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RP509 Series

0.5A/1A 6MHz PWM/VFM Step-down DC/DC Converter with Synchronous Rectifier

  • Consumer
  • PLP
  • RoHS

The RP509 is a low supply current PWM/VFM step-down DCDC converter with synchronous rectifier featuring 0.5A / 1A output current.

Output voltage controlling method is selectable between a forced PWM control type and a PWM/VFM auto-switching control type, and can be set by the MODE pin.

Internally, a single converter consists of a reference voltage unit, an error amplifier, a switching control circuit, a mode control circuit, a soft-start circuit, an under-voltage lockout (UVLO) circuit, a thermal shutdown circuit, and switching transistors.

Furthermore, RP509 is current limit circuit and thermal shutdown circuit. Lx current limit value (Typ.) is selectable between 1.6 A and 1.0 A.

The RP509Z is available in WLCSP−6−P6 which achieves high-density mounting on boards. A high frequency of 6 MHz enables to use capacitor of 0402- / 1005-size (inch / mm) and inductor of 0603- /1608-size (inch / mm) as external parts help to save space for devices.The RP509N is available in SOT-23-6.

Specs & Datasheets

Input Voltage Range 2.3 V to 5.5 V (6.5 V)
Operating Temperature Range -40°C to 85°C (125°C)
Supply Current Typ. 15 µA
Standby Current Typ. 0 µA
Output Voltage Range Internally Fixed Ver.: 0.6 V to 3.3 V (0.1 V step)
Externally Adjustable Ver.: 0.6 V to 5.5 V
Output Voltage Accuracy ±1.5% (VSET ≥ 1.2 V, Ta = 25°C), ±18 mV (VSET < 1.2 V)
Output Voltage Temperature Coefficient ±100 ppm/°C
Feedback Voltage 0.6 V
Feedback Voltage Accuracy ±9 mV
Feedback Voltage Temperature Coefficient ±100 ppm/°C
Output Current 0.5 A, 1 A
Driver ON-resistance Pch: Typ. 0.175 Ω, Nch; Typ. 0.155 Ω (RP509Z)
Pch: Typ. 0.195 Ω, Nch: Typ. 0.175 Ω (RP509N)
Oscillator Frequency Typ. 6 MHz
Maximum Duty Cycle Min. 100%
Package WLCSP-6-P6, SOT-23-6

Download Datasheet

Protections / Functions

Functional Description

TSD ILX OCP OVP UVLO OVLO Reverse Shutdown Soft Start SSCG PGOOD Auto Discharge Anti-ringing Sequencing Max Duty Ext. Phase LED Adjust

Technical Documents

Typical Application (Fixed Output Voltage Type)

Typical Application (Fixed Output Voltage Type)

CIN: 4.7 µF
COUT: 10 µF
L: 0.47 µH

Typical Application (Adjustable Output Voltage Type)

Typical Application (Adjustable Output Voltage Type)

CIN: 4.7 µF
COUT: 10 µF
L: 0.47 µH

Efficiency vs. Output Current VOUT=1.8V, VMODE = "L" PWM/VFM Auto Switching

Efficiency vs. Output Current VOUT=1.8V, VMODE =


Efficiency vs. Output Current VOUT=3.3V Fixed, VMODE = "L" PWM/VFM Auto Switching

Efficiency vs. Output Current VOUT=3.3V Fixed, VMODE =


Quality & Packages

Product Name Compatibility Package Marking Reliability
  • gradeConsumerC
  • plpP
WLCSP-6-P6 RP509Z RP509Z-F
  • gradeConsumerC
  • plpP
SOT-23-6 RP509N RP509N-FE

Refer to the datasheets for the details on the product.
The package file includes package dimensions, taping specifications, taping reels dimensions, power dissipations, and recommended land pattern.
Please contact us or our distributors for unpublished reliability information.

Sample / Buy

Functional Description

TSD Thermal Shutdown Function
ILX LX Current Limit Function
OCP Overcurrent Protection
OVP Overvoltage Protection
UVLO Undervoltage Lockout Protection
OVLO Overvoltage Lockout Protection
Reverse Reverse Current Protection Circuit
Shutdown Shutdown Function
Soft Start Soft Start Function
SSCG Spread Spectrum Clock Generator Function
PGOOD Power Good Output
Auto Discharge Auto Discharge Function
Anti-ringing Anti-ringing Switch Function
Sequencing Start-up Sequencing Control
Max Duty Maximum Duty Cycle
Ext. Phase Externally Adjustable Phase Compensation
LED Adjust LED High-speed Dimming Control

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