RICOH RP502x SERIES Data Sheet User Manual

RP502x SERIES

Step-down DC/DC Converter with Synchronous Rectifier

NO.EA-189-111124

OUTLINE The RP502x Series are CMOS-based step-down DC/DC converters with synchronous rectifier. Each of these ICs consists of an oscillator, a reference voltage unit, an error amplifier, a switching control circuit, a soft-start circuit, protection circuits, an UVLO circuit, and switching transistors. By adopting the synchronous rectification with built-in switching transistors, high efficient step-down DC/DC converter can be composed of only an inductor and capacitors. As protection circuits, the current limit circuit and the latch protection circuit are built into the ICs. The current limit circuit controls the peak current of LX at each clock cycle. Latch protection circuit maintains the built-in driver in OFF state if the load current exceeds the limit value for a certain period of time. To cancel the latch protection, disable the ICs with a chip enable circuit and then enable it again or make the power supply voltage lower than UVLO. The setting voltage for the RP502x Series is the output voltage fixed type with built-in feedback resistance that is adjustable in 0.1V step with the accuracy of ± 1.5% or ±24m V. The packages for the ICs are WLCSP-6-P2 and DFN1616-6, which enable the high-density mounting. The switching mode for the ICs is selectable from the PWM/VFM auto switching type, which achieves the high efficiency at the light load condition or PWM fixed type, which switches at the fixed frequency.

FEATURES • Supply Current ......................................................Typ. 750μA (at normal) Typ. 180μA (at light road) • Input Voltage Range .............................................2.5V to 5.5V(VOUT≥1.0V) 2.5V to 4.5V(VOUT<1.0V) • Absolute Maximum Ratings ..................................6.0V • Output Voltage Range...........................................0.8V to 3.3V (0.1V steps) • Output Voltage Accuracy.......................................±1.5% (VOUT≥1.6V) ±24m V (VOUT<1.6V) • Oscillator Frequency .............................................Typ. 3.3MHz • Maximum Duty ......................................................Min. 100% • Built-in Driver ON Resistance ...............................Typ. Pch. 0.5Ω, Nch. 0.5Ω(VIN=3.6V) • UVLO Detector Threshold.....................................Typ. 2.2V • Soft Start Time.......................................................Typ. 0.12ms • Lx Current Limit.....................................................Typ. 900m A(VOUT≥1.2V) Typ. 800m A(VOUT<1.2V) • Latch type Protection Circuit .................................Typ. 1.5ms • Chip Enable Function............................................"H" Active • Packages ..............................................................WLCSP-6-P2, DFN1616-6

APPLICATIONS • Power source for battery-powered equipments. • Power source for hand-held communication equipments, cameras, VCRs, camcorders. • Power source for HDDs, portable equipments.