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The RT6257A/B is a high-performance, synchronous step-down DC-DC converter that can deliver up to 6A output current from a 4.5V to 18V input supply. The device integrates low RDS(ON) power MOSFETs, accurate 0.6V reference and an integrated diode of bootstrap circuit to offer a very compact solution.

The RT6257A/B adopts Advanced Constant On-Time (ACOT®) control architecture that provides ultrafast transient response and further reduces the external-component count. In steady states, the ACOT® operates in nearly constant switching frequency over line, load and output voltage ranges and makes the EMI filter design easier.

The device offers Independent enable control input pin for easily sequence control. To control the inrush current during the startup, the device provides a fixed 1.5ms soft-start up. Fully protection features are also integrated in the device including the cycle-by-cycle current limit control, UVP, input UVLO and OTP.

The RT6257A/B is available in the TSOT-23-6 (FC) package.

Applications

  • Set Top Box
  • Portable TV
  • Access Point Router
  • DSL Modem
  • LCD TV
Key Spec.
RT6257A RT6257B
Status Active Active
Vin (min) (V) 4.5 4.5
Vin (max) (V) 18 18
Number of Outputs 1 1
Vout (min) (V) 0.6 0.6
Vout (max) (V) 5 5
Output Adj. Method Resistor Resistor
Iout (max) (A) 6 6
Current Limit (typ) (A) 8.5 8.5
Freq (typ) (kHz) 500 500
Ext Sync No No
Ron_HS (typ) (mOhm) 30 30
Ron_LS (typ) (mOhm) 20 20
Iq (typ) (mA) 0.115 0.115
Features ACOT Control;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;OTP;PSM;Power Good;SCP;Stable with Ceramic Capacitor;UVP ACOT Control;Cycle-by-Cycle Current Limit;Enable Input;Fast Transient Response;OTP;PSM;Power Good;SCP;Stable with Ceramic Capacitor;UVP
Package Type TSOT-26(FC) TSOT-26(FC)
Features
  • 4.5V to 18V Input Voltage Range
  • 6A Output Current
  • Constant-On-Time Mode to Enables Fast Transient Response
  • Low Output Ripple and Allows Ceramic Output Capacitor
  • 500kHz Switching Frequency
  • High Efficient Internal Power MOSFET Switch Optimized for Lower Duty Cycle Applications
  • Integrated 30mΩ/20mΩ MOSFETs
  • Adjustable Output Voltage from 0.6V to 5V
  • Internal Soft-Start (1.5ms typ.)
  • Built-In UVP/OTP
  • Input Under Voltage Lockout
  • TSOT23-6 (FC) Package
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 SampleDistributorStockBuy From Authorized Distributor
RT6257BHGJ6FTSOT-26(FC)3,000 Request Digikey 2,700 Buy
Mouser 2,955 Buy
Evaluation Board
Part NumberDistributorStockBuy From Authorized Distributor
EVB_RT6257AHGJ6F Digikey 1 Buy
Mouser 0 Lead-Time: 14 weeks
Please confirm with our distributor or sales representative for actual stock status.
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