Reference Design Sample & Design Tools Buy RT7235/36/39/40 TM 5A, 18V, 650kHz, ACOT Synchronous Step-Down Converter Features General Description TM zz z zz ACOT Mode Enables Fast Transient Response The RT7235/36/39/40 is a synchronous step-down DC/ TM zz z zz 4.5V to 18V Input Voltage Range DC converter with Advanced Constant On-Time (ACOT ) zz z zz 5A Output Current mode control. It achieves high power density to deliver up zz z zz 35m Internal Low Site N-MOSFET to 5A output current from a 4.5V to 18V input supply. The TM zz z zz Advanced Constant On-Time Control proprietary ACOT mode offers an optimal transient zz z zz Support All Ceramic Capacitors response over a wide range of loads and all kinds of ceramic zz z zz Up to 95% Efficiency capacitors, which allows the device to adopt very low ESR zz z zz 650kHz Switching Frequency at all Load Current output capacitor for ensuring performance stabilization. In (RT7235, RT7239) addition, RT7235/36/39/40 keeps an excellent constant zz z zz Discontinuous Operating Mode at Light Load switching frequency under line and load variation and the TM (RT7236, RT7240) integrated synchronous power switches with the ACOT zz z zz Adjustable Output Voltage from 0.765V to 8V mode operation provides high efficiency in whole output zz z zz Adjustable Soft-Start current load range. Cycle-by-cycle current limit provides zz z zz Cycle-by-Cycle Current Limit an accurate protection by a valley detection of low side zz z zz Input Under Voltage Lockout MOSFET and external soft-start setting eliminates input zz z zz Thermal Shutdown current surge during startup. Protection functions include zz z zz RoHS Compliant and Halogen Free thermal shutdown for RT7235/36/39/40, output Under Voltage Protection (UVP) / Over Voltage Protection (OVP) Applications for RT7235/36. When the UVP/OVP is triggered, the device z Industrial and Commercial Low Power Systems will enter latch mode for TSSOP-14 (Exposed Pad), and z Computer Peripherals hiccup mode for WDFN-10L 3x3. z LCD Monitors and TVs The RT7235/36 are available in TSSOP-14 (Exposed Pad) z Green Electronics/Appliances and WDFN-10L 3x3 packages, and the RT7235 is operated z Point of Load Regulation for High-Performance DSPs, in forced continuous conduction mode. FPGAs, and ASICs The RT7239/40 are available in the SOP-8 (Exposed Pad) package, and the RT7239 is operated in forced continuous conduction mode. Simplified Application Circuit RT7235/36/39/40 V VIN V IN SW OUT VCC* BOOT Enable EN FB Power GOOD PGOOD* PGND VREG5 VS* * : VCC pin for TSSOP-14 (Exposed Pad) only. SS GND* VS pin for TSSOP-14 (Exposed Pad) only. GND pin for TSSOP-14 (Exposed Pad) only. PGOOD pin for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only. Copyright 2018 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS7235/36/39/40-09 February 2018 www.richtek.com 1RT7235/36/39/40 Ordering Information Marking Information Continuous Switching Mode RT7235GCP RT7235GCP : Product Number RT7235 RT7235GCP YMDNN : Date Code Package Type YMDNN CP : TSSOP-14 (Exposed Pad) QW : WDFN-10L 3x3 (W-Type) Lead Plating System RT7235GQW G : Green (Halogen Free and Pb Free) 1N= : Product Code YMDNN : Date Code 1N=YM RT7239 DNN Package Type SP : SOP-8 (Exposed Pad-Option 2) Lead Plating System RT7239GSP G : Green (Halogen Free and Pb Free) RT7239GSP : Product Number RT7239 YMDNN : Date Code GSPYMDNN Discontinuous Operating Mode RT7236GCP RT7236 RT7236GCP : Product Number Package Type RT7236GCP CP : TSSOP-14 (Exposed Pad) YMDNN : Date Code YMDNN QW : WDFN-10L 3x3 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) RT7236GQW 1M= : Product Code RT7240 YMDNN : Date Code 1M=YM Package Type DNN SP : SOP-8 (Exposed Pad-Option 2) Lead Plating System G : Green (Halogen Free and Pb Free) RT7240GSP Note : RT7240GSP : Product Number RT7240 Richtek products are : YMDNN : Date Code GSPYMDNN RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. Pin Configurations (TOP VIEW) VS 14 VCC 2 13 FB VIN 3 12 BOOT VREG5 8 EN VIN 4 11 EN 1 10 VIN SS PGND SW 2 7 FB BOOT 9 2 VIN FB 5 10 GND SW PGND 8 3 VREG5 BOOT 3 6 VREG5 SW 6 9 PGOOD PGND 15 9 SS 4 7 SW 11 7 8 4 5 PGND 5 SS EN PGOOD SW PGND TSSOP-14 (Exposed Pad) WDFN-10L 3x3 SOP-8 (Exposed Pad) Copyright 2018 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS7235/36/39/40-09 February 2018 2 PGND 9