EVB_RT7238BGQUF

RT7238B/C/D GQUF Evaluation Board your power partner. Synchronous Step-Down Converter’s Evaluation Board for RT7238 Integrated Chip Purpose The RT7238B/C/D is an advance integrative chip, which includes a LDO regulator and a synchronous Buck converter. This document explains the function and use of the RT7238 evaluation board (EVB) and provides information to enable operation and modification of the evaluation board and circuit to suit individual requirements. Table of Contents Purpose ................................................................................................................................................................. 1 Introduction............................................................................................................................................................ 2 Application ............................................................................................................................................................. 2 Key Performance Summary Table .......................................................................................................................... 2 Bench Test Setup Conditions ................................................................................................................................. 3 Schematic, Bill of Materials & Board Layout ........................................................................................................... 5 More Information.................................................................................................................................................... 9 Important Notice for Richtek Evaluation Board ....................................................................................................... 9 RT7238B/C/D GQUF-00 October 2015 1 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. Introduction General Product Description The RT7238B/C/D is an advanced constant on-time (ACOT™) mode synchronous step-down converter. The main control loop of RT7238B/C/D using an advanced constant on-time (ACOT™) mode control which provides a very fast transient response. The RT7238B/C/D operates from 8V to 23V input voltage. For the RT7238D, the output voltage can be adjusted between 0.6V to 5V. The RT7238B/C/D is available in the UQFN-10L 3x3 (FC) package. Product Features             Advanced Constant On-Time (ACOT) Control 8V to 23V (RT7238B/C/D) Input Voltage Range @ 8A Output Current ACOT™ Mode Performs Fast Transient Response ACOT™ Architecture to Enable all MLCC Output Capacitor Usage Fixed 500kHz Switching Frequency High Efficient Internal Power MOSFET Switch  27mΩ (High-Side) and 10mΩ (Low-Side) Adjustable Output Voltage from 0.9V to 5V (RT7238D) Fixed 3.3V (RT7238B/D) or 5V (RT7238C) LDO Output Supplies 70mA Pre-biased Soft-Start Cycle-by-Cycle Over-Current Protection Input Under-Voltage Lockout Thermal Shutdown Output Over/Under-Voltage Protection Application  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 Performance Summary Table Key Features Evaluation Board Number : PCB029_V1 Default Input Voltage 8V to 23V Max Output Current 8A Default Output Voltage 3.3V (RT7238B) 5.1V (RT7238C) 1.05V (RT7238D) Default Marking & Package Type RT7238B/C/D, UQFN-10L 3x3 (FC) Operation Frequency 500kHz RT7238B/C/D GQUF-00 October 2015 2 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. Bench Test Setup Conditions Headers Description and Placement RT7238B Top View RT7238B Bottom View RT7238C Top View RT7238C Bottom View RT7238D Top View RT7238D Bottom View Please carefully inspect the EVB IC and external components, comparing them to the following Bill of Materials, to ensure that all components are installed and undamaged. If any components are missing or damaged during transportation, please contact the distributor or send e-mail to evb_service@richtek.com RT7238B/C/D GQUF-00 October 2015 3 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. Test Points, Jumpers and Switches The EVB is provided with the test points, jumpers, switches and individual names listed in the table below. Signal Test point/ name Description (expected waveforms or voltage levels on test points) VIN Input voltage Input voltage range 8V to 23V VOUT Output voltage Output voltage 3.35V(RT7238B), 5.1V(RT7238C), adjustable(RT7238D) LX LX voltage Switch Node BS BOOT voltage Bootstrap supply for high-side gate driver. EN2/LDO/BYP EN2/LDO/BYP voltage Enable Control Input of the IC and Internal LDO for RT7238B Internal 5V LDO Output for RT7238C Bypass Input for the Internal LDO for RT7238D LDO/VCC/LDO LDO/VCC/LDO voltage Internal 3.3V LDO Output for RT7238B/D No Internal Connection for RT7238C FB/FB/ILMIT LDO/VCC/LDO voltage Current Limit Setting for RT7238D No Internal Connection for RT7238B/C PG PG voltage Power Good Indicator.This pin connect to LDO output through R3. EN1/EN/EN EN1/EN/EN voltage Enable Control Input of the DC/DC Regulator. GND Ground Ground Jumpers/ name Signal Description (expected waveforms or voltage levels on test points) JP1 Output voltage Output voltage 3.35V(RT7238B), 5.1V(RT7238C), adjustable(RT7238D) JP2 Current Limit Setting voltage This jumper only provides current limit setting function for RT7238D Please remove R16, short R10 R14 C18 and short this jumper when setting the current limit. VOUT/BYP/EN2 voltage This jumper provides different setteings for RT7238B/D. When this EVB applis for RT7238D, this jumper can provide BYP pin bypass to buck output voltage function as BYP shorting to VOUT.When this EVB applis for RT7238B, please short the BYP to EN2. JP3 Switches/ name SW1 RT7238B/C/D GQUF-00 Signal EN1 voltage EN2 voltage ILMT_L voltage ILMT_H voltage October 2015 Description (expected waveforms or voltage levels on test points) This switch provide EN1, EN2, and current limit setting functions. When this EVB applis for RT7238C/D/E, the EN1 switch is used to enable EN. When this EVB applis for RT7238D, it can set ILMIT pin to “floating” by turn off ILMT_L and ILMT_H, “0” by turn on ILMT_L and turn off ILMT_H and “1” by turn off ILMT_L and turn on ILMT_H. In order to avoid function fail. Please don’t turn on ILMT_L and ILMT_H simultaneiously. 4 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. Power-up & Operating Guideline 1. RT7238B starts work by providing VIN voltage then turn on EN1 and EN2 switches. In the RT7238B application, the BYP and VOUT of jumper JP3 must always short together and resistor R4 must always be shorted. 2. RT7238C starts work by providing VIN voltage then turn on EN1 switches. In the RT7238C application, the resistor R4 must always be shorted. 3. RT7238D starts work by providing VIN voltage then turn on EN1 switches. In the RT7238D application, the output voltage can be setted by individual resistor R4 and R5. Moreover, the current limt threshold can be chosen through ILMIT_L and ILMIT_H switches after the jumper J2 , resistor R14, R10 and capacitor C18 are shorted. Schematic, Bill of Materials & Board Layout EVB Schematic Diagram RT7238B/C/D GQUF-00 October 2015 5 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. Bill of Materials Reference Q'ty Part Number Description Package Manufacture C3, C4 2 C1608X5R0J475KT000N 4.7µF/6.3V/0603/X5R 0603 TDK L1 1 7443340100 1µH for RT7238D 2.2µH for RT7238B/C 8 x 8 x 7.5 mm GOTREND C6, C9 2 C1608X7R1H104KT000N 0.1µF/50V/0603/X5R 0603 TDK C8, C10 2 GRM31CR61A226KE19L 22µF/25V/1206/X5R 1206 muRata C11, C12, C13, C14 4 C3225X5R1E226MT 22µF/25V/1210/X5R 1210 TDK BYP/EN2/VCC 1 Gold PIN Gold PIN Gold PIN Gold PIN LDO/VCC/LDO 1 Gold PIN Gold PIN Gold PIN Gold PIN J1, J2, J3, J4 4 Connector Connector Connector Connector GND 2 Gold PIN Gold PIN Gold PIN Gold PIN JP1 ,JP2, J6 3 Jumper Jumper Jumper Jumper R1, R2, R8, R10, R12, R15, R16 7 Shorted Shorted Shorted Shorted R3, R7 2 0603 100K 1% 100kΩ/0603/1% 0603 WALSIN R6, R13 2 0603 360K 1% 1mΩ/0603/1% 0603 WALSIN R4 1 0603 15K0 1% Shorted for RT7238B/C 15kΩ/0603/1% for RT7238D (VOUT 1.05V) 0603 WALSIN R5 1 0603 20K0 1% 20kΩ/0603/1% 0603 WALSIN SW1 1 SWITCHES SWITCHES SWITCHES SWITCHES EN1/EN/EN, PG, FB/FB/ILMIT, BS, LX 5 Test PIN Test PIN Test PIN Test PIN U1 1 RT7238B/C/D RT7238B/C/D UQFN-10L 3x3 (FC) RICHTEK RT7238B/C/D GQUF-00 October 2015 6 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. PCB Layout Top View (1st layer) PCB Layout—Inner Side (2nd Layer) RT7238B/C/D GQUF-00 October 2015 7 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. PCB Layout—Inner Side (3rd Layer) Bottom View (4th Layer) RT7238B/C/D GQUF-00 October 2015 8 http://www.richtek.com RT7238B/C/D GQUF Evaluation Board your power partner. More Information For more information, please find the related datasheet or application notes from Richtek website http://www.richtek.com. Important Notice for Richtek Evaluation Board THIS DOCUMENT IS FOR REFERENCE ONLY, NOTHING CONTAINED IN THIS DOCUMENT SHALL BE CONSTRUED AS RICHTEK’S WARRANTY, EXPRESS OR IMPLIED, UNDER CONTRACT, TORT OR STATUTORY, WITH RESPECT TO THE PRESENTATION HEREIN. IN NO EVENT SHALL RICHTEK BE LIABLE T O BUYER OR USER FOR ANY AND ALL DAMAGES INCLUDING WITHOUT LIMITATION TO DIRECT, INDIRECT, SPECIAL, PUNITIVE OR CONSEQUENTIAL DAMAGES. RT7238B/C/D GQUF-00 October 2015 9 http://www.richtek.com