AN4189
Application note
Sound Terminal
®
2.0-channel microless high-efficiency digital
audio system demonstration board based on the STA335ML
Introduction
The STEVAL-CCA049V1 is a demonstration board designed for the evaluation of the
STA335ML Sound Terminal
®
high-efficiency digital amplifier. The purpose of this application
note is to show how to connect the 2.0-channel demonstration board and to explain how to
avoid critical board and layout issues.
The STEVAL-CCA049V1 demonstration board is configured for 2.0 BTL channels, releasing
up to 2 x 20 W into 8
Ω
of power output at 18 V supply voltage in the PSSO36 slug-down
package. It represents a complete solution for a digital audio power amplifier capable of
operating without the aid of an external microcontroller.
Figure 1.
STEVAL-CCA049V1
November 2012
Doc ID 023809 Rev 1
1/23
www.st.com
Contents
AN4189
Contents
1
Test conditions and connections of demonstration board . . . . . . . . . . 3
1.1
Test conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1
1.1.2
Jumpers, power supply, signal and interface settings . . . . . . . . . . . . . . . 3
Output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2
3
Schematic and bill of material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Design guidelines for PCB schematic and layout . . . . . . . . . . . . . . . . . 9
3.1
Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1.1
3.1.2
3.1.3
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Decoupling capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Output filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2
Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
2/23
Doc ID 023809 Rev 1
AN4189
Test conditions and connections of demonstration board
1
Test conditions and connections of demonstration
board
Test conditions
Jumpers, power supply, signal and interface settings
●
●
●
●
●
●
●
1.1
1.1.1
JP1 is for format selection: 0* = I
2
S, 1* = left justified
JP2 is for oversampling selection: 0 = 256 Fs, 1 = 384 Fs
JP3 is for gain selection: 0 = 0 dB, 1 = +24 dB, 0 = connect to outer side, 1 = connect to
inner side
+3.3 V selection: outer side = external +3.3 V, inner side = internal +3.3 V
Connect positive voltage of 12 V DC power supply to +Vcc pin and negative to GND
Connect positive voltage of 3.3 V DC power supply to +3V3 pin and negative to GND. If
the +3.3V selection is set to inner side, there is no need to connect these wires.
Connect STEVAL-CCA035V1 (APWLink USB interface board) to the J3 connector of
the STA335ML demonstration board or suitable I
2
S signals as shown in the schematic
diagram (DATA on pin 1, LRCK on pin 4 and BICK on pin 5).
Connect the S/PDIF signal cable to the RCA jack on the interface board, the other side
connecting to the signal source such as Audio Precision equipment or a DVD player.
Note that the voltage range of the DC power supply for Vcc is from 5 V to 18 V.
●
●
1.1.2
Output configuration
The STA335ML demonstration board is configured to 2.0 channels only and requires no
software to control it, so it is not necessary to connect STEVAL-CCA035V1 to the PC. When
the power supply, signal, interface and output are set up, push the RESET button, and the
STEVAL-CCA049V1 demonstration board is ready to operate properly.
Doc ID 023809 Rev 1
3/23
Test conditions and connections of demonstration board
AN4189
1.2
Figure 2.
Connections
Board terminals (top view)
External +3.3V
(No need if
+3.3V selection
is set to internal)
+3.3V
Selection
Vcc (5-18V)
L_CH Output
Connect to
interface board
R_CH Output
Oversampling
Selection
Gain
Selection
Format
Selection
Figure 3.
Speaker jack connection
R_CH Output
L_CH Output
4/23
Doc ID 023809 Rev 1
AN4189
Figure 4.
Test conditions and connections of demonstration board
Hookup of test connections with equipment
Audio Precision Equipment
Monitor
Output
to AP
S/PDIF
Signal
Digital Oscilloscope
TDS3034B Tektronix
I
2
S Input
STA335ML
Demo Board
AP Interface
(DC7V)
7V for LPT B’D
(DC3V3)
DC Power Supply
From 5V to 18V
Doc ID 023809 Rev 1
5/23
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