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2A Ultra-Low Dropout Voltage LDO Regulators with Soft-Start Evalution Board Guidance

EVB_RTQ2522AGQW(2)

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The Evaluation Board user guide describes the operational use of the RTQ2522A evaluation board as a reference design for demonstration and evaluation of the RTQ2522A, an ultra-low dropout (LDO) linear regulator with soft-start.

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 RTQ2522A datasheet.

General Description

The Evaluation Board user guide describes the operational use of the RTQ2522A evaluation board as a reference design for demonstration and evaluation of the RTQ2522A, an ultra-low dropout (LDO) linear regulator with soft-start.

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 RTQ2522A datasheet



Performance Specification Summary

Summary of the RTQ2522A Evaluation Board performance specificiaiton is provided in Table 1. The ambient temperature is 25°C.


Table 1. RTQ2522A Evaluation Board Performance Specification Summary

Specification

Test Conditions

Min

Typ

Max

Unit

Input Voltage Range

VOUT + Vdrop

1.1

5.5

V

VBIAS Pin Voltage

2.7

--

5.5

V

Output Voltage Range

Vin = 5V, IOUT = 2A

0.8

0.8

3.6

V

Line Regulation

VOUT (normal) + 0.3V ≤ VIN ≤ 5.5V

--

0.03

--

%/V

Load Regulation

50mA ≤ IOUT ≤ 2A

--

0.09

--

%/A

VIN Dropout Voltage

IOUT = 2A,

VBIAS – VOUT (normal) ≥ 3.25V

--

100

150

mV

VBIAS Dropout Voltage

VOUT = 80% x VOUT (normal)

--

1.55

1.8

V

Power-up Procedure

Suggestion Required Equipments

  • RTQ2522A Evaluation Board
  • DC power supply capable of at least 5.5V and 2A
  • Electronic load capable of 2A
  • Function Generator
  • Oscilloscope

Quick Start Procedures

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.


Proper measurement equipment setup and follow the procedure below.

1) With power off, connect the input power supply to VIN and GND pins.

2) With power off, connect the electronic load between the VOUT and nearest GND pins.

3) Turn on the power supply at the input. Make sure that the input voltage does not exceeds 6V on the Evaluation Board.

4) Check for the proper output voltage using a voltmeter.

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.



Detailed Description of Hardware

Headers Description and Placement

Technical Document Image Preview

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.


Test Points

The EVB is provided with the test points and pin names listed in the table below.

Test Point/

Pin Name

Function

VIN

Supply input pin.

VOUT

Output of the regulator.

PG

Power good sense pin.

VBIAS

Input pin of bias voltage.

EN

Enable sense pin.

GND

System ground pin.

SS

Soft-start capacitor waveform sense pin.

ENABLE

User can decide EN pin connected to high or low.

BIAS-EN/VIN-EN

Decision of EN pin pull-high voltage source.

BIAS-PG/VOUT-PG

Decision of PG pull-high voltage source.



Bill of Materials

VIN = 1.1V to 6.5V, VOUT = 0.8V to 5.5V, IOUT = 2A

Reference

Count

Part Number

Value

Description

Package

Manufacturer

U1

1

RTQ2522AGQW(2)

RTQ2522A

LDO

WDFN-10L 3x3

RICHTEK

C1

1

TMK212BJ475KG-T

4.7μF

Capacitor, ceramic,

25V, X5R

0805

TAIYO YUDEN

C3

1

GRM21BR71A106KE51L

10μF

Capacitor, ceramic,

10V, X7R

0805

MURATA

CBIAS

1

0805B105K250CT

1μF

Capacitor, ceramic,

25V, X7R

0805

WALSIN

CSS

1

0603B102K500CT

1nF

Capacitor, ceramic,

50V, X7R

0603

WALSIN

R1, R5

2

WR06X000 PTL

0

Resistor, chip

0603

WALSIN

REN1, REN2, RPG1, RPG2

4

WR06X1003FTL

100k

Resistor, chip

0603

WALSIN



Typical Applications

EVB Schematic Diagram

Technical Document Image Preview

1. The capacitance values of the input and output capacitors will influence the input and output voltage ripple.

2. MLCC capacitors have degrading capacitance at DC bias voltage, and especially smaller size MLCC capacitors will have much lower capacitance.


Measure Result

Power Up Response

Enable Voltage Threshold vs. Temperature

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Technical Document Image Preview

VBIAS Voltage UVLO vs. Temperature

Dropout Voltage vs. Output Current

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Output Spectral Noise Density

VIN PSRR vs. Frequency

Technical Document Image Preview

Technical Document Image Preview

Load Transient Response

OCP

Technical Document Image Preview

Technical Document Image Preview

Short Protection

Bode Plot

Technical Document Image Preview

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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.



Evaluation Board Layout

Figure 1 to Figure 4 are RTQ2522A Evaluation Board layout. This board is constructed on four-layer PCB, outer layers with 1 oz. Cu and inner layers with 1 oz. Cu.

一張含有 文字, 電子用品 的圖片

自動產生的描述

Figure 1. Top View (1st layer)


Technical Document Image Preview

Figure 2. PCB Layout—Inner Side (2nd Layer)


Technical Document Image Preview

Figure 3. PCB Layout—Inner Side (3rd Layer)


一張含有 文字, 電子用品 的圖片

自動產生的描述

Figure 4. Bottom View (4th Layer)

Title Last Update Share Download
Evaluation Board User Guide 2023/03/17
Bill of Materials 2023/03/17
Schematic 2023/03/17
Gerber File 2023/03/17
RTQ2522A/RTQ2522B
RTQ2522A/RTQ2522B

RTQ2522A/B 是最低输入电压可达 0.8V 的极低压差线性稳压器,可以典型直通压差 90mV 提供 2A 的负载能力,它在工作时需要一个 VBIAS 电源输入以驱动其内部参考电源和调节电路工作,而其输出电流则来源于 VIN 以实现高效率的电压转换。通过使用用户可调的软启动设计,其对输入电流的冲击受到限制,电源输入端的供电压力得以变小。它还拥有使能输入和 Power Good 输出,方便进行电源系统的时序设计。这些特性为设计提供了灵活性,可以为多变的应用环境带来方便,容易得到好用耐用的系统。
RTQ2522A/B 配合 2.2μF 以上的输出电容即可稳定工作,精确的参考电源和误差放大器为其带来超过 2% 的输出精度,基本不受输入、输出和环境温度的影响。它还具有过流限制和过热保护功能,其封装形式包括 WDFN-10L 3x3 和 WQFN-20L 5x5。

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