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RT6338AGQUF, 23VIN, 8A Buck Converter Evaluation Board

EVB_RT6338AGQUF

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The Evaluation Board demonstrates the RT6338AGQUF to be designed for a programmed between 0.6V to 5.5V/8A output from a 4.5V to 23V input at 500kHz switching frequency. The RT6338AGQUF provides complete protection functions such as input undervoltage-lockout, output undervoltage protection, overcurrent protection and thermal shut down. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates input current surge during start-up.

General Description

The Evaluation Board demonstrates the RT6338AGQUF to be designed for a programmed between 0.6V to 5.5V/8A output from a 4.5V to 23V input at 500kHz switching frequency. The RT6338AGQUF provides complete protection functions such as input undervoltage-lockout, output undervoltage protection, overcurrent protection and thermal shut down. Cycle-by-cycle current limit provides protection against shorted outputs and soft-start eliminates input current surge during start-up.



Performance Specification Summary

Summary of the RT6338AGQUF Evaluation Board performance specificiaiton is provided in Table 1. The ambient temperature is 25°C.


Table 1. RT6338AGQUF Evaluation Board Performance Specification Summary

Specification

Test Conditions

Min

Typ

Max

Unit

Input Voltage Range

4.5

--

23

V

Output Current

0

--

8

A

Default Output Voltage

--

1.05

--

V

Operation Frequency

--

500

--

kHz

Output Ripple Voltage

IOUT = 8A

--

11

--

mVp-p

Line Regulation

IOUT = 8A, VIN = 4.5V to 23V

--

±1

--

%

Load Regulation

VIN = 12V, IOUT = 0.001A to 8A

--

±1

--

%

Load Transient Response

VOUT = 1.05V , IOUT = 0.8A to 8A

--

±5

--

%

Maximum Efficiency

VIN = 12V, VOUT = 1.05V, IOUT = 2A, VCC_EXT = 5V

--

91

--

%



Power-up Procedure

Suggestion Required Equipments

  • RT6338AGQUF Evaluation Board
  • DC power supply capable of at least 25V and 6A
  • Electronic load capable of 8A
  • 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 ground ring 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 the 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 23V 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, ripple voltage, efficiency and other performance.



Detailed Description of Hardware

Headers Description and Placement

一張含有 文字, 電子產品, 電路, 電子工程 的圖片

自動產生的描述

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

Input voltage.

VOUT

Output voltage.

GND

Ground.

EN

Enable and operation mode control input.

VCC_EXT

External voltage input for VCC.

VCC

Internal LDO output. Used as supply to internal control circuits. DO NOT connect to any external loads.

ILMT

Valley current-limit setting pin.

10A: Connect the ILMT pin to PGND.

12A: Leave the ILMT pin floating/open.

14A: Connect the ILMT pin to 5V.

JP11

ILMT jumper. Connect ILMT to VCC,GND or floating.

LX

Switch node test point.

PG

Power good indicator.

BS

Bootstrap test pin.

JP3

VOUT ripple measurement test pin.



Bill of Materials

VIN = 12V, VOUT = 1.05V, IOUT = 8A, fSW = 500kHz

Reference

Count

Part Number

Value

Description

Package

Manufacturer

U1

1

RT6338A

RT6338AGQUF

Buck Converter

UQFN-23L 3x3 (FC)

RICHTEK

C3

1

0603N680J500CT

68pF

Capacitor, Ceramic, 50V, NPO

0603

WALSN

C4, C5, C6, C7, C8, C9

6

0805X226M6R3CT

22µF

Capacitor, Ceramic, 6.3V, X5R

0805

WALSN

C18, C41

2

0603B104K500CT

0.1µF

Capacitor, Ceramic, 50V, X7R

0603

WALSN

C22, C23

2

0805X106K250CT

10µF

Capacitor, Ceramic, 25V, X5R

0805

WALSN

C28

1

0603X475K6R3CT

4.7µF

Capacitor, Ceramic, 6.3V, X5R

0603

WALSN

C40

1

0603X475K6R3CT

4.7µF

Capacitor, Ceramic, 6.3V, X5R

0603

WALSN

L1

1

PEUE063T-R68MS

0.68µH

Inductor, Isat = 18.5A, 4.3mΩ

7.3x6.8x3mm

CYNTEC

R1

1

RTT033092FTP

30.9k

Resistor, Chip, 1/10W, 1%

0603

RALEC

R2

1

RMC16K4122FTP

41.2k

Resistor, Chip, 1/10W, 1%

0603

KAMAYA

R4, R6, R9, R10, R11

5

WR06X000 PTL

0

Resistor, Chip, 1/10W, 1%

0603

WALSIN

R8

1

WR06X1003FTL

100k

Resistor, Chip, 1/10W, 1%

0603

WALSIN

R17

1

WR06W1R10FTL

1.1

Resistor, Chip, 1/10W, 1%

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

Load Transient Response

Power On from EN/MODE

Technical Document Image Preview

Technical Document Image Preview

Power Off from EN

Overcurrent Limit

Technical Document Image Preview

Technical Document Image Preview

VOUT UVP

VOUT OVP

Technical Document Image Preview

Technical Document Image Preview

Efficiency vs. Output Current

Switching Frequency vs. Output Current

Technical Document Image Preview

Technical Document Image Preview

Output Voltage vs. Output Current

Loop Response

Technical Document Image Preview

Technical Document Image Preview

Thermal Image at VIN = 19V, VOUT = 1.05V, IOUT = 8A

Technical Document Image Preview


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 RT6338AGQUF Evaluation Board layout. This board size is 90mm x 70mm and is constructed on four-layer PCB, outer layers with 2 oz. Cu and inner layers with 1 oz. Cu.

一張含有 文字, 螢幕擷取畫面, 圓形, 圖表 的圖片

自動產生的描述

Figure 1. Top View (1st layer)


一張含有 文字, 螢幕擷取畫面, 圓形 的圖片

自動產生的描述

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


一張含有 文字, 螢幕擷取畫面, 圓形, 設計 的圖片

自動產生的描述

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


一張含有 文字, 螢幕擷取畫面, 圓形, 圖表 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 2024/10/21
Bill of Materials 2024/10/21
Schematic 2024/10/21
Gerber File 2024/10/21
RT6338
RT6338

RT6338 系列產品是負載能力達8A、工作頻率穩定在500kHz 的高效同步Buck 轉換器,RT638A/B和RT6338AH/BH的輸入電壓範圍為4.5V~23V,RT6338A/AH的輸出電壓範圍為0.6V~5.5 V, RT6338B/BH 的輸出電壓為固定的3.3V。 RT6338C/CH 的輸入電壓範圍為 5.2V-23V、輸出電壓為固定的 5.1V。
RT6338 採用ACOT® 改進型固定導通時間控制架構,具有極快的瞬態響應速度,外圍元件數量大幅減少,穩態工作時的工作頻率幾乎保持恆定,不受輸入電壓、負載電流及輸出電壓的影響,使電磁兼容濾波器的設計變得容易許多。
通過對 EN/MODE 引腳電壓的控制,RT6338 可選擇工作於二極管仿真模式或超聲模式以解決輕載效率下降問題。超聲模式的工作頻率高於 25kHz,因而不會帶來可聽見的音頻噪聲。二極管仿真模式可使輕載效率最佳化,同時還以頻譜擴展方式降低音頻噪聲的影響。
為了方便進行時序控制,RT6338 提供了 Power Good 輸出。它還具有逐週期電流限制保護、過壓保護、欠壓保護、輸入欠壓鎖定保護和過熱保護等功能,其封裝形式為 UQFN-23L 3x3 (FC)。

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