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3A, 18V, 700kHz ACOT™ Synchronous Step-Down Converter

RT7277

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The RT7277 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 3A 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 capacitors for ensuring performance stabilization. In addition, RT7277 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 also include output under voltage protection, output over voltage protection, and thermal shutdown.

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
Key Spec.
RT7277
Status Active
Vin (min) (V) 4.5
Vin (max) (V) 18
Number of Outputs 1
Vout (min) (V) 0.765
Vout (max) (V) 8
Output Adj. Method Resistor
Iout (max) (A) 3
Current Limit (typ) (A) 4.1
Freq (typ) (kHz) 700
Ext Sync No
Ron_HS (typ) (mOhm) 90
Ron_LS (typ) (mOhm) 60
Iq (typ) (mA) 0.7
Features ACOT Control;Adjustable Soft-Start;Enable Input;Fast Transient Response;Force PWM;OCP;Stable with Ceramic Capacitor
Package Type PSOP-8
Features
  • ACOTTM Mode Enables Fast Transient Response
  • 4.5V to 18V Input Voltage Range
  • 3A Output Current
  • 60mΩ Internal Low Site N-MOSFET
  • Advanced Constant On-Time Control
  • Support All Ceramic Capacitors
  • Up to 95% Efficiency
  • 700kHz Switching Frequency
  • Adjustable Output Voltage from 0.765V to 8V
  • Adjustable Soft-Start
  • Cycle-by-Cycle Current Limit
  • Input Under Voltage Lockout
  • Thermal Shutdown
  • RoHS Compliant and Halogen Free
Datasheet
TitleLast UpdateShareDownload
3A, 18V, 700kHz ACOT™ Synchronous Step-Down Converter2012/08/06
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
Reference Design
TitleLast UpdateShareDownload
Richtek Load Transient Tool2019/01/09
Design Tool
TitleLast UpdateShare
Richtek Designer™ Web Simulation Tool : RT7277GSP2019/09/11
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT7277GSPPSOP-82500 Not available Buy from Distributor
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