EVB_RT6238AHGQUF

RT6238AHGQUF Evaluation Board your power partner. 8A, 18V, 500kHz, ACOT™ Synchronous Step-Down Converter Purpose The RT6238A is an ACOT control architecture step-down converter, which the input voltage range is from 4.5V to 18V and the output is adjustable from 0.7V to 8V. This document explains the function and use of the RT6238A evaluation board (EVB), and provides information to enable operation, modification of the evaluation board and circuit to suit individual requirements. Table of Contents Purpose ................................................................................................................................................................. 1 Introduction............................................................................................................................................................ 2 Key Performance Summary Table .......................................................................................................................... 2 Bench Test Setup Conditions ................................................................................................................................. 3 Schematic, Bill of Materials & Board Layout ........................................................................................................... 5 More Information.................................................................................................................................................... 8 Important Notice for Richtek Evaluation Board ....................................................................................................... 8 EVB_RT6238AHGQUF-00 August 2016 1 http://www.richtek.com RT6238AHGQUF Evaluation Board your power partner. Introduction General Product Information The RT6238A is a high-performance 500kHz, 8A step-down regulator with internal power switches and synchronous rectifiers. It features quick transient response using its Advanced Constant On-Time (ACOT™) control architecture that provides stable operation with small ceramic output capacitors and without complicated external compensation, among other benefits. With internal 35mΩ switches and 14mΩ synchronous rectifiers, the RT6238A displays excellent efficiency and good behavior across a range of applications, especially for low output voltages and low duty cycles. Cycle-by-cycle current limit provides protection against shorted outputs, input under-voltage lockout, externally-adjustable soft-start, output under- and over-voltage protection, and thermal shutdown provide safe and smooth operation in all operating conditions. The RT6238A is available in the UQFN-14L 2x3 (FC) package, with exposed thermal pad. Product Features     Fast Transient Response Advanced Constant On-Time (ACOT™) Control 4.5V to 18V Input Voltage Range Adjustable Output Voltage from 0.7V to 8V  8A Output Current 35mΩ Internal High-Side N-MOSFET and 14mΩ Internal Low-Side N-MOSFET Steady 500kHz Switching Frequency Up to 95% Efficiency Optimized for All Ceramic Capacitors Externally-Adjustable, Pre-Biased Compatible Soft-Start Cycle-by-Cycle Current Limit Input Under-Voltage Lockout Output Over- and Under-Voltage Protection Power Good Output  Thermal Shutdown          Key Performance Summary Table Key Features Evaluation Board Number : PCB063_V1 Input Voltage Range 12V Max Output Current 8A Default Output Voltage 1.0V Default Marking & Package Type RT6238AHGQUF, UQFN-14L 2x3 (FC) Operation Frequency Steady 500kHz at all loads EVB_RT6238AHGQUF-00 August 2016 2 http://www.richtek.com RT6238AHGQUF Evaluation Board your power partner. Bench Test Setup Conditions Headers Description and Placement Carefully inspect all the components used in the EVB according to the following Bill of Materials table, and then make sure all the components are undamaged and correctly installed. If there is any missing or damaged component, which may occur during transportation, please contact our distributors or e-mail us at evb_service@richtek.com. EVB_RT6238AHGQUF-00 August 2016 3 http://www.richtek.com RT6238AHGQUF Evaluation Board your power partner. Test Points The EVB is provided with the test points and pin names listed in the table below. Test Point/ Pin Name Signal Name Description Input Voltage Power input. The input voltage range is from 4.5V to 18V. Must bypass with a suitably large (≥10µF x 2) ceramic capacitor. EN Enable Enable control input. A logic-high enables the converter; a logic-low forces the IC into shutdown mode reducing the supply current to less than 10µA. Attach this pin to PVCC with a 100k pull-up resistor for automatic start-up. GND Ground Ground. VPVCC Internal Regulator Output Internal regulator output. Connect a 1µF capacitor to GND to stabilize output voltage. PG Power Good Output Power good indicator open-drain output. BOOT Bootstrap Supply Connect a capacitor between the SW and BOOT pins to form a floating supply across the power switch driver. A 0.1µF capacitor is recommended for use. SW Switch Node Connect this pin to an external L-C filter. SS Soft-Start Control An external capacitor should be connected between this pin and GND. VIN Power-Up & Measurement Procedure 1. Apply a 12V nominal input power supply (4.5V < VIN < 18V) to the VIN and GND terminals. 2. Set the jumper at JP1 to connect terminals 2 and 3, connecting EN to VIN through resistor R5, to enable operation. 3. Verify the output voltage (approximately 1V) between VOUT and GND. 4. Connect an external load up to 8A to the VOUT and GND terminals and verify the output voltage and current. Output Voltage Setting Set the output voltage with the resistive divider (R2, R3) between VOUT and GND with the midpoint connected to FB. The output is set by the following formula : VOUT = 0.7 x (1 + R2 ) R3 EVB_RT6238AHGQUF-00 August 2016 4 http://www.richtek.com RT6238AHGQUF Evaluation Board your power partner. Schematic, Bill of Materials & Board Layout EVB Schematic Diagram Bill of Materials Reference Qty Part Number Description Package Manufacturer U1 1 RT6238AHGQUF DC-DC Converter UQFN-14L 2x3 (FC) RICHTEK C1, C12 2 C3, C4 2 C3216X5R1E106KT000E 10µF/25V/X5R C-1210 TDK C5 1 C1608X5R1E105KT000E 1µF/25V/X5R C-0603 TDK C6, C8 2 C1608X7R1H104KT000N 0.1µF/50V/X7R C-0603 TDK C7 1 0603B103K500 10nF/50V/X7R C-0603 WALSIN C9, C10, C11 3 C3225X5R1E226MT000E 22µF/16V/X5R C-1210 TDK R2, R4 2 0603T-1-20K 20k R-0603 旺詮 R3 1 0603T-1-46K4 46.4k R-0603 旺詮 R5 1 0603 100K 1% 100k R-0603 WALSIN L1 1 L2 1 L-744325120 Wurth Elektronik EVB_RT6238AHGQUF-00 NC NC 7443340100 August 2016 1µH 5 http://www.richtek.com RT6238AHGQUF Evaluation Board your power partner. PCB Layout Top View (1st layer) PCB Layout—Inner Side (2nd Layer) EVB_RT6238AHGQUF-00 August 2016 6 http://www.richtek.com RT6238AHGQUF Evaluation Board your power partner. PCB Layout—Inner Side (3rd Layer) Bottom View (4th Layer) EVB_RT6238AHGQUF-00 August 2016 7 http://www.richtek.com RT6238AHGQUF Evaluation Board your power partner. More Information For more information, please refer to the related datasheets 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 TO BUYER OR USER FOR ANY AND ALL DAMAGES INCLUDING WITHOUT LIMITATION TO DIRECT, INDIRECT, SPECIAL, PUNITIVE OR CONSEQUENTIAL DAMAGES. EVB_RT6238AHGQUF-00 August 2016 8 http://www.richtek.com