5A, 18V, 650kHz, ACOT® Synchronous Step-Down Converter


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The RT7235/36/39/40 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 5A 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, RT7235/36/39/40 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 RT7235/36/39/40, output Under Voltage Protection (UVP) / Over Voltage Protection (OVP) for RT7235/36. When the UVP/OVP is triggered, the device will enter latch mode for TSSOP-14 (Exposed Pad), and hiccup mode for WDFN-10L 3x3.

The RT7235/36 are available in TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 packages, and the RT7235 is operated in forced continuous conduction mode.

The RT7239/40 are available in the SOP-8 (Exposed Pad) package, and the RT7239 is operated in forced continuous conduction mode.


  • 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
TitleLast UpdateShareDownload
5A, 18V, 650kHz, ACOT® Synchronous Step-Down Converter2013/02/25
Technical Documents
TitleLast UpdateShareDownload
Richtek Selection Guide [Oct., 2020]2020/12/28
ACOT™ (Advanced Constant-On Time) Synchronous Step-Down Converters2020/12/28
ACOT® Stability Testing2020/04/13
The Calculation of Output DC Offset for ACOT™ Control Buck Converter with Feed-forward Compensator2019/12/12
Comparing Buck Converter Topologies2019/12/12
Buck Converter Selection Criteria2019/12/12
DC/DC Converter Testing with Fast Load Transient2019/06/04
TitleLast UpdateShareViews
How to estimate control loop bandwidth from the transient response time?2017/03/30 1202
Introduction to Richtek's Advanced Constant On Time Buck Converters2013/05/14 74
Part NumberPackage TypePackage Qty.Free SampleBuy From Authorized Distributor
RT7235GCPTSSOP-14(PP)2500 Request Buy from Distributor
RT7235GQWWDFN3x3-101500 Request Buy from Distributor
RT7236GCPTSSOP-14(PP)2500 Not available Buy from Distributor
RT7236GQWWDFN3x3-101500 Request Buy from Distributor
RT7240GSPPSOP-82500 Not available Buy from Distributor