EVB_RT6242AHGQUF

RT6242AHGQUF Evaluation Board your power partner. 12A, 18V, 500kHz, ACOT™ Synchronous Step-Down Converter Purpose The RT6242A is an Advanced Constant On-Time (ACOT™) mode step-down converter with the input voltage range from 4.5V to 18V and provides 12A output current. This document explains the function and use of the RT6242A 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_RT6242AHGQUF-00 January 2016 1 http://www.richtek.com RT6242AHGQUF Evaluation Board your power partner. Introduction General Product Information The RT6242A is a synchronous step-down converter with Advanced Constant On-Time (ACOT™) mode control. The ACOT™ provides a very fast transient response with few external components. The low impedance internal MOSFET supports high efficiency operation with wide input voltage range from 4.5V to 18V. The proprietary circuit of the RT6242A enables to support all ceramic capacitors. The output voltage can be adjustable between 0.7V and 8V. The soft-start time is adjustable by an external capacitor. Product Feature                  4.5V to 18V Input Voltage Range 12A Output Current 12mΩInternal High-Side N-MOSFET and 5.4mΩInternal Low-Side N-MOSFET Advanced Constant On-Time Control Fast Transient Response Support All Ceramic Capacitors Up to 95% Efficiency Adjustable Switching Frequency from 300kHz to 700kHz Adjustable Output Voltage from 0.7V to 8V Adjustable Soft-Start Pre-bias Start-Up Adjustable Current Limit from 6A to 16A Cycle-by-Cycle Over Current Protection Power Good Output Input Under-Voltage Lockout Hiccup Mode Under-Voltage Protection Thermal Shutdown Protection Key Performance Summary Table Key Features Evaluation Board Number : PCB055_V1 Default Input Voltage 12V Max Output Current 12A Default Output Voltage 1.4V Default Marking & Package Type RT6242AHGQUF, UQFN-16JL 3x3 (FC) Operation Frequency Steady 500kHz at PWM EVB_RT6242AHGQUF-00 January 2016 2 http://www.richtek.com RT6242AHGQUF Evaluation Board your power partner. Bench Test Setup Conditions Headers Description and Placement 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. Test Points The EVB is provided with the test points and pin names listed in the table below. Test point/ Pin name Signal Comment (expected waveforms or voltage levels on test points) PVCC Internal Regulator Output 5V bias supply output. Connect a 1µF capacitor to ground. SS Soft-Start Time Setting Soft-Start Time Setting. An external capacitor should be connected between this pin and GND. VIN Input voltage Power Input. The input voltage range is from 4.5V to 18V. Must bypass with a suitably large ceramic capacitor. GND Ground Ground. PG Power Good Indicator Power Good Indicator Open-Drain Output. BOOT Bootstrap supply test point Bootstrap. This capacitor is needed to drive the power switch's gate above the supply voltage. It is connected between 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 test point Connect this pin to an external L-C filter. EN 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. EVB_RT6242AHGQUF-00 January 2016 3 http://www.richtek.com RT6242AHGQUF Evaluation Board your power partner. 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 JP2 to connect terminals 2 and 3, connecting EN to VIN through resistor R4, to enable operation. 3. Verify the output voltage (approximately 1.4V) between VOUT and GND. 4. Connect an external load up to 12A to the VOUT and GND terminals and verify the output voltage and current. Output Voltage Setting Set the output voltage with the resistive divider (R1, R2) between VOUT and GND with the midpoint connected to FB. The output is set by the following formula : VOUT = VFB × (1 + R1 ) R2 EVB_RT6242AHGQUF-00 January 2016 4 http://www.richtek.com RT6242AHGQUF Evaluation Board your power partner. Schematic, Bill of Materials & Board Layout EVB Schematic Diagram Bill of Materials Reference Qty Part Number Description Package Manufacture U1 1 RT6242AHGQUF DC/DC Converter UQFN-16JL 3x3 (FC) RICHTEK C1 1 NA C-0603 C3, C4 2 UMK325BJ106MM 10µF/50V/X5R/1210 C-1210 TAIYO YUDEN C5 1 C1608X5R1E105KT000E 1µF/25V/X5R/0603 C-0603 TDK C6, C8, C12 3 C1608X7R1H104KT000N 0.1µF/50V/X7R/0603 C-0603 TDK C7 1 0603B103K500 10nF/50V/X7R/0603 C-0603 WALSIN C9 1 C3225X5R1E226MT 22µF/25V/X5R/1210 C-1210 TDK C10, C11 2 C3225X5R1E226MT 22µF/25V/X5R/1210 C-1210 TDK L1 1 7443340100 1.0µH/17A 8.4 x 7.9 x 7.2mm Wurth Elektronik L2 1 NA R1, R2 2 20k R-0603 R6 1 150k R-0603 R7 1 66k R-0603 R3, R4 2 100k R-0603 EVB_RT6242AHGQUF-00 January 2016 5 http://www.richtek.com RT6242AHGQUF Evaluation Board your power partner. PCB Layout Top View (1st layer) PCB Layout—Inner Side (2nd Layer) EVB_RT6242AHGQUF-00 January 2016 6 http://www.richtek.com RT6242AHGQUF Evaluation Board your power partner. PCB Layout—Inner Side (3rd Layer) Bottom View (4th Layer) EVB_RT6242AHGQUF-00 January 2016 7 http://www.richtek.com RT6242AHGQUF 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. EVB_RT6242AHGQUF-00 January 2016 8 http://www.richtek.com