overview

1. Purpose

<p class="MsoNormal">The RT5797A is a high efficiency synchronous step-down DC-DC converter. Its input voltage range is from 2.7V to 6V and provides an adjustable regulated output voltage from 0.6V to 3.4V while delivering up to 3A of output current. This document explains the function and use of the RT5797A evaluation board (EVB), and provides information to enable operation, modification of the evaluation board and circuit to suit individual requirements.</p>

2. Introduction

<h3>General Product Information</h3> <p class="bady">The RT5797A is a high efficiency synchronous step-down DC-DC converter. Its input voltage range is from 2.7V to 6V and provides an adjustable regulated output voltage from 0.6V to 3.4V while delivering up to 3A of output current. The internal synchronous low on-resistance power switches increase efficiency and eliminate the need for an external Schottky diode. The RT5797A is available in the WDFN-8SL 2x2 packages. </p>

3. Product Feature

<ul> <li>Efficiency Up to 95% </li> <li>R_DS(ON) 100mΩ HS / 70mΩ LS</li> <li>V_IN Range 2.7V to 6V</li> <li>V_REF 0.6V with ±1% Accuracy at 25℃</li> <li>CMCOT^TM Control Loop Design for Best Transient Response, Robust Loop Stability with Low-ESR (MLCC) C_OUT</li> <li>Fixed Soft-Start 1.2ms</li> <li>Power Saving in Light Load</li> </ul>

4. Key Performance Summary Table

<div> <table class="MsoTableLightListAccent2" border="1" cellspacing="0" cellpadding="0" width="680" style="width:510.2pt;border-collapse:collapse;border:none"> <tr style="height:17.0pt"> <td width="34%" style="width:34.94%;border:solid #009EB8 1.0pt;background: #009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Key Features</p> </td> <td width="65%" style="width:65.06%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">Evaluation Board Number : PCB103_V1</p> </td> </tr> <tr style="height:17.0pt"> <td width="34%" style="width:34.94%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Default Input Voltage</p> </td> <td width="65%" style="width:65.06%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">5V</p> </td> </tr> <tr style="height:17.0pt"> <td width="34%" style="width:34.94%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Max Output Current</p> </td> <td width="65%" style="width:65.06%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">3A</p> </td> </tr> <tr style="height:17.0pt"> <td width="34%" style="width:34.94%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Default Output Voltage</p> </td> <td width="65%" style="width:65.06%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">1.2V</p> </td> </tr> <tr style="height:17.0pt"> <td width="34%" style="width:34.94%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Default Marking & Package Type</p> </td> <td width="65%" style="width:65.06%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">RT5797AHGQWA, WDFN-8SL 2x2</p> </td> </tr> <tr style="height:17.0pt"> <td width="34%" style="width:34.94%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Operation Frequency</p> </td> <td width="65%" style="width:65.06%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">1MHz in CCM mode</p> </td> </tr> </table> </div>

5. Bench Test Setup Conditions

<h3>Headers Description and Placement</h3> <p class="2"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image001_en.png"><img width="431" height="310" id="圖片 2" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image001_en.png" alt="Technical Document Image Preview" /></a></p> <p class="2">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 <a href="mailto:evb_service@richtek.com" class="link">evb_service@richtek.com</a>.</p>

6. Test Points

<p class="MsoNormal">The EVB is provided with the test points and pin names listed in the table below.</p> <table class="MsoTableLightListAccent2" border="1" cellspacing="0" cellpadding="0" width="680" style="width:510.2pt;margin-left:5.4pt;border-collapse:collapse; border:none"> <thead> <tr style="height:1.0cm"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;background: #009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="23CxSpFirst">Test point/</p> <p class="23CxSpMiddle">Pin name</p> </td> <td width="23%" style="width:23.18%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="23CxSpMiddle">Signal</p> </td> <td width="62%" style="width:62.56%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="23CxSpLast">Comment (expected waveforms or voltage levels on test points)</p> </td> </tr> </thead> <tr style="height:39.7pt"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt"> <p class="ListParagraph1CxSpFirst">FB</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt"> <p class="ListParagraph1CxSpLast">Feedback Voltage Input</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt"> <p class="MsoNormal">An external resistor divider from the output to SGND, tapped to the FB pin, sets the output voltage. keep away from high current loops and swithing voltages.</p> </td> </tr> <tr style="height:39.7pt"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt"> <p class="ListParagraph1">PGOOD</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt"> <p class="MsoNormal">Power Good Indicator</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt"> <p class="MsoNormal">The output of this pin is an open-drain with external pull-up resistor. PG is pulled up when the FB voltage is within 90%, otherwise it is LOW.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">VIN</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpMiddle">Supply Voltage Input</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">The RT5797A operates from a 2.7V to 6V input.</p> </td> </tr> <tr style="height:1.0cm"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="ListParagraph1CxSpFirst">PGND, GND GND1, GND2</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="ListParagraph1CxSpMiddle">Power Ground</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="ListParagraph1CxSpLast">Power ground. The exposed pad must be soldered to a large PCB and connected to PGND for maximum thermal dissipation.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">NC</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">No Internal Connection</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">No internal connection.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">LX</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Switch Node</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Switch node.</p> </td> </tr> <tr style="height:1.0cm"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="ListParagraph1">EN</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">Enable Control Input</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">Enable control input. A logic-high enables the converter; a logic-low forces the device into shutdown mode.</p> </td> </tr> <tr style="height:1.0cm"> <td width="14%" style="width:14.26%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="ListParagraph1">SGND</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">Signal Ground</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">Signal ground of the FB network. SGND should be connected to PGND close to the IC PGND pins.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.26%;border-top:none;border-left:solid #009EB8 1.0pt; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">VO</p> </td> <td width="23%" style="width:23.18%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Output voltage</p> </td> <td width="62%" style="width:62.56%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Output voltage.</p> </td> </tr> </table>

7. Power-up & Measurement Procedure

<p class="MsoListParagraph">1. Apply a 5V nominal input power supply (2.7V < V_IN < 6V) to the VIN and GND terminals.</p> <p class="MsoListParagraph">2. Set the jumper at JP1 to connect terminals 2 and 3, connecting EN to VIN through resistor R4 (100kΩ). The Enable pin can connected to VIN directly as well to enable operation.</p> <p class="MsoListParagraph">3. Verify the output voltage (approximately 1.2V) between VOUT and GND.</p> <p class="MsoListParagraph">4. Connect an external load up to 3A to the VOUT and GND terminals and verify the output voltage and current.</p>

8. Output Voltage Setting

<p class="MsoNormal">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 : </p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image002_en.png"><img width="141" height="48" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image002_en.png" alt="Technical Document Image Preview" /></a></p> <p class="MsoNormal">The placement of the resistive divider should be within 5mm of the FB pin. The resistance of R2 is suggested between 10kΩ and 150kΩ to minimize power consumption, and noise pick-up at the FB pin. The resistance of R1 can then be obtained as below :</p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image003_en.png"><img width="145" height="48" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image003_en.png" alt="Technical Document Image Preview" /></a></p> <p class="MsoNormal">For better output voltage accuracy, divider resistors (R1 and R2) should have tolerance of ±1% tolerance or better.</p>

9. Schematic, Bill of Materials & Board Layout

<h3>EVB Schematic Diagram</h3> <p class="MsoNormal">RT5797AHGQW demo board : V_IN 5V, V_OUT 1.2V / 3A</p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image004_en.png"><img border="0" width="680" height="253" id="圖片 20" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image004_en.png" alt="Technical Document Image Preview" /></a></p> <p class="MsoNormal">Note: </p> <p class="MsoListParagraph">1. Do not hot-plug a live 5V supply to the board; if hot-plugging is required, add ~100µF electrolytic capacitor at the input.</p> <p class="MsoNormal">A small feedforward capacitor (C1) can be introduced into the feedback network to speed up the transient response of high output voltage circuits. Adding C1 can also improve the light load PSM switching behavior. The feedforward capacitor is added across the upper FB divider. </p> <p class="MsoNormal">To optimize transient response, C1value is chosen so that the gain and phase boost of the feedback network increases the bandwidth of the converter, while still maintaining an acceptable phase margin. Generally, larger C1values provide higher bandwidth, but may result in an unacceptable phase margin or instability.</p>

10. Measurement Results

<table class="MsoNormalTable" border="1" cellspacing="0" cellpadding="0" width="684" style="margin-left:4.0pt;border-collapse:collapse;border:none"> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Output ripple measurement at V_IN = 5V 10mA load</p> <p class="MsoNormal">Cyan : V-SW; Blue : V_OUT</p> </td> <td width="342" valign="top" style="width:256.55pt;border:solid windowtext 1.0pt; border-left:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Output ripple measurement at V_IN = 5V 3A load</p> <p class="MsoNormal">Cyan : V-SW; Blue : V_OUT</p> </td> </tr> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image005_en.jpg"><img border="0" width="302" height="227" id="圖片 18" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image005_en.jpg" alt="TEK00076" /></a></p> </td> <td width="342" valign="top" style="width:256.55pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image006_en.jpg"><img border="0" width="302" height="227" id="圖片 17" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image006_en.jpg" alt="TEK00075" /></a></p> </td> </tr> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Output ripple at 10mA load : 19.8mVpp, PSM mode</p> </td> <td width="342" valign="top" style="width:256.55pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Output ripple at 3A load : 13.4mVpp </p> <p class="MsoNormal">PWM frequency is 1.062kHz. </p> </td> </tr> </table> <table class="MsoNormalTable" border="1" cellspacing="0" cellpadding="0" width="684" style="margin-left:4.0pt;border-collapse:collapse;border:none"> <tr style="height:36.05pt"> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:36.05pt"> <p class="MsoNormal">Dynamic load 0.01A to 2.2A load step</p> <p class="MsoNormal">Blue : V_OUT; Green : load current step</p> </td> <td width="342" valign="top" style="width:256.55pt;border:solid windowtext 1.0pt; border-left:none;padding:0cm 5.4pt 0cm 5.4pt;height:36.05pt"> <p class="MsoNormal">Dynamic load 1A to 2.6A load step </p> <p class="MsoNormal">Blue : V_OUT; Green : load current step</p> </td> </tr> <tr style="height:179.7pt"> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt;height:179.7pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image007_en.jpg"><img border="0" width="302" height="227" id="圖片 16" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image007_en.jpg" alt="TEK00068" /></a></p> </td> <td width="342" valign="top" style="width:256.55pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:179.7pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image008_en.jpg"><img border="0" width="302" height="227" id="圖片 15" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image008_en.jpg" alt="TEK00069" /></a></p> </td> </tr> <tr style="height:1.0cm"> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">Overshoot : 21mV, Undershoot : 33mV in light load mode</p> </td> <td width="342" valign="top" style="width:256.55pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">Overshoot : 22mV, Undershoot : 24mV </p> </td> </tr> </table> <div> <table class="MsoTableGrid" border="1" cellspacing="0" cellpadding="0" style="border-collapse:collapse;border:none"> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">OCP measurement : Dynamic load close to OCP </p> <p class="MsoNormal">Blue: V_OUT; Purple: Pgood; Green: Iout</p> </td> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-left:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">OCP measurement : Full output short circuit </p> <p class="MsoNormal">Blue: V_OUT; Purple: Pgood; Green: Iout</p> </td> </tr> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image009_en.jpg"><img border="0" width="302" height="227" id="圖片 12" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image009_en.jpg" alt="TEK00070" /></a></p> </td> <td width="342" valign="top" style="width:256.5pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image010_en.jpg"><img border="0" width="302" height="227" id="圖片 11" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image010_en.jpg" alt="TEK00071" /></a></p> </td> </tr> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Vout drops at 4A peak load.</p> </td> <td width="342" valign="top" style="width:256.5pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Frequency reduction, hiccup mode at 4.24A peak load current</p> </td> </tr> </table> </div> <div> <table class="MsoTableGrid" border="1" cellspacing="0" cellpadding="0" style="border-collapse:collapse;border:none"> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Start-up measurement from Enable : <br /> EN pin 7 low – high</p> <p class="MsoNormal">Cyan : V-Enable; Blue:V_OUT; Purple : Pgood; Green : I_OUT</p> </td> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-left:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Start-up measurement from VIN : </p> <p class="MsoNormal">Cyan : V_IN; Blue : V_OUT; Purple : Pgood; Green : I_OUT</p> </td> </tr> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image011_en.jpg"><img border="0" width="302" height="227" id="圖片 10" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image011_en.jpg" alt="TEK00073" /></a></p> </td> <td width="342" valign="top" style="width:256.5pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image012_en.jpg"><img border="0" width="302" height="227" id="圖片 9" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image012_en.jpg" alt="TEK00074" /></a></p> </td> </tr> <tr> <td width="342" valign="top" style="width:256.5pt;border:solid windowtext 1.0pt; border-top:none;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Start-up time 1.24msec. Soft-start 1.1msec</p> </td> <td width="342" valign="top" style="width:256.5pt;border-top:none;border-left: none;border-bottom:solid windowtext 1.0pt;border-right:solid windowtext 1.0pt; padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">V_IN > 2.24V initiates start-up. </p> </td> </tr> </table> </div>

11. Efficiency Measurements

<p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image013_en.png"><img border="0" width="635" height="226" id="圖片 8" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image013_en.png" alt="Technical Document Image Preview" /></a></p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image014_en.jpg"><img border="0" width="346" height="250" id="圖片 7" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image014_en.jpg" alt="Technical Document Image Preview" /></a><br /> <br /> <a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image015_en.jpg"><img border="0" width="346" height="260" id="圖片 6" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image015_en.jpg" alt="Technical Document Image Preview" /></a></p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image016_en.png"><img border="0" width="639" height="225" id="圖片 5" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image016_en.png" alt="Technical Document Image Preview" /></a><br /> <br /> <a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image017_en.jpg"><img border="0" width="346" height="250" id="圖片 4" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image017_en.jpg" alt="Technical Document Image Preview" /></a><br /> <br /> <a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image018_en.jpg"><img border="0" width="346" height="261" id="圖片 1" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image018_en.jpg" alt="Technical Document Image Preview" /></a></p>

12. Bill of Materials

<table class="MsoTableLightListAccent2" border="1" cellspacing="0" cellpadding="0" width="680" style="margin-left:5.4pt;border-collapse:collapse;border:none"> <thead> <tr style="height:17.0pt"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;background: #009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Reference</p> </td> <td width="5%" style="width:5.34%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Qty</p> </td> <td width="25%" style="width:25.1%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Part Number</p> </td> <td width="21%" style="width:21.4%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Description</p> </td> <td width="16%" style="width:16.2%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Package</p> </td> <td width="14%" style="width:14.8%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Manufacturer</p> </td> </tr> </thead> <tr style="height:17.0pt"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">U1</p> </td> <td width="5%" style="width:5.34%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">1</p> </td> <td width="25%" style="width:25.1%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">RT5797AHGQWA</p> </td> <td width="21%" style="width:21.4%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">DC-DC Converter</p> </td> <td width="16%" style="width:16.2%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">WDFN-8SL 2x2</p> </td> <td width="14%" style="width:14.8%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">Richtek</p> </td> </tr> <tr style="height:17.0pt"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C1</p> </td> <td width="5%" style="width:5.34%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">1</p> </td> <td width="25%" style="width:25.1%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> </td> <td width="21%" style="width:21.4%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">NC</p> </td> <td width="16%" style="width:16.2%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C-0603</p> </td> <td width="14%" style="width:14.8%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> </td> </tr> <tr style="height:17.0pt"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C2, C3, C4</p> </td> <td width="5%" style="width:5.34%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">3</p> </td> <td width="25%" style="width:25.1%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">GRM31CR61C226KE15L</p> </td> <td width="21%" style="width:21.4%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">22µF/16V/X5R/1206</p> </td> <td width="16%" style="width:16.2%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C-1206</p> </td> <td width="14%" style="width:14.8%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">muRata</p> </td> </tr> <tr style="height:17.0pt"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C5</p> </td> <td width="5%" style="width:5.34%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">1</p> </td> <td width="25%" style="width:25.1%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> </td> <td width="21%" style="width:21.4%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">NC</p> </td> <td width="16%" style="width:16.2%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C-1206</p> </td> <td width="14%" style="width:14.8%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> </td> </tr> <tr style="height:17.0pt"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C6</p> </td> <td width="5%" style="width:5.34%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">1</p> </td> <td width="25%" style="width:25.1%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">GRM188R71H104KA93D</p> </td> <td width="21%" style="width:21.4%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">100nF/50V/X7R/0603</p> </td> <td width="16%" style="width:16.2%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">C-0603</p> </td> <td width="14%" style="width:14.8%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">muRata</p> </td> </tr> <tr style="height:1.0cm"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">L1</p> </td> <td width="5%" style="width:5.34%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">1</p> </td> <td width="25%" style="width:25.1%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">7447714015</p> </td> <td width="21%" nowrap style="width:21.4%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">1.5µH</p> </td> <td width="16%" style="width:16.2%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">10x10x5mm</p> </td> <td width="14%" style="width:14.8%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="MsoNormal">WURTH ELEKTRONIK</p> </td> </tr> <tr style="height:17.0pt"> <td width="17%" style="width:17.16%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">R1, R2, R3, R4</p> </td> <td width="5%" style="width:5.34%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">4</p> </td> <td width="25%" style="width:25.1%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">WR06X1003FTL</p> </td> <td width="21%" nowrap style="width:21.4%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">100k/0603</p> </td> <td width="16%" style="width:16.2%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">R-0603</p> </td> <td width="14%" style="width:14.8%;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="MsoNormal">WALSIN</p> </td> </tr> </table>

13. PCB Layout

<p class="23CxSpMiddle"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image019_en.jpg"><img border="0" width="492" height="352" id="圖片 13" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image019_en.jpg" alt="Technical Document Image Preview" /></a></p> <p class="23CxSpMiddle">Top View (1^st layer)</p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image020_en.jpg"><img border="0" width="491" height="353" id="圖片 3" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image020_en.jpg" alt="Technical Document Image Preview" /></a></p> <p class="10">PCB Layout—Inner Side (2^nd Layer)</p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image021_en.jpg"><img border="0" width="492" height="353" id="圖片 14" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image021_en.jpg" alt="Technical Document Image Preview" /></a></p> <p class="10">PCB Layout—Inner Side (3^rd Layer)</p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image022_en.jpg"><img border="0" width="492" height="352" id="圖片 19" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rt5797ahgqwa/html-images/image022_en.jpg" alt="Technical Document Image Preview" /></a></p> <p class="23">Bottom View (4^th Layer)</p>