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RT9746 VBUS OVP with a PTVS Diode

EVB_RT9746WSC

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The RT9746 is an overvoltage protection devices feature a low 35mΩ (typ) RON internal FET with PTVS diode. The PTVS also protects the devices from surges up to 100V. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected down stream components. The internal Over Voltage Thresholds (OVP) are preset to 6.8V typical. The RT9746 also feature an over-current protection and up to 4.5A. The RT9746 is offered in a small WL-CSP-12B (BSC) package provides small PCB area applications.

Purpose

The RT9746 is a VBUS OVP protector switch. This document explains the function and use of the RT9746 evaluation board (EVB), and provides information to enable operation, output voltage setting of the evaluation board.


Introduction

General Product Information

The RT9746 is an over voltage protection devices feature a low 35mΩ (typ) RON internal FET with PTVS diode. The PTVS also protects the devices from surges up to 100V. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected down stream components. The internal Over Voltage Thresholds (OVP) are preset to 6.8V typical. The RT9746 also feature an over-current protection and up to 4.5A. The RT9746 is offered in a small WL-CSP-12B (BSC) package provides small PCB area applications.


Product Feature

  • PTVS Diode Embedded for VBUS Surge Protection
  • Warning Indicator for OVP or UVP
  • 28V Maximum Rating for DC Adapt
  • Integrated Over-Voltage and Over Current Protection FET on VBUS for Fault Isolation


Key Performance Summary Table

Key Features

Evaluation Board Number: PCB083_V1

Default Input Voltage

5V

Max Output Over Current

4.5A

Default Marking & Package Type

RT9746WSC, WL-CSP-12B 1.92x1.27 (BSC)


Bench Test Setup Conditions

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

Signal

Comment (expected waveforms or voltage levels on test points)

VIN

Input voltage

VBUS from Power Adaptor.

OVP OUT

Output voltage

Output from VBUS Load-Switch.

OVPFB

External OVP Adjustment Setting

If no used, be surely tied to GND.

GND

Ground

Ground.

WRNB

Inverse Warning Signal

OCP,OTP, OVP, UVLO Flag Output (Open-Drain)


Power-up

The RT9746 has a threshold of 2.7V power on reset (POR) with a built-in hysteresis of 100mV. Before the input voltage reaches the POR threshold, the RT9746 is off. When the input voltage is over the POR threshold, the VOUT of RT9746 will delay for 32ms which includes soft-start time of 8ms.

Input Over-Voltage Protection

The RT9746 provides input over-voltage protection via internal or external resistor to set OVP level.

  • If OVPFB is connected to GND, the RT9746 uses the internal OVP level setting.
  • If an external resistor-divider is connected to OVPFB and VOVPFB exceeds the VOVP_SEL voltage, the RT9746 will adopt external OVP level setting. The OVP level VOVP is set as below.
    Technical Document Image Preview


Schematic, Bill of Materials & Board Layout


EVB Schematic Diagram

Technical Document Image Preview


Bill of Materials

Reference

Qty

Part number

Description

Package

Manufacturer

U1

1

RT9746WSC

VBUS OVP IC with PTVS Diode

WL-CSP-12B 1.92x1.27(BSC)

RICHTEK

C1

1

C1608X7R1H104K080AA

0.1µF/50V/X7R/0603

C-0603

TDK

C4

1

C2012X7R1E105KT

1µF/25V/X7R/0805

C-0805

TDK

R1

1

0805T-5-0R

0R/0805

R-0805

RALEC


PCB Layout

Technical Document Image Preview

Top View

Technical Document Image Preview

Bottom View

Title Last Update Share Download
Evaluation Board User Guide 2016/12/15
Bill of Materials 2016/12/15
Gerber File 2016/12/15
Schematic 2016/12/15
RT9746

VBUS OVP with a PTVS Diode

RT9746

The RT9746 is an overvoltage protection devices feature a low 35mΩ (typ) RON internal FET with PTVS diode. The PTVS also protects the devices from surges up to 100V. When the input voltage exceeds the overvoltage threshold, the internal FET is turned off to prevent damage to the protected down stream components.

The internal Over Voltage Thresholds (OVP) are preset to 6.8V typical. The RT9746 also feature an over-current protection and up to 4.5A.

The RT9746 is offered in a small WL-CSP-12B (BSC) package provides small PCB area applications.

Part NumberFree SampleBuy From Authorized Distributor
EVB_RT9746WSC Not available Buy from Distributor
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