AP6508-EVM

AP6508-EVM
•
500kHz 21V 3A Synchronous DCDC Buck Converter
Description
The AP6508 is a 500kHz switching
frequency
internal
compensated
synchronous DC/DC buck converter. It has
integrated compensation, and low RDSON
high- and low-side MOSFETs.
The AP6508 features current-mode control
operation, which enables fast transient
response times and easy loop stabilization.
• Gaming Consoles
• TV sets and Monitors
• Set Top Boxes
Performance Spec of AP6508FEG-EVM
Parameter
Input voltage
Output Current
Output Voltage
Output Voltage Ripple
Transient Response
The AP6508 has external programmable
Softstart and a Power Good indicator.
The AP6508 is available in a standard
Green DFN4030-14 with exposed pad for
improved thermal performance and is RoHS
compliant.
• Distributed power systems
• Home Audio
• Consumer electronics
Conditions
Range 4.75V to 21V
Peak Deviation
Load step 1.5 A/µs to 3A/µs
Switching Frequency
Efficiency
Figure 1. Evaluation Board
AP6508
Document number: Rev. 1 - 0
Performance Value
12V
3A
1.2V
20mVp-p
70mV
500kHz
90%
Figure 2. Efficiency vs Load Current
1
www.diodes.com
October 2011
© Diodes Incorporated
AP6508-EVM
•
500kHz 21V 3A Synchronous DCDC Buck Converter
Quick Start Guide
The AP6508FEG-EVM has a simple layout and allows access to the appropriate signals through
test points. To evaluate the performance of the AP6508, follow the procedure below:
1. Connect a power supply to the input terminals Vin and GND. Set Vin to 12V.
2. Connect the positive terminal of the electronic load to Vout and negative terminal to
GND.
3. AP6508 will automatically power up through the resistor dividor that connects EN to Vin.
This is only valid when Vin =6.5V to 21V.
4. For Vin =4.5V to 6.5V, Connect a power supply to EN and GND. Set EN=3V.
*DO NOT increase the voltage to EN > 5V, as it will damage the part.
a. To use the EN function drive EN above 1.3V to start the converter and below
0.4V to stop the converter.
5. The evaluation board will power up with a 1.2V output voltage.
6. Check for the proper output voltage of 1.2V(+/-1%) at the output terminals Vout and
GND. Measurement can also be done with a multimeter with the positive and negative
leads between Vout and GND.
7. Set the load to 1.5A through the electronic load. Check for the stable operation of the
SW signal on the oscilloscope. Measure the switching frequency. A test point is
conveniently located at the head of the inductor.
Measurement/Performance Guidelines
1) The evaluation board has the inductor pad spaced for easy access to measure the
inductor current. As shown in the picture, a current probe can be connected to the wire
loop to measure the inductor current.
2) When measuring the output voltage ripple, avoid long ground leads on the oscilloscope
probe.
3) For efficiency measurements, connect an ammeter in series with the input supply to
measure the input current. Connect an electronic load to the output for output current.
AP6508
Document number: Rev. 1 - 0
2
www.diodes.com
October 2011
© Diodes Incorporated
AP6508-EVM
•
500kHz 21V 3A Synchronous DCDC Buck Converter
EVALUATION BOARD SCHEMATIC
BILL OF MATERIALS
QTY
REF
VALUE
DESCRIPTION
PACKAGE
MANUFACTURER
1
C1
22uF
1210
AVX
2
C2
47uF
1210
AVX
3
0.1uF
0603
TDK
GRM32ER61A476K
E20L
C1608X7R1H104M
4
C3,
C4
C5
47nF
Ceramic Capacitor,
25V,X5R
Ceramic Capacitor,
10V, X5R
Ceramic Capacitor,
50V, X7R
Ceramic Capacitor,
16V, X7R
0603
TDK
C1608X7R1C473M
5
C6
DNP
6
L1
3.3uH
Inductor, 5.3A
SMD
Wurth Electronics
7440650033
7
R1
4.99k
Resistor, 1%
0603
Panasonic
ERJ-3EKF4991V
8
R2
10.2k
Resistor, 1%
0603
Panasonic
ERJ-3EKF1022V
9
R3,
R5
R4,
R6
U1
24.9k
Resistor, 1%
0603
Panasonic
ERJ-3EKF2492V
100k
Resistor, 1%
0603
Panasonic
ERJ-3EKF1003V
DC/DC Converter
DFN403014
Diodes Inc
AP6508
10
11
AP6508
Document number: Rev. 1 - 0
3
www.diodes.com
MANUFACTURER
P/N
12103D226KAT2A
October 2011
© Diodes Incorporated
AP6508-EVM
•
500kHz 21V 3A Synchronous DCDC Buck Converter
TOP SILK LAYER
TOP LAYER
BOTTOM LAYER
AP6508
Document number: Rev. 1 - 0
4
www.diodes.com
October 2011
© Diodes Incorporated
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