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The RT6251A/B is a high efficiency, monolithic synchronous step-down DC/DC converter that can deliver up to 3A output current from a 4.5V to 18V input supply. The RT6251A/B current-mode architecture with external compensation allows the transient response to be optimized over a wide range of loads and output capacitors. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates input current surge during start-up. Fault condition protections include output under-voltage protection, output over-voltage protection, and over-temperature protection. The low current shutdown mode provides output disconnection, enabling easy power management in battery-powered systems.

Applications

  • High Performance Point of Load Regulation
  • Notebook Computers
  • High Density and Distributed Power Systems
Key Spec.
RT6251A RT6251B
Status EOL EOL
Vin (min) (V) 4.5 4.5
Vin (max) (V) 18 18
Number of Outputs 1 1
Vout (min) (V) 0.8 0.8
Vout (max) (V) 15 15
Output Adj. Method Resistor Resistor
Iout (max) (A) 3 3
Current Limit (typ) (A) 6.2 6.2
Freq (typ) (kHz) 480 480
Freq (min) (kHz) 200 200
Freq (max) (kHz) 1200 1200
Ext Sync Yes Yes
Ron_HS (typ) (mOhm) 46 46
Ron_LS (typ) (mOhm) 36 36
Iq (typ) (mA) 0.8 0.6
Features 100% Duty Cycle;Adjustable Frequency;Adjustable Soft-Start;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;External Synchronization;OCP;OTP;PSM;Power Good;Stable with Ceramic Capacitor;UVP 100% Duty Cycle;Adjustable Frequency;Adjustable Soft-Start;Current Mode Control;Cycle-by-Cycle Current Limit;Enable Input;External Synchronization;Force PWM;OCP;OTP;Power Good;Stable with Ceramic Capacitor;UVP
Package Type WQFN3.5x3.5-14A WQFN3.5x3.5-14A
Features
  • Low RDS(ON) Power MOSFET Switches 46mΩ/36mΩ
  • Input Voltage Range : 4.5V to 18V
  • Adjustable Switching Frequency : 200kHz to 1.2MHz
  • Current-Mode Control
  • Synchronous to External Clock : 200kHz to 1.2MHz
  • Accurate Voltage Reference 0.8V ± 1%
  • Monotonic Start-Up into Pre-biased Outputs
  • Adjustable Soft-Start
  • Power Good Indicator
  • Under-Voltage and Over-Voltage Protection
  • Input Under-Voltage Lockout
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