RP503x Series

600mA* Step-down DC/DC Converter with Synchronous Rectifier

Data Sheet / Flyer
Data Sheet * Flyer

The RP503x Series are low supply current CMOS-based 600mA* step-down DC/DC Converters with synchronous rectifier. Each of these ICs consists of an oscillator, a switching control circuit, a reference voltage unit, an error amplifier, a soft-start circuit, UVLO circuit, a latch protection circuit, switching transistors, and so on. A low ripple, high efficiency step-down DC/DC converter can be easily composed of this IC with only an inductor and capacitors.

In terms of the output voltage, since the feedback resistances are built-in, the voltage is fixed internally. 0.1V step output can be set by laser-trim and 1.5% or 18mV tolerance depending on the output voltage is guaranteed. RP503x is PWM/VFM auto switching control in which mode automatically switches from PWM mode to high-efficiency VFM mode in low output current. The efficiency in low output current (VFM mode) improved compared with existing products.

As protection circuits, the current limit circuit which limits peak current of Lx at each clock cycle, and the latch type protection circuit which works if the term of the over-current condition keeps on a certain time exist. The latch-type protection circuit works to latch an internal driver with keeping it disable. To release the condition of the protection, after disabling this IC with a chip enable circuit, enable it again, or restart this IC with power-on or make the supply voltage at UVLO detector threshold level or lower than UVLO.

Since packages are WLCSP-6-P2, DFN1616-6, SOT-23-5, high density mounting on boards is possible.

  • *) This is an approximate value, because output current depends on conditions and external parts.
Supply Current Typ. 20µA (at VFM mode, at no load)
Standby Current Max. 5µA
Input Voltage Range 2.5V to 5.5V (Absolute maximum rating; 6.5V)
Output Voltage Range 0.8V to 2.5V (0.1V step)
Output Voltage Accuracy ±1.5% (VOUT>=1.2V), ±18mV (VOUT<1.2V)
Temperature-Drift Coefficient of Output Voltage Typ. ±100ppm/°C
Oscillator Frequency Typ. 2.0MHz
Oscillator Maximum Duty Cycle Min. 100%
Built-in Driver ON Resistance Typ. Pch. 0.34Ω, Nch. 0.43Ω (VIN=3.6V)
UVLO Detector Threshold Typ. 2.2V
Soft Start Time Typ. 0.15ms
Lx Current Limit Typ. 800mA
Latch type Protection Circuit Typ. 1.5ms
Two choices of Switching Mode Automatic PWM/VFM mode change
Packages DFN1616-6, WLCSP-6-P2, SOT-23-5
  • Power source for battery-powered equipment.
  • Power source for hand-held communication equipment, cameras, VCRs, camcorders.
  • Power source for HDD, portable equipment.

Data Sheet Flyer Design Guide
RP503x Series RP503x Series RP503x Series
Package Info. Mark Info. Quality Assurance Data
DFN1616-6 RP503L Reliability
SOT-23-5 RP503N Reliability

All PDF files are less than 1MB unless otherwise stated.

Note : Discontinued Products
WLCSP-6-P2 (RP503Z Series) are already discontinued. Providing only for the customer under present adoption with stock.

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