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6V Input, 1A, ACOT® Buck Converter in Thin SOT-563 (FC)

EVB_RT5760AHGH6F

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The RT5760A is a full featured 6V, 1A, Advanced Constant-On-Time (ACOT®) synchronous step-down converter with two integrated MOSFETs. This document explains the function and use of the RT5760A evaluation board (EVB) and provides information for the evaluation board layout, schematic, bill of materials (BOM) and measurement results to suit individual requirements.

General Description

The RT5760A is a full featured 6V, 1A, Advanced Constant-On-Time (ACOT®) synchronous step-down converter with two integrated MOSFETs. This document explains the function and use of the RT5760A evaluation board (EVB) and provides information for the evaluation board layout, schematic, bill of materials (BOM) and measurement results to suit individual requirements.



Performance Specification Summary

Summary of the RT5760AHGH6F Evaluation Board performance specificiaiton is provided in Table 1. The ambient temperature is 25°C.


Table 1. RT5760AHGH6F Evaluation Board Performance Specification Summary

Specification

Test Conditions

Min

Typ

Max

Unit

Input Voltage Range

2.5

--

6

V

Output Current

0

--

1

A

Default Output Voltage

--

1

--

V

Operation Frequency

--

2.2

--

MHz

Output Ripple Voltage

IOUT = 1A

--

10

--

mVp-p

Line Regulation

IOUT = 1A, VIN = 2.5V to 6V

--

±1

--

%

Load Regulation

VIN = 5V, IOUT = 0.001A to 1A

--

±1

--

%

Load Transient Response

IOUT = 0A to 1A

--

±5

--

%

Efficiency

VIN = 5V, VOUT = 1V, IOUT = 0.4A

--

85.8

--

%



Power-up Procedure

Suggestion Required Equipments

  • RT5760AHGH6F Evaluation Board
  • DC power supply capable of at least 6V and 1A
  • Electronic load capable of 1A
  • 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 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 60V 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

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

Signal

Comment (expected waveforms or voltage levels on test points)

VIN

Input Voltage

Positive input voltage from the power supply to the EVB.

VOUT

Output Voltage

Positive output voltage from the EVB to the loads.

JP1

Output Voltage Test Point

Output voltage measurement point.

GND

Ground

Reference voltage for input voltage, output voltage and other test points.

LX

Switch Node Test Point

Frequency measurement point. 2.2MHz (Typ.) in CCM mode.

PG

Power Good Test Point

Power good indicator. Pull low for fault condition.

EN

Enable Test Point

Enable control input. Connect this pin to logic high to enable the device.

JP2

EN Pin Jumper

Place the jumper across on EN and H to enable the device. Place the jumper across on EN and L to disable the device.


Power-up & Measurement Procedure

1. Connect a input power supply to the VIN and GND terminals and an electrical load to the VOUT and GND terminals.

2. Set the jumper at JP2 to tie “EN” test pin to “H” pin for enabling the chip.

3. Apply a 5V nominal input power supply (2.5V < VIN < 6V) to the VIN and GND terminals respectively.

4. Set the electrical load up to 1A to Verify the output voltage (approximately 1V) at JP1. Check LX frequency is around 2.2MHz in CCM mode.


Output Voltage Setting

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 :

Technical Document Image Preview

The placement of the resistive divider should be within 5mm of the FB pin. The resistance of R2 is suggested to 10kΩ for noise pick-up at the FB pin. The resistance of R1 can then be obtained as below :

Technical Document Image Preview

For better output voltage accuracy, divider resistors (R1 and R2) should have tolerance of ±1% tolerance or better.



Bill of Materials

Reference

Qty

Part Number

Description

Package

Manufacturer

U1

1

RT5760AHGH6F

Step-Down

DC-DC Converter

SOT-563

WALSIN

C1, C4, C5

3

NC

C-0603

C2, C6

2

0603X106M6R3CT

10µF/6.3V/X5R/0603

C-0603

WALSIN

C3

1

C1005X7R1C104K050BC

100nF/16V/X7R/0402

C-0402

TDK

C7

1

C1608X7R1H104K080AA

100nF/50V/X7R/0603

C-0603

TDK

L1

1

DFE252010F-1R0M

1µH

L-2520

Murata

R1

1

WR06X6651FTL

6.65K/0603

R-0603

WALSIN

R2

1

WR06X1002FTL

10K/0603

R-0603

WALSIN

R3, R4

2

WR06X1003FTL

100K/0603

R-0603

WALSIN

R5

1

NC

R-0603

R6

1

WR06X000 PTL

0/0603

R-0603

WALSIN



Typical Applications

EVB Schematic Diagram

Technical Document Image Preview

Note:

1. Do not hot-plug a live 5V supply to the board. If hot-plugging is required, add ~ 100µF electrolytic capacitor at the input.


Measurement Results

Power-On from VIN

Yellow: VOUT; Cyan: LX; Pink: VIN; Green: PG

Power-Off from VIN

Yellow: VOUT; Cyan: LX; Pink: VIN Green: PG

Technical Document Image Preview

Technical Document Image Preview

VIN = 5V, VOUT = 1V, IOUT = 1A

VIN = 5V, VOUT = 1V, IOUT = 1A

Power-On from EN

Yellow: VOUT; Cyan: LX; Pink: EN; Green: PG

Power-Off from EN

Yellow: VOUT; Cyan: LX; Pink: EN; Green: PG

Technical Document Image Preview

Technical Document Image Preview

VIN = 5V, VOUT = 1V, IOUT = 1A

VIN = 5V, VOUT = 1V, IOUT = 1A

Output Ripple Measurement

Yellow: VOUT; Cyan: LX

Output Ripple Measurement

Yellow: VOUT; Cyan: LX

Technical Document Image Preview

Technical Document Image Preview

VIN = 5V, VOUT = 1V, IOUT = 0.01A

Output ripple: 17.6mVpp (PSM)

VIN = 5V, VOUT = 1V, IOUT = 1A

Output ripple: 4mVpp, Frequency: 2.164MHz (CCM)

Fast Dynamic Load

Yellow: VOUT; Cyan: LX; Pink: IOUT

Fast Dynamic Load

Yellow: VOUT; Cyan: LX; Pink: IOUT

Technical Document Image Preview

Technical Document Image Preview

VIN = 5V, VOUT = 1V, IOUT = 0.01A to 0.5A (SR = 1A/µs)

Output ripple: 45.6mVpp

VIN = 5V, VOUT = 1V, IOUT = 0.5A to 1A (SR = 1A/µs)

Output ripple: 52.8mVpp

OCP Function

Yellow: VOUT; Cyan: LX; Green: Inductor current

UVP Function

Yellow: VOUT; Cyan: LX; Green: Inductor current

Technical Document Image Preview

Technical Document Image Preview

VIN = 5V, VOUT = 1V, IOUT = 0A to OCP (Gradually increase load)

Low-side current limit is 1.581A

High-side current limit is 2.711A

VIN = 5V, VOUT = 1V, IOUT = 0A (Output short and recovery)

Bode Plot

Technical Document Image Preview

VIN = 5V, VOUT = 1V, IOUT = 1A

Bandwidth = 402kHz

Phase Margin = 56.4


Efficiency Measurements

Technical Document Image Preview



Evaluation Board Layout

Technical Document Image Preview

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)


Technical Document Image Preview

Figure 4. Bottom View (4th Layer)

Title Last Update Share Download
Evaluation Board User Guide 2023/02/09
Bill of Materials 2023/02/09
Schematic 2023/02/09
Gerber File 2023/02/09
RT5760A/RT5760B/RT5760C/RT5760D
RT5760A/RT5760B/RT5760C/RT5760D

The RT5760A/B/C/D is a simple, easy-to-use, 1A synchronous step-down DC-DC converter with an input supply voltage range from 2.5V to 6V. The device build-in an accurate 0.6V reference voltage and integrates low RDS(ON) power MOSFETs to achieve high efficiency in a SOT-563 (FC) package.

The RT5760A/B/C/D adopts Advanced Constant On-Time (ACOT®) control architecture to provide an ultrafast transient response with few external components and to operate in nearly constant switching frequency over the line, load, and output voltage range. The RT5760A/C operate in automatic PSM that maintain high efficiency during light load operation. The RT5760B/D operate in Forced PWM that help to meet tight voltage regulation accuracy requirements.

The RT5760A/B/C/D senses both FETs current for a robust over-current protection. The device features cycle-by-cycle current limit protection and prevent the device from the catastrophic damage in output short circuit, over current or inductor saturation. A built-in soft-start function prevents inrush current during start-up. The device also includes input under-voltage lockout, output under-voltage protection, and over-temperature protection to provide safe and smooth operation in all operating conditions.

Part NumberDistributorStockBuy From Authorized Distributor
EVB_RT5760AHGH6F Digikey 5 Buy
Mouser 0 Lead-Time: 14 weeks
IC
Part NumberPackage TypePackage Qty.Free SampleDistributorStockBuy From Authorized Distributor
RT5760AHGH6FSOT-563(FC)5,000 Request Digikey 4,655 Buy
Mouser 0 Lead-Time: 14 weeks
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