36V, 0.7A, Synchronous Step-Down Converter Evaluation Board

General Description

The Evaluation Board demonstrates the RTQ2130B-50 to be designed for a 5V/0.7A output from a 7V to 25V input at 2.1MHz switching frequency. The wide input range makes it suitable for automotive systems and car camera module. The RTQ2130B-50 provides complete protection functions such as input undervoltage lockout, output undervoltage protection, overcurrent protection, and thermal shutdown. 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 RTQ2130B-50 Evaluation Board performance specificiaiton is provided in Table 1. The ambient temperature is 25^oC.

Table 1. RTQ2130B-50 Evaluation Board Performance Specification Summary

Power-up Procedure

Suggestion Required Equipment

• RTQ2130B Evaluation Board
• DC power supply capable of at least 36V and 1A
• Electronic load capable of 6A
• Function Generator
• Oscilloscope

Quick Start Procedure

The Evaluation Board is fully assembled and tested. Follow the steps below to verify board operation. Caution: Do not turn on supplies until all connections are made. Note: 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 36V 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.

Enable

For automatic start-upn, the EN pin, with high-voltage rating, can be connected to the input voltage by a 100kΩ through the JP1. Shutdown the converter by short EN pin to GND through the JP1.

Test Points

The EVB is provided with the test points and pin names listed in the table below.

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

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 RTQ2130B Evaluation Board layout. This board size is 110mmx80mm and is constructed on four-layer PCB with 1 OZ. Cu on the outer layers and 1 OZ. Cu in the inner layers.

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)