4.5A Step-Up DC/DC Converter


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The RT8509A is a high performance switching Boost converter that provides a regulated supply voltage for active matrix thin film transistor (TFT) liquid crystal displays (LCDs).

The RT8509A incorporates current mode, fixed-frequency, pulse width modulation (PWM) circuitry with a built in N-MOSFET to achieve high efficiency and fast transient response.

The RT8509A has a wide input voltage range from 2.8V to 14V. In addition, the output voltage can be adjusted up to 24V via an external resistive voltage divider. The maximum peak current is limited to 4.5A (min.). Other features include adjustable soft-start, over-voltage protection, and over-temperature protection.

The RT8509A is available in the WDFN-12L 5x5 package.


  • GIP TFT-LCD Panels
Key Spec.
Status Active
Vin (min) (V) 2.8
Vin (max) (V) 14
Vout (min) (V) 3.5
Vout (max) (V) 24
Output Adj. Method Resistor
Iq (typ) (mA) 5
SW Current Limit (typ) (A) 5
Freq (typ) (kHz) 1200
Freq (min) (kHz) 1000
Freq (max) (kHz) 1500
Ron (typ) (Ohm) 0.1
Features Current Mode Control;Enable Input;OCP;OVP;Stable with Ceramic Capacitor
Package Type WDFN5x5-12
  • 90% Efficiency
  • Adjustable Output Up to 24V
  • 2.8V to 14V Input Supply Voltage
  • Input Supply Under-Voltage Lockout
  • Fixed 1.2MHz Switching Frequency
  • Adjustable Soft-Start
  • VOUT Over-Voltage Protection
  • Over-Temperature Protection
  • Thin 12-Lead WDFN Package
  • RoHS Compliant and Halogen Free
TitleLast UpdateShareDownload
4.5A Step-Up DC/DC Converter2013/11/19
Technical Documents
TitleLast UpdateShareDownload
Power IC Solutions for IoT/Portable/Wearable/Battery-Powered Applications2020/12/30
Richtek Selection Guide [Oct., 2020]2020/12/30
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT8509AGQWWDFN5x5-121500 Not available Buy from Distributor