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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 (ACOTTM) mode control. It achieves high power density to deliver up to 2A output current from a 4.5V to 18V input supply. The proprietary ACOTTM 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 ACOTTM 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 Testing2019/03/18
ACOT™ (Advanced Constant-On Time) Synchronous Step-Down Converters2018/11/15
Comparing Buck Converter Topologies2018/09/20
Buck Converter Selection Criteria2016/08/04
The Calculation of Output DC Offset for ACOT™ Control Buck Converter with Feed-forward Compensator2016/07/07
Videos
TitleLast UpdateShareViews
How to estimate control loop bandwidth from the transient response time?2017/03/30 583
Introduction to Richtek's Advanced Constant On Time Buck Converters2013/05/14 50
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 : RT7279GCP2019/09/11
Richtek Designer™ Web Simulation Tool : RT7279GQW2019/09/11
Richtek Designer™ Web Simulation Tool : RT7280GCP2019/09/11
Richtek Designer™ Web Simulation Tool : RT7280GQW2019/09/11
Richtek Designer™ Web Simulation Tool : RT7281GSP2019/09/11
Richtek Designer™ Web Simulation Tool : RT7274GSP2019/09/11
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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