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RT6321AN-A, 23VIN, 12A Buck Converter Evaluation Board

EVB_RT6321AN-A

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The Evaluation Board demonstrates the RT6321AN-A to be designed for a programmed between 0.6V to 5.5V/12A output from a 4.5V to 23V input at 500kHz switching frequency. The RT6321AN-A 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 RT6321AN-A to be designed for a programmed between 0.6V to 5.5V/12A output from a 4.5V to 23V input at 500kHz switching frequency. The RT6321AN-A 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 RT6321AN-A Evaluation Board performance specificiaiton is provided in Table 1. The ambient temperature is 25°C.


Table 1. RT6321AN-A Evaluation Board Performance Specification Summary

Specification

Test Conditions

Min

Typ

Max

Unit

Input Voltage Range

4.5

--

23

V

Output Current

0

--

12

A

Default Output Voltage

--

1.05

--

V

Operation Frequency

--

500

--

kHz

Output Ripple Voltage

IOUT = 12A

--

22

--

mVp-p

Line Regulation

IOUT = 12A, VIN = 4.5V to 23V

--

±1

--

%

Load Regulation

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

--

±1

--

%

Load Transient Response

VOUT = 1.05V , IOUT = 1.2A to 12A

--

±5

--

%

Maximum Efficiency

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

--

91

--

%



Power-up Procedure

Suggestion Required Equipments

  • RT6321AN-A Evaluation Board
  • DC power supply capable of at least 25V and 6A
  • Electronic load capable of 12A
  • 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, 螢幕擷取畫面, 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/MODE

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.

LPM

Low power mode control input pin.

ILMT

Valley current-limit setting pin.

14A: Connect the ILMT pin to PGND.

16A: Leave the ILMT pin floating/open.

18A: Connect the ILMT pin to 5V.

JP21

ILMT jumper. Connect ILMT to VCC or floating.

LX

Switch node test point.

PG

Power good indicator.

BS

Bootstrap test pin.

JP3

VOUT ripple measure test pin.



Bill of Materials

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

Reference

Count

Part Number

Value

Description

Package

Manufacturer

U1

1

RT6321A

RT6321AN-A

Buck Converter

UQFN-26L 4x3 (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, C24

2

0603B104K500CT

0.1µF

Capacitor, Ceramic, 50V, X7R

0603

WALSN

C21, C22

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

WR06X4122FTL

41.2k

Resistor, Chip, 1/10W, 1%

0603

WALSIN

R4, R6, R9, R38, R40

5

WR06X000 PTL

0

Resistor, Chip, 1/10W, 1%

0603

WALSIN

R8, R25, R27

3

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

Quiescent Current vs. Input Voltage

Technical Document Image Preview

Technical Document Image Preview

Thermal Image at VIN = 19V, VOUT = 1.05V, IOUT = 12A

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 RT6321AN-A Evaluation Board layout. This board size is 89mmx76mm 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, 圖表, 圓形 的圖片

自動產生的描述

Figure 1. Top View (1st layer)


一張含有 螢幕擷取畫面, 文字, Rectangle, 圓形 的圖片

自動產生的描述

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


一張含有 螢幕擷取畫面, 文字, 圓形, Rectangle 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, Rectangle, 圓形 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
RT6321
RT6321

The RT6321 is high efficiency synchronous step-down DC-DC converters with pseudo constant switching frequency 500kHz and deliver up to 12A output current. The RT6321 operates from 4.5V to 23V input voltage. The output voltage of RT6321 is programmed between 0.6V to 5.5V. The RT6321 supports low power mode (LPM) to dynamically change output voltage between target voltage and zero voltage.

The RT6321 adopts Advanced Constant On-Time (ACOT®) control architecture that provides ultra-fast transient response and further reduces the external component count. In steady states, the ACOT® operates at nearly constant switching frequency over line, load and output voltage ranges and makes the EMI filter design easier.

By setting the voltage of the EN/MODE pin, RT6321 operates either in diode emulation mode (DEM) or ultrasonic mode (USM) at light load. The USM maintains operation frequency above 25kHz, which eliminates the acoustic noise. In the DEM, RT6321 provides the best light-load efficiency and improves the acoustic noise with spread spectrum function.

RT6321 provides PGOOD indicator for easy system sequence control. Full protection features are also integrated in the device, including the cycle-by-cycle current limit, OVP, UVP, input UVLO and OTP.

All above functions are integrated in a UQFN-26L 4x3 (FC) package.

Part NumberDistributorStockBuy From Authorized Distributor
EVB_RT6321AN-A Digikey 5 Buy
Mouser 0 Lead-Time: 14 weeks
IC
Part NumberPackage TypePackage Qty.Free SampleDistributorStockBuy From Authorized Distributor
RT6321AN-AUQFN4x3-26(FC)1,500 Request Digikey 1,500 Buy
Mouser 0 Lead-Time: 14 weeks
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