SNOU191 January   2022 LM74502-Q1 , LM74502H-Q1

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Features
    2. 1.2 Applications
  3. 2Description
    1. 2.1 Input Power and Load (J1/J5 and J2/J6, J7/J11 and J8/J12)
    2. 2.2 Two Back-to-Back Connected MOSFETs (Q1/Q2–Q3/Q4 and Q6/Q7–Q8/Q9)
    3. 2.3 Output Slew Rate Control (R1 and C1)
    4. 2.4 Output Schottky Diode (D4, D10) and LED Indication (D6, D12)
    5. 2.5 Test Points
  4. 3Schematic
  5. 4Test Equipment Requirements
    1. 4.1 Power Supplies
    2. 4.2 Meters
    3. 4.3 Oscilloscope
    4. 4.4 Loads
  6. 5Test Setup and Results
    1. 5.1 Initial Setup
    2. 5.2 Power Up
    3. 5.3 Turn-ON with EN
    4. 5.4 Inrush Current Control
    5. 5.5 Overvoltage Response
    6. 5.6 Reverse Polarity Protection
  7. 6Board Layout and Bill of Materials
    1. 6.1 Board Layout
    2. 6.2 Bill of Materials

2.5 Test Points

Table 2-1 lists the LM74502Q1EVM board input and output connector functionality. Table 2-2 and Table 2-3 describe the test points description and the jumper functionality of the EVM respectively.

Table 2-1 Connectors: Input and Output

Channel

ConnectorDescription

1

J1Power input connector to the positive rail of the input power supply
J5Ground connection for the power supply
J2Power output connector to the positive side of the load
J6Ground connection for the load

2

J7

Power input connector to the positive rail of the input power supply

J11

Ground connection for the power supply

J8

Power output connector to the positive side of the load

J12

Ground connection for the load
Table 2-2 Test Points Description

Test Point

NameDescription

TP1

VIN1Input power supply to the EVM - channel 1
TP2VOUT1Output from the EVM - channel 1
TP5

GATE1

Output of controller’s gate pin – channel 1
TP6OV1Adjustable input at the overvoltage pin – channel 1
TP7

VS1

Power supply to the controller – channel 1
TP8

EN/UVLO1

EN/UVLO input to the controller – channel 1

TP9

VIN2

Input power supply to the EVM - channel 2

TP10VOUT2Output from the EVM - channel 2
TP14OV2Adjustable input at the overvoltage pin – channel 2
TP15VS2Power supply to the controller – channel 2
TP16EN/UVLO2EN/UVLO input to the controller – channel 2
TP3,TP4,TP11,TP12

PGND

Test point for EVM ground
Table 2-3 Jumpers and LED Description
JumpersDescription
J4

OV protection setting channel 1

  • 1-2 sets the device in OV cutoff mode

  • 2-3 sets the device in OV clamp mode

J3Enables LED indication for output – channel 1
J10

OV protection setting channel 2

  • 1-2 sets the device in OV cutoff mode

  • 2-3 sets the device in OV clamp mode

J9Enables LED indication for output – channel 2