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2A, 18V, 700kHz ACOT® Synchronous Step-Down Converter

RT7274/RT7279/RT7280/RT7281

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The RT7274/79/80/81 is a synchronous step-down DC/DC converter with Advanced Constant On-Time (ACOT®) mode control. It achieves high power density to deliver up to 2A output current from a 4.5V to 18V input supply. The proprietary ACOT® mode offers an optimal transient response over a wide range of loads and all kinds of ceramic capacitors, which allows the device to adopt very low ESR output capacitor for ensuring performance stabilization. In addition, RT7274/79/80/81 keeps an excellent constant switching frequency under line and load variation and the integrated synchronous power switches with the ACOT® mode operation provides high efficiency in whole output current load range. Cycle-by-cycle current limit provides an accurate protection by a valley detection of low-side MOSFET and external soft-start setting eliminates input current surge during startup. Protection functions include thermal shutdown for RT7274/79/80/81; output under voltage protection and output over voltage protection for RT7279/80 only.

Applications

  • Industrial and Commercial Low Power Systems
  • Computer Peripherals
  • LCD Monitors and TVs
  • Green Electronics/Appliances
  • Point of Load Regulation for High-Performance DSPs, FPGAs, and ASICs
  • LCD TV
Key Spec.
RT7274 RT7279 RT7280 RT7281
Status Active Active Active Active
Vin (min) (V) 4.5 4.5 4.5 4.5
Vin (max) (V) 18 18 18 18
Number of Outputs 1 1 1 1
Vout (min) (V) 0.765 0.765 0.765 0.765
Vout (max) (V) 8 8 8 8
Output Adj. Method Resistor Resistor Resistor Resistor
Iout (max) (A) 2 2 2 2
Current Limit (typ) (A) 3.5 3.5 3.5 3.5
Freq (typ) (kHz) 700 700 700 700
Ext Sync No No No No
Ron_HS (typ) (mOhm) 150 150 150 150
Ron_LS (typ) (mOhm) 105 105 105 105
Iq (typ) (mA) 0.7 0.7 0.7 0.7
Features ACOT Control;Adjustable Soft-Start;Enable Input;Fast Transient Response;OCP;PSM;Power Good;Stable with Ceramic Capacitor;UVP ACOT Control;Adjustable Soft-Start;Enable Input;Fast Transient Response;Force PWM;OCP;Power Good;Stable with Ceramic Capacitor;UVP ACOT Control;Adjustable Soft-Start;Enable Input;Fast Transient Response;OCP;PSM;Power Good;Stable with Ceramic Capacitor;UVP ACOT Control;Adjustable Soft-Start;Enable Input;Fast Transient Response;Force PWM;OCP;Power Good;Stable with Ceramic Capacitor;UVP
Package Type PSOP-8 TSSOP-14(PP);WDFN3x3-10 TSSOP-14(PP);WDFN3x3-10 PSOP-8
Features
  • ACOTTM Mode Enables Fast Transient Response
  • 4.5V to 18V Input Voltage Range
  • 2A Output Current
  • High Efficient Internal N-MOSFET Optimized for Lower Duty Cycle Applications
  • 105mΩ Internal Low-Side N-MOSFET
  • Advanced Constant On-Time Control
  • Allows Ceramic Output Capacitor
  • 700kHz Switching Frequency
  • Adjustable Output Voltage from 0.765V to 8V
  • Adjustable and Pre-biased Soft-Start
  • Cycle-by-Cycle Current Limit
  • Input Under Voltage Lockout
  • Thermal Shutdown
  • RoHS Compliant and Halogen Free
Datasheet
TitleLast UpdateShareDownload
2A, 18V, 700kHz ACOT® Synchronous Step-Down Converter2013/02/25
Technical Documents
TitleLast UpdateShareDownload
ACOT™ Stability Testing2019/12/12
The Calculation of Output DC Offset for ACOT™ Control Buck Converter with Feed-forward Compensator2019/12/12
ACOT™ (Advanced Constant-On Time) Synchronous Step-Down Converters2019/12/12
Comparing Buck Converter Topologies2019/12/12
Buck Converter Selection Criteria2019/12/12
Videos
TitleLast UpdateShareViews
How to estimate control loop bandwidth from the transient response time?2017/03/30 688
Introduction to Richtek's Advanced Constant On Time Buck Converters2013/05/14 55
Evaluation Boards
TitleLast UpdateShareDownload
RT7280GQW Evaluation Board2018/11/08
RT7279GQW Evaluation Board2018/11/08
Reference Design
TitleLast UpdateShareDownload
Richtek Load Transient Tool2019/01/09
Design Tool
TitleLast UpdateShare
Richtek Designer™ Web Simulation Tool : RT7279GCP2020/02/05
Richtek Designer™ Web Simulation Tool : RT7279GQW2020/02/05
Richtek Designer™ Web Simulation Tool : RT7280GCP2020/02/05
Richtek Designer™ Web Simulation Tool : RT7280GQW2020/02/05
Richtek Designer™ Web Simulation Tool : RT7281GSP2020/02/05
Richtek Designer™ Web Simulation Tool : RT7274GSP2020/02/05
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT7274GSPPSOP-82500 Request Buy from Distributor
RT7279GCPTSSOP-14(PP)2500 Not available Buy from Distributor
RT7279GQWWDFN3x3-101500 Not available Buy from Distributor
RT7280GCPTSSOP-14(PP)2500 Not available Buy from Distributor
RT7280GQWWDFN3x3-101500 Not available Buy from Distributor
RT7281GSPPSOP-82500 Not available Buy from Distributor
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