RP502x SERIES
Step-down DC/DC Converter with Synchronous Rectifier
NO.EA-189-100617
1
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 ±24mV. The packages for the ICs are WLCSP-6-P2
(Under development) 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. 180
μA (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)
±24mV (VOUT<1.6V)
Oscillator Frequency .............................................Typ. 3.3MHz
Maximum Duty ......................................................Min. 100%
Built-in Driver ON Resistance ...............................Typ. Pch. 0.5, Nch. 0.5(VIN=3.6V)
UVLO Detector Threshold.....................................Typ. 2.2V
Soft Start Time.......................................................Typ. 0.12ms
Lx Current Limit.....................................................Typ. 900mA(VOUT≥1.2V)
Typ. 800mA(VOUT<1.2V)
Latch type Protection Circuit.................................Typ. 1.5ms
Chip Enable Function............................................"H" Active
Packages ..............................................................WLCSP-6-P2 (Under development), 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.