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The RT8251 is a monolithic step-down switch mode converter with a built-in internal power MOSFET. It achieves 5A continuous output current over a wide input supply range with excellent load and line regulation. Current mode operation provides fast transient response and eases loop stabilization.
The RT8251 provides protection functions such as cycle-by-cycle current limiting and thermal shutdown. In shutdown mode, the regulator draws 25μA of supply current. Programmable soft-start minimizes the inrush supply current and the output overshoot at initial startup. The RT8251 requires a minimum number of external components. The RT8251 is available in WQFN-16L 3x3 and SOP-8 (Exposed Pad) packages.

Applications

  • Distributed Power Systems
  • Battery Charger
  • DSL Modems
  • Pre-regulator for Linear Regulators
Key Spec.
RT8251
Status Active
Vin (min) (V) 4.75
Vin (max) (V) 24
Number of Outputs 1
Vout (min) (V) 0.8
Vout (max) (V) 15
Output Adj. Method Resistor
Iout (max) (A) 5
Current Limit (typ) (A) 6.8
Freq (typ) (kHz) 570
Ext Sync No
Ron_HS (typ) (mOhm) 70
Ron_LS (typ) (mOhm) 15
Iq (typ) (mA) 0.8
Features Adjustable Soft-Start;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;Force PWM;OCP;OTP;Stable with Ceramic Capacitor;UVP
Package Type PSOP-8;WQFN3x3-16
Features
  • Wide Operating Input Voltage Range : 4.75V to 24V
  • Adjustable Output Voltage Range : 0.8V to 15V
  • Output Current up to 5A
  • 25μA Low Shutdown Current
  • Internal Power MOSFET : 70mΩ
  • High Efficiency up to 95%
  • 570kHz Fixed Switching Frequency
  • Stable with Low ESR Output Ceramic Capacitors
  • Thermal Shutdown Protection
  • Cycle-By-Cycle Over Current Protection
  • RoHS Compliant and Halogen Free
Datasheet
TitleLast UpdateDownload
5A, 24V, 570kHz Step-Down Converter2011/10/05
Technical Documents
TitleItem TypeLast UpdateDownload
Richtek Product Selection Guide [Jan., 2024] Selection Guide2024/01/18
Richtek Featured Product Tree [Aug., 2023] Selection Guide2023/08/07
Reference Design
TitleLast UpdateDownload
Richtek Load Transient Tool2022/07/25
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT8251GQWWQFN3x3-161500 Request Buy from Distributor
RT8251GSPPSOP-82500 Request Buy from Distributor
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