General Description
The Evaluation Board demonstrates that the RT5753AH is designed for a 1.2V/3A output from a 2.5V to 6V input at a 1.2MHz switching frequency. This user’s guide includes setup instructions for the hardware, a printed circuit board (PCB) layout for the EVB, a schematic diagram, a bill of materials, and test results for the EVB.
Performance Specification Summary
A summary of the RT5753AH Evaluation Board performance specification is provided in Table 1. The ambient temperature is 25°C.
Table 1. RT5753AH Evaluation Board Performance Specification Summary
|
Specification
|
Test Conditions
|
Min
|
Typ
|
Max
|
Unit
|
|
Input Voltage Range
|
|
2.5
|
--
|
6
|
V
|
|
Output Current
|
|
0
|
--
|
3
|
A
|
|
Default Output Voltage
|
|
--
|
1.2
|
--
|
V
|
|
Operation Frequency
|
|
--
|
1.2
|
--
|
MHz
|
|
Output Ripple Voltage
|
IOUT = 1.5A
|
--
|
5
|
--
|
mVp-p
|
|
Line Regulation
|
IOUT = 1.5A, VIN = 2.5V to 6V
|
--
|
±1
|
--
|
%
|
|
Load Regulation
|
VIN = 3.6V, IOUT = 0A to 3A
|
--
|
±1
|
--
|
%
|
|
Load Transient Response
|
IOUT = 1.5A to 3A
|
--
|
±5
|
--
|
%
|
|
Peak Efficiency
|
VIN = 3.6V, VOUT = 1.2V
|
--
|
89.2
|
--
|
%
|
Power-up Procedure
Suggestion Required Equipments
- RT5753AH Evaluation Board
- DC power supply capable of at least 6V and 3A
- Electronic load capable of 5A
- 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 6V 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.
|
|
JP1
|
EN jumper. Connect EN to the ground to disable and EN to VIN to enable.
|
|
LX
|
Switch node test point.
|
|
JP2
|
Measure the VOUT waveform and output regulation.
|
|
PGOOD
|
Power-good indication test point.
|
Bill of Materials
|
Reference
|
Count
|
Part Number
|
Value
|
Description
|
Package
|
Manufacturer
|
|
U1
|
1
|
RT5753AHGQW
|
RT5753AH
|
Step-Down Converter
|
WDFN-10SL 3x3
|
RICHTEK
|
|
C2, C3, C4
|
3
|
GRM188R60J226MEA0
|
22µF
|
Capacitor, Ceramic, 6.3V, X5R
|
0603
|
MURATA
|
|
C1
|
1
|
0603N220J500CT
|
22pF
|
Capacitor, Ceramic, 50V, X7R
|
0603
|
WALSIN
|
|
C6, C7
|
2
|
0603B104K500CT
|
0.1µF
|
Capacitor, Ceramic, 16V, X7R
|
0603
|
WALSIN
|
|
L1
|
1
|
DFE322512F-1R0M
|
1µH
|
Inductor, Isat = 4.8A, 32mΩ
|
3.2x 2.5x1.2mm
|
MURATA
|
|
R1, R2, R3, R4
|
4
|
WR06X1003FTL
|
100k
|
Resistor, Chip, 1/10W, 1%
|
0603
|
WALSIN
|
|
R5
|
1
|
WR06X000 PTL
|
0
|
Resistor, Chip, 1/10W, 5%
|
0603
|
WALSIN
|
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
|
|
|
|
|
Power On from EN
|
Power Off from EN
|
|
|
|
|
Load Transient Response
|
Load Transient Response
|
|
|
|
|
Short Circuit Response – Short and Recovery
|
Efficiency vs. Output Current
|
|
|
|
|
Output Voltage vs. Output Current
|
Output Voltage vs. Input Voltage
|
|
|
|
|
Loop Response
|
Thermal Image at
VIN = 3.6V, VOUT = 1.2V, IOUT = 3A
|
|
|
|
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 RT5753AH 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 (1st layer)
Figure 2. PCB Layout—Inner Side (2nd Layer)
Figure 3. PCB Layout—Inner Side (3rd Layer)
Figure 4. Bottom View (4th Layer)