RTQ6340GQW, 42V_IN, 0.5A, Asynchronous Step-Down Converter Evaluation Board

General Description

The Evaluation Board demonstrates the RTQ6340GQW to be designed for a 5V/0.5A output from a 8V to 42V input at 500kHz switching frequency. The wide input range makes it suitable for communications and industrial 12V, 24V and 36V power systems. The RTQ6340GQW 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 Sepcification Summary

Summary of the RTQ6340GQW Evaluation Board performance specificiaiton is provided in Table 1. The ambient temperature is 25°C.

Table 1. RTQ6340GQW Evaluation Board Performance Specification Summary

Power-up Procedure

Suggestion Required Equipments

• RTQ6340GQW Evaluation Board
• DC power supply capable of at least 42V and 1A
• Electronic load capable of 6A
• 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 42V 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

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 test point.
J3	EN jumper. Connect EN to ground to disable, open to enable.
SW	Switch node test point.
V2	Test pin V2 is used for bode plot measurement. Connect VOUT pin and this pin to the injection transformer.
SS/TR	Soft-start and tracking test point.
VPG_Ext	Test point for pull up voltage of the Open-drain power-good indication output.
PGOOD	Power-good indication test point.

Bill of Materials

Typical Applications

EVB Schematic Diagram

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

Output Ripple Measurement	Load Transient Response
Power On from EN	Power Off from EN
Short Circuit Response – Short and Recovery	Start-Up Dropout Performance

Efficiency vs. Output Current	Output Voltage vs. Output Current
Output Voltage vs. Input Voltage	Loop Response
Thermal Image at VIN = 12V, VOUT = 5V, IOUT = 0.5A

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 RTQ6340GQW Evaluation Board layout. This board size is 70mm x 50mm and is constructed on four-layer PCB, outer layers with 2 oz. Cu and inner layers with 1 oz. Cu.

Figure 1. Top View (1^st layer)

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

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

Figure 4. Bottom View (4^th Layer)