RT5796AHGJ6 Evaluation Board your power partner. 1.5A, 1MHz, 6V CMCOT Synchronous Step-Down Converter Purpose The RT5796A is a high efficiency synchronous step-down DC/DC converter. Its input voltage range is from 2.5V to 6V and provides an adjustable regulated output voltage from 0.6V to 3.4V while delivering up to 1.5A of output current.This document explains the function and use of the RT5796A 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 ........................................................................................................... 4 More Information.................................................................................................................................................... 5 Important Notice for Richtek Evaluation Board ....................................................................................................... 6 EVB_RT5796AHGJ6-00 May 2016 1 http://www.richtek.com RT5796AHGJ6 Evaluation Board your power partner. Introduction General Product Information The RT5796A is a high efficiency synchronous step-down DC/DC converter. Its input voltage range is from 2.5V to 6V and provides an adjustable regulated output voltage from 0.6V to 3.4V while delivering up to 1.5A of output current. The internal synchronous low on-resistance power switches increase efficiency and eliminate the need for an external Schottky diode. The Current Mode Constant-On-time (CMCOT) operation with internal compensation allows the transient response to be optimized over a wide range of loads and output capacitors. The RT5796A is available in the TSOT-23-6 package. Product Feature Efficiency Up to 95% RDSON 160mΩHS/110mΩ LS VIN Range 2.5V to 6V VREF 0.6V with ±2% Accuracy CMCOT ™ Control Loop Design for Best Transient Response, Robust Loop Stability with Low-ESR (MLCC) COUT Fixed Soft-Start 1.2ms; PGOOD Function in TSOT-23-6 Cycle-by-Cycle Over Current Protection Input Under Voltage Lockout Output Under Voltage Protection (UVP Hiccup) Thermal Shutdown Protection Power Saving at Light Load Key Performance Summary Table Key Features Evaluation Board Number : PCB070_V1 Default Input Voltage 3.3V Max Output Current 1.5A Default Output Voltage 1.2V Default Marking & Package Type RT5796AHGJ6, TSOT-23-6 Operation Frequency Steady 1MHz at all loads EVB_RT5796AHGJ6-00 May 2016 2 http://www.richtek.com RT5796AHGJ6 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 [email protected]. 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) Feedback Voltage Input Feedback Voltage Input. An external resistor divider from the output to GND, tapped to the FB pin, sets the output voltage. VIN Input voltage Supply Voltage Input. The RT5796A operates from a 2.5V to 6V unregulated input. C1 is needed to prevent large voltage spikes from appearing at the input. Quiet ground for controller circuits. GND Ground Power Ground and Quiet Ground for Controller Circuits. PG Power Good Indicator Power Good Indicator. The output of this pin is an open-drain with external pull-up resistor to IN. PG is pulled up to IN when the FB voltage is within 90%, otherwise it is LOW. LX Switch node Switch node. EN Enable Control Input Enable Control Input. FB Power-up & Measurement Procedure 1. Apply a 3.3V nominal input power supply (2.5V < VIN < 6V) to the VIN and GND terminals. 2. Set the jumper at JP1 to connect terminals 2 and 3, connecting EN to VIN. 3. Verify the output voltage (approximately 1.2V) between VOUT and GND. 4. Connect an external load up to 1.5A to the VOUT and GND terminals and verify the output voltage and current. EVB_RT5796AHGJ6-00 May 2016 3 http://www.richtek.com RT5796AHGJ6 Evaluation Board your power partner. 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 = VREF x (1 + R1 / R2) Schematic, Bill of Materials & Board Layout EVB Schematic Diagram Bill of Materials Reference Qty Part Number Description Package Manufacture U1 1 RT5796AHGJ6 DC/DC Converter TSOT-23-6 RICHTEK C1 1 NC C-0603 C2, C3 2 10µF/50V/X5R/1206 C-1206 C4, C5 2 NA C-1210 L1 1 NR8040T1R4N 1.4µH L-NR8040_2 TAIYO YUDEN R1, R2, R3 3 0603 100K 1% 100k R-0603 WALSIN R4 1 NC R-0603 EVB_RT5796AHGJ6-00 C3216X5R1H106KT000N May 2016 4 TDK http://www.richtek.com RT5796AHGJ6 Evaluation Board your power partner. PCB Layout Top View Bottom View EVB_RT5796AHGJ6-00 May 2016 5 http://www.richtek.com RT5796AHGJ6 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 TO BUYER OR USER FOR ANY AND ALL DAMAGES INCLUDING WITHOUT LIMITATION TO DIRECT, INDIRECT, SPECIAL, PUNITIVE OR CONSEQUENTIAL DAMAGES. EVB_RT5796AHGJ6-00 May 2016 6 http://www.richtek.com