Protection circuits are integrated: An Under Voltage Lock-Out circuit disabling the DC/DC Converter in case the input voltage drops below a minimum threshold. A soft-start circuit controls the output voltage to ramp-up smoothly, preventing any output overshoot and undershoot during the start-up period. The Lx current limit circuit prevents the peak current through the inductor to exceed a specific maximum current threshold.
The RP516 and RP517 have an optional auto-discharge function; this feature rapidly discharges the output capacitor once the CE pin disables the chip.
https://www.e-devices.ricoh.co.jp/en/products/power/dcdc/rp516/
https://www.e-devices.ricoh.co.jp/en/products/power/dcdc/rp517/
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