overview

1. General Description

<p class="bady">The Evaluation Board user guide describes the operational use of the RTQ2531W evaluation board as a reference design for demonstration and evaluation of the RTQ2531W, a low-noise, high accuracy, low-dropout (LDO) linear regulator.</p> <p class="bady">Included in this user guide are setup and operating instructions, thermal and layout guidelines, a printed circuit board (PCB) layout, a schematic diagram, and a bill of materials (BOM). For more detail information, please refer to the RTQ2531W datasheet</p>

2. Performance Specification Summary

<p class="bady">Summary of the RTQ2531W Evaluation Board performance specificiaiton is provided in Table 1. The ambient temperature is 25°C.</p> <p class="MsoNormal">Table 1. RTQ2531W Evaluation Board Performance Specification Summary</p> <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="184" style="width:138.35pt;border:solid #009EB8 1.0pt;background: #009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Specification</p> </td> <td width="304" style="width:228.05pt;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpMiddle">Test Conditions</p> </td> <td width="42" style="width:31.8pt;border:solid #009EB8 1.0pt;border-left:none; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpMiddle">Min</p> </td> <td width="42" style="width:31.8pt;border:solid #009EB8 1.0pt;border-left:none; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpMiddle">Typ</p> </td> <td width="42" style="width:31.8pt;border:solid #009EB8 1.0pt;border-left:none; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpMiddle">Max</p> </td> <td width="65" style="width:48.4pt;border:solid #009EB8 1.0pt;border-left:none; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpLast">Unit</p> </td> </tr> <tr style="height:17.0pt"> <td width="184" style="width:138.35pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Input Voltage Range</p> </td> <td width="304" style="width:228.05pt;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="42" style="width:31.8pt;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">1.7</p> </td> <td width="42" style="width:31.8pt;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">3.8</p> </td> <td width="42" style="width:31.8pt;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">5.5</p> </td> <td width="65" style="width:48.4pt;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">V</p> </td> </tr> <tr style="height:17.0pt"> <td width="184" style="width:138.35pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Output Current</p> </td> <td width="304" style="width:228.05pt;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="42" style="width:31.8pt;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">0</p> </td> <td width="42" style="width:31.8pt;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">--</p> </td> <td width="42" style="width:31.8pt;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">0.5</p> </td> <td width="65" style="width:48.4pt;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">A</p> </td> </tr> <tr style="height:17.0pt"> <td width="184" style="width:138.35pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Output Voltage Range</p> </td> <td width="304" style="width:228.05pt;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="42" style="width:31.8pt;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">0.6</p> </td> <td width="42" style="width:31.8pt;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">3.3</p> </td> <td width="42" style="width:31.8pt;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">5.3</p> </td> <td width="65" style="width:48.4pt;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">V</p> </td> </tr> <tr style="height:39.7pt"> <td width="184" style="width:138.35pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:39.7pt"> <p class="ListParagraph1CxSpFirst">Line Regulation</p> </td> <td width="304" style="width:228.05pt;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="ListParagraph1CxSpMiddle">1.7V ≤ V_IN ≤ 5.5V for V_OUT ≤ 1.4V,</p> <p class="ListParagraph1CxSpMiddle">V_OUT + 0.3V ≤ V_IN ≤ 5.5V for V_OUT ≥ 1.4V,</p> <p class="ListParagraph1CxSpMiddle">I_OUT = 200mA</p> </td> <td width="42" style="width:31.8pt;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="ListParagraph1CxSpMiddle">--</p> </td> <td width="42" style="width:31.8pt;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="ListParagraph1CxSpMiddle">0.04</p> </td> <td width="42" style="width:31.8pt;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="ListParagraph1CxSpMiddle">--</p> </td> <td width="65" style="width:48.4pt;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">%/V</p> </td> </tr> <tr style="height:17.0pt"> <td width="184" style="width:138.35pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1CxSpFirst">Load Regulation</p> </td> <td width="304" style="width:228.05pt;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">0.1mA ≤ I_OUT ≤ 500mA</p> </td> <td width="42" style="width:31.8pt;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">--</p> </td> <td width="42" style="width:31.8pt;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">0.02</p> </td> <td width="42" style="width:31.8pt;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">--</p> </td> <td width="65" style="width:48.4pt;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">%/A</p> </td> </tr> <tr style="height:1.0cm"> <td width="184" style="width:138.35pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="ListParagraph1CxSpFirst">Load Transient Response</p> </td> <td width="304" style="width:228.05pt;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">I_OUT = 50mA to 500mA to 50mA,</p> <p class="ListParagraph1CxSpMiddle">t_RISE = t_FALL = 1µs</p> </td> <td width="42" style="width:31.8pt;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">--</p> </td> <td width="42" style="width:31.8pt;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">50</p> </td> <td width="42" style="width:31.8pt;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">--</p> </td> <td width="65" style="width:48.4pt;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">mV/P-P</p> </td> </tr> </table> </div>

3. Power-up Procedure

<h3>Suggestion Required Equipments</h3> <ul> <li>RTQ2531W Evaluation Board</li> <li>DC power supply capable of at least 5.5V and 500mA</li> <li>Electronic load capable of 500mA</li> <li>Function Generator</li> <li>Oscilloscope</li> </ul>

4. Quick Start Procedures

<p class="bady">The Evaluation Board is fully assembled and tested. Follow the steps below to verify board operation. Do not turn on supplies until all connections are made. When measuring the output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the output voltage ripple by touching the probe tip and groundring directly across the last output capacitor. </p>

5. Proper measurement equipment setup and follow the procedure below.

<p class="MsoNormal">1) With power off, connect the input power supply to VIN and GND pins.</p> <p class="MsoNormal">2) With power off, connect the electronic load between the VOUT and nearest GND pins. </p> <p class="MsoNormal">3) Turn on the power supply at the input. Make sure that the input voltage does not exceeds 6V on the Evaluation Board.</p> <p class="MsoNormal">4) Check for the proper output voltage using a voltmeter. </p> <p class="MsoNormal">5) Once the proper output voltage is established, adjust the load within the operating ranges and observe the output voltage regulation, quiescent current, dropout voltage, PSRR, noise and other performance.</p>

6. Detailed Description of Hardware

<h3>Headers Description and Placement</h3> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image001_en.png"><img width="491" height="351" id="圖片 4" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image001_en.png" alt="Technical Document Image Preview" /></a></p> <p class="MsoNormal">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>

7. 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:1.85pt;border-collapse:collapse; border:none"> <thead> <tr style="height:1.0cm"> <td width="14%" style="width:14.64%;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="85%" style="width:85.36%;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt;height:1.0cm"> <p class="23CxSpLast">Function</p> </td> </tr> </thead> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">VIN</p> </td> <td width="85%" style="width:85.36%;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">Supply input pin.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">GND</p> </td> <td width="85%" style="width:85.36%;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">System ground pin.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">EN</p> </td> <td width="85%" style="width:85.36%;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">Enable sense pin.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">POK</p> </td> <td width="85%" style="width:85.36%;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">Power-OK sense pin.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">VOUT</p> </td> <td width="85%" style="width:85.36%;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 of the regulator.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">EN1</p> </td> <td width="85%" style="width:85.36%;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">User can decide EN pin connected to high or low.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">POK1</p> </td> <td width="85%" style="width:85.36%;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">User can decide POK pin connected to high or low.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">JP2</p> </td> <td width="85%" style="width:85.36%;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">Short to by-pass resistor R3.</p> </td> </tr> <tr style="height:17.0pt"> <td width="14%" style="width:14.64%;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:17.0pt"> <p class="ListParagraph1">JP7</p> </td> <td width="85%" style="width:85.36%;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">Pins to change resistor divider.</p> </td> </tr> </table>

8. Bill of Materials

<div> <table class="TableNormal" border="1" cellspacing="0" cellpadding="0" width="680" style="width:510.2pt;border-collapse:collapse;border:none"> <tr style="height:17.0pt"> <td width="680" colspan="7" style="width:510.2pt;border:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">V_IN = 1.7V to 5.5V, V_OUT = 0.6V to 5.3V, I_OUT = 500mA</p> </td> </tr> <tr style="height:17.0pt"> <td width="76" style="width:57.2pt;border:solid #009EB8 1.0pt;border-top:none; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">Reference</p> </td> <td width="37" style="width:27.95pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">Count</p> </td> <td width="166" style="width:124.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">Part Number</p> </td> <td width="99" style="width:74.45pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">Value</p> </td> <td width="122" style="width:91.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">Description</p> </td> <td width="95" style="width:71.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">Package</p> </td> <td width="85" style="width:63.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="TableParagraph">Manufacturer</p> </td> </tr> <tr style="height:17.0pt"> <td width="76" style="width:57.2pt;border:solid #009EB8 1.0pt;border-top:none; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">U1</p> </td> <td width="37" style="width:27.95pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">1</p> </td> <td width="166" style="width:124.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">RTQ2531WGQW</p> </td> <td width="99" style="width:74.45pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">RTQ2531W</p> </td> <td width="122" style="width:91.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">LDO</p> </td> <td width="95" style="width:71.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">WDFN-8SL 2x2</p> </td> <td width="85" style="width:63.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">RICHTEK</p> </td> </tr> <tr style="height:1.0cm"> <td width="76" style="width:57.2pt;border:solid #009EB8 1.0pt;border-top:none; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">C6</p> </td> <td width="37" style="width:27.95pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">1</p> </td> <td width="166" style="width:124.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">0603B103K500CT</p> </td> <td width="99" style="width:74.45pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">10nF</p> </td> <td width="122" style="width:91.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">Capacitor, ceramic,</p> <p class="MsoNormal">50V, X7R</p> </td> <td width="95" style="width:71.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">0603</p> </td> <td width="85" style="width:63.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">WALSIN</p> </td> </tr> <tr style="height:1.0cm"> <td width="76" style="width:57.2pt;border:solid #009EB8 1.0pt;border-top:none; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">C11, C12</p> </td> <td width="37" style="width:27.95pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">2</p> </td> <td width="166" style="width:124.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">GRM21BR71A106KE51L</p> </td> <td width="99" style="width:74.45pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">10μF</p> </td> <td width="122" style="width:91.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">Capacitor, ceramic,</p> <p class="MsoNormal">10V, X7R</p> </td> <td width="95" style="width:71.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">0805</p> </td> <td width="85" style="width:63.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:1.0cm"> <p class="MsoNormal">MURATA</p> </td> </tr> <tr style="height:17.0pt"> <td width="76" style="width:57.2pt;border:solid #009EB8 1.0pt;border-top:none; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">R1</p> </td> <td width="37" style="width:27.95pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">1</p> </td> <td width="166" style="width:124.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">WR06X2673FTL</p> </td> <td width="99" style="width:74.45pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">267k</p> </td> <td width="122" style="width:91.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">Resistor, chip</p> </td> <td width="95" style="width:71.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">0603</p> </td> <td width="85" style="width:63.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">WALSIN</p> </td> </tr> <tr style="height:17.0pt"> <td width="76" style="width:57.2pt;border:solid #009EB8 1.0pt;border-top:none; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">R2</p> </td> <td width="37" style="width:27.95pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">1</p> </td> <td width="166" style="width:124.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">WR06X5902FTL</p> </td> <td width="99" style="width:74.45pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">59k</p> </td> <td width="122" style="width:91.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">Resistor, chip</p> </td> <td width="95" style="width:71.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">0603</p> </td> <td width="85" style="width:63.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:17.0pt"> <p class="MsoNormal">WALSIN</p> </td> </tr> <tr style="height:39.7pt"> <td width="76" style="width:57.2pt;border:solid #009EB8 1.0pt;border-top:none; padding:0cm 0cm 0cm 0cm;height:39.7pt"> <p class="MsoNormal">REN1, REN2, REN3 </p> </td> <td width="37" style="width:27.95pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:39.7pt"> <p class="MsoNormal">3</p> </td> <td width="166" style="width:124.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:39.7pt"> <p class="MsoNormal">WR06X1003FTL</p> </td> <td width="99" style="width:74.45pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:39.7pt"> <p class="MsoNormal">100k</p> </td> <td width="122" style="width:91.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:39.7pt"> <p class="MsoNormal">Resistor, chip</p> </td> <td width="95" style="width:71.15pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:39.7pt"> <p class="MsoNormal">0603</p> </td> <td width="85" style="width:63.65pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 0cm 0cm 0cm;height:39.7pt"> <p class="MsoNormal">WALSIN</p> </td> </tr> </table> </div>

9. Typical Applications

<h3>EVB Schematic Diagram</h3> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image002_en.jpg"><img border="0" width="695" height="246" id="圖片 5" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image002_en.jpg" alt="Technical Document Image Preview" /></a></p> <p class="MsoNormal">1. The capacitance values of the input and output capacitors will influence the input and output voltage ripple. </p> <p class="MsoNormal">2. MLCC capacitors have degrading capacitance at DC bias voltage, and especially smaller size MLCC capacitors will have much lower capacitance. </p>

10. Measure Result

<table class="MsoNormalTable" border="1" cellspacing="0" cellpadding="0" style="margin-left:26.35pt;border-collapse:collapse;border:none"> <tr> <td width="307" valign="top" style="width:230.05pt;border:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Power Up Response</p> </td> <td width="307" style="width:230.35pt;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Dropout Voltage vs. Output Current</p> </td> </tr> <tr style="height:166.0pt"> <td width="307" style="width:230.05pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:166.0pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image003_en.jpg"><img border="0" width="293" height="197" id="圖片 15" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image003_en.jpg" alt="Technical Document Image Preview" /></a></p> </td> <td width="307" style="width:230.35pt;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:166.0pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image004_en.jpg"><img border="0" width="268" height="206" id="圖片 26" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image004_en.jpg" alt="Technical Document Image Preview" /></a></p> </td> </tr> <tr> <td width="307" valign="top" style="width:230.05pt;border:solid #009EB8 1.0pt; border-top:none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Quiescent Current</p> </td> <td width="307" valign="top" style="width:230.35pt;border-top:none;border-left: none;border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Line Transient Response</p> </td> </tr> <tr style="height:172.25pt"> <td width="307" style="width:230.05pt;border-top:none;border-left:solid #009EB8 1.0pt; border-bottom:solid #007589 1.0pt;border-right:solid #007589 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:172.25pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image005_en.jpg"><img border="0" width="273" height="213" id="圖片 6" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image005_en.jpg" alt="Technical Document Image Preview" /></a></p> </td> <td width="307" style="width:230.35pt;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:172.25pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image006_en.jpg"><img border="0" width="292" height="194" id="圖片 13" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image006_en.jpg" alt="Technical Document Image Preview" /></a></p> </td> </tr> <tr> <td width="307" valign="top" style="width:230.05pt;border:solid #009EB8 1.0pt; border-top:none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Load Transient Response</p> </td> <td width="307" style="width:230.35pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">PSRR vs. Frequency</p> </td> </tr> <tr style="height:177.15pt"> <td width="307" style="width:230.05pt;border-top:none;border-left:solid #009EB8 1.0pt; border-bottom:solid #009EB8 1.0pt;border-right:solid #007589 1.0pt; padding:0cm 5.4pt 0cm 5.4pt;height:177.15pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image007_en.jpg"><img border="0" width="305" height="206" id="圖片 12" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image007_en.jpg" alt="Technical Document Image Preview" /></a></p> </td> <td width="307" style="width:230.35pt;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:177.15pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image008_en.jpg"><img border="0" width="274" height="216" id="圖片 27" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image008_en.jpg" alt="Technical Document Image Preview" /></a></p> </td> </tr> </table> <table class="MsoNormalTable" border="1" cellspacing="0" cellpadding="0" style="margin-left:26.35pt;border-collapse:collapse;border:none"> <tr> <td width="307" style="width:230.2pt;border:solid #009EB8 1.0pt;background: #009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Output Noise vs. Frequency</p> </td> <td width="307" style="width:230.35pt;border:solid #009EB8 1.0pt;border-left: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">OCP</p> </td> </tr> <tr style="height:184.15pt"> <td width="307" style="width:230.2pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 1.4pt 0cm 1.4pt;height:184.15pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image009_en.jpg"><img border="0" width="293" height="239" id="圖片 24" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image009_en.jpg" alt="Technical Document Image Preview" /></a></p> </td> <td width="307" style="width:230.35pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; padding:0cm 1.4pt 0cm 1.4pt;height:184.15pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image010_en.png"><img border="0" width="293" height="211" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image010_en.png" alt="Technical Document Image Preview" /></a></p> </td> </tr> <tr> <td width="307" style="width:230.2pt;border:solid #009EB8 1.0pt;border-top: none;background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> <p class="MsoNormal">Bode Plot</p> </td> <td width="307" style="width:230.35pt;border-top:none;border-left:none; border-bottom:solid #009EB8 1.0pt;border-right:solid #009EB8 1.0pt; background:#009EB8;padding:0cm 5.4pt 0cm 5.4pt"> </td> </tr> <tr style="height:184.85pt"> <td width="307" style="width:230.2pt;border:solid #009EB8 1.0pt;border-top: none;padding:0cm 5.4pt 0cm 5.4pt;height:184.85pt"> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image011_en.png"><img border="0" width="292" height="306" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image011_en.png" alt="Technical Document Image Preview" /></a></p> </td> <td width="307" style="width:230.35pt;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:184.85pt"> </td> </tr> </table> <p class="bady">Note: When measuring the input or output voltage ripple, care must be taken to avoid a long ground lead on the oscilloscope probe. Measure the output voltage ripple by touching the probe tip directly across the output capacitor.</p>

11. Evaluation Board Layout

<p class="bady">Figure 1 and Figure 2 are RTQ2531W Evaluation Board layout. This board is constructed on two-layer PCB, outer layers with 1 oz. Cu and inner layers with 1 oz. Cu.</p> <p class="23CxSpFirst"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image012_en.jpg"><img border="0" width="491" height="353" id="圖片 1" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image012_en.jpg" alt="Technical Document Image Preview" /></a></p> <p class="23CxSpMiddle">Figure 1. Top View (1^st layer)</p> <p class="MsoNormal"><a class="fancybox" href="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image013_en.jpg"><img border="0" width="491" height="353" id="圖片 7" src="/content/dam/richtek-eds/resources/evaluation-boards/evb_rtq2531wgqw/html-images/image013_en.jpg" alt="一張含有 文字, 電子用品, 電腦 的圖片 自動產生的描述" /></a></p> <p class="10">Figure 2. Bottom View (2^nd Layer)</p>