6A, 17V, ACOT^® High-Efficiency Synchronous Step-Down Converter Evaluation Board

General Description

This user guide contains information for the RTQ2806A DC-DC converter. Also included are the performance specifications, the schematic, and the list of materials for the RTQ2806A.

Performance Specification Summary

A summary of the RTQ2806A Evaluation Board performance specification is provided in Table 1. The ambient temperature is 25°C.

Table 1. RTQ2806A Evaluation Board Performance Specification Summary

Power-up Procedure

Suggestion Required Equipments

• RTQ2806A Evaluation Board
• DC power supply capable of at least 17V and 7A
• 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 the 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 17V 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
J1	VIN input voltage connector
J2	PGND connection for input
J3	VOUT output voltage connector
J4	PGND connection for output
JP1	Connects EN to VIN to enable the device.
JP2	Connects PGOOD to VCC through a 100kΩ.
JP3	Mode selection
EN	EN test point
SS/REF	Can be used to monitor the reference voltage.
VCC	VCC test point
PGOOD	PGOOD output test point
MODE	Mode selection test point
RLIM	Can be used to monitor the voltage level of the valley current limit.
SW	Switch node 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	Output Ripple Measurement
Load Transient Response	Load Transient Response
Power On from EN	Power Off from EN

Power On from EN	Power Off from EN
Overcurrent Protection	Short-Circuit Protection and Recovery
Overvoltage Protection	Efficiency vs. Output Current

Output Voltage vs. Output Current	Output Voltage vs. Input Voltage
Thermal Image at VIN = 12V, VOUT = 1.8V, IOUT = 6A

Note: Care must be taken to avoid a long ground lead on the oscilloscope probe when measuring the input or output voltage ripple. Measure the output voltage ripple by touching the probe tip directly across the output capacitor.

Evaluation Board Layout

Figures 1 to 4 show the RTQ2806A Evaluation Board layout. This board size is 85mm x 80mm and is constructed on a four-layer PCB, with outer layers of 2 oz. Cu and inner layers with 2 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)