ST AN2479 APPLICATION NOTE
AN2479
Application note
STA333ML demo board application note
Introduction
The purpose in this document is:
■ to describe how to connect the STA333ML demo board,
■ how to evaluate the demo board performance with electrical curve data,
■ how to avoid critical board and layout issues.
Application note can be configured to the 2.0 channels only. Both of the 2 channels are in
BTL mode. Each channel can deliver 20 W @ THD = 10% when Vcc = 18V and 8 load. It is
a total solution for the digital audio power amplifier in a TV application.
All the test items and graph data in this document are measured by audio precision
equipment. The test data shown in this document contains, for example, output power
versus Vcc, frequency response, THD+N versus frequency, THD+N versus output power,
FFT.
December 2006 Rev 1 1/42
www.st.com
Contents AN2479
Contents
1 Test condition and connection of demo board . . . . . . . . . . . . . . . . . . . 3
1.1 Test condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1.1 Jumper, power supply, signal and interface setting . . . . . . . . . . . . . . . . . 3
1.1.2 Output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Equipment requirement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Connection method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.1 Speaker jack connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3.2 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4 PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.1 Top view of PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.4.2 Bottom view of PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5 BOM list . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.5.1 Test connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Test curve report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Frequency Response . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 THD versus frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.2.1 THD versus output power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.3 FFT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
2.4 Cross talk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3 Design guideline for PCB schematic and layout . . . . . . . . . . . . . . . . . 28
3.1 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.1.1 Main driver for components selection . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.2 Decoupling capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.2.1 Output filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3.3 Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
4 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
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AN2479 Test condition and connection of demo board
1 Test condition and connection of demo board
1.1 Test condition
1.1.1 Jumper, power supply, signal and interface setting
1. JP1: format selection. 0
2. JP2: oversampling selection. 0 = 256 Fs, 1 = 384 Fs.
3. JP3: gain selection. 0 = 0 dB, 1 = +24 dB.
4. +3.3 V selection. Outer side = external +3.3 V, inner side = internal +3.3 V
5. Connect + voltage of 12 V DC power supply to +Vcc pin and negative to GND.
6. Connect + voltage of 3.3 V DC power supply to +3.3 V pin and negative to GND. If the
+3.3 V selection is set to the inner side, do not connect this wire.
7. Connect GUI AP interface board to the J3 connector of STA333ML demo board.
8. Connect the S/PDIF signal cable to the RCA jack on the interface board, The input
coming from the signal source such as Audio precision or DVD player.
9. The voltage range of the DC power supply for Vcc is from 5 V to 18 V.
(a)
= I2S, 1
(a.)
= left justified.
1.1.2 Output configuration
STA333ML demo board can be configured to 2.0 channels and do not require software
control. It is not necessary to connect the AP interface to the PC. When the power supply,
signal, interface and output have been setup, push the RESET button which allows the
STA333ML demo board to function.
1.2 Equipment requirement
● Audio Precision (System 2700) by AP Co., USA)
● DC power supply (With 5V to 18V)
● Digital oscilloscope (TDS3034B) by Tektronix
● PC
a. 0: connect to outer side, 1: connect to inner side.
3/42
Test condition and connection of demo board AN2479
1.3 Connection method
Top view of demo board.
Figure 1. Block diagram
External 3.3 V
(not required if +3.3 V
selection is set to internal)
+3.3 V
selection
Vcc (5-18 V)
L_CH output
Connect to
interface board
Oversampling
selection
Gain
selection
1.3.1 Speaker jack connection
Figure 2. Block diagram
R_CH output
Format
selection
L_CH outputR_CH output
4/42
AN2479 Test condition and connection of demo board
1.3.2 Schematic
Figure 3. Schematic diagram
1.4 PCB Layout
1.4.1 Top view of PCB layout
Figure 4. Top layout
5/42
Test condition and connection of demo board AN2479
1.4.2 Bottom view of PCB layout
Figure 5. Bottom layout
1.5 BOM list
Table 1. BOM
Item
no.
1 CCAP CCAP0603 100 n, 50 V, +/- 10 % 18
2 CCAP CCAP0603 1 n, 50 V, +/- 10 % 1 C5 Murata
3 CCAP CCAP0603 4.7 n, 50 V, +/- 10 % 1 C8 Murata
4 CCAP CCAP0603 680 p, 50 V, +/- 5 % 1 C9 Murata
5 CCAP CCAP0603 330 p, 50 V, +/- 10 % 2 C15, C21 Murata
6 CCAP CCAP0603 10 n, 50 V, +/- 10 % 6 C27, C28, C29, C30, C31, C32 Murata
7 CCAP CCAP1206 1 µ, 50 V 2 C13, C14 Murata
8 ECAP D = 10 mm 1000 µ, 25 V 1 C10 Rubycon
9ECAP D = 7mm22µ, 16 V 1 C33 Rubycon
10 ECAP D = 5 mm 2.2 µ, 25 V 1 C36 Rubycon
11 Chip bead L0805 600 ohm @ 100 MHz 2 BD1, BD2 Murata
12 CRES R0603 10 k +/- 5 % 2 R1, R3 Murata
13 CRES R0603 0 ohm +/- 5 % 1 R2 Murata
14 CRES R0603 2.2 k +/- 5 % 1 R4 Murata
15 CRES R1206 22 ohm +/- 5 % 2 R5, R8 Murata
Type Package Description Qty Reference code Manufacturer
C1, C2, C3, C4, C6, C7, C11,
C12, C16, C17, C18, C19, C22,
C23, C24, C25, C34, C35
Murata
16 CRES R1206 6.2 ohm +/- 5 % 4 R6, R7, R9, R10 Murata
6/42
AN2479 Test condition and connection of demo board
Table 1. BOM
Item
no.
17 Test point Through hole 1 x 5 2.54 mm pitch 1 J2 Any source
18 Connector Through hole
19 Jumper Through hole 1 x 3 2.54 mm pitch 4 JP1, JP2, JP3, JP4 Any source
20 IC Through hole STA333ML 1 U1 ST
21 CAP Through hole 470 n 2 C20, C26
22 Connector Through hole WP4-15 1 J1 Song Cheng
23 Connector Through hole FFKDS/H1-5.08 3 J5, J6, J7
24 Connector Through hole FFKDSA1/H1-7.62 1 J4
25 COIL Through hole 22 µH 4 L1, L2, L3, L4 Kwang Sung
26
Type Package Description Qty Reference code Manufacturer
Ta c t
switch
2 x 8 2.54 pitch male
connector
Through hole 6 x 6 Tact switch 1 SW
1 J3 Any source
Phoenix
contact
Phoenix
contact
1.5.1 Test connection
Figure 6. Block diagram of test equipment
Output
to AP
STA333ML
demo board
From 5 V to 18 V
Audio precision equipment
S/PDIF
signal
2
I
S signal
Digital oscilloscope
TDS3034B Tektronix
(DC3V3)
(DC7V)
7V for LPT B’D
DC power supply
Monitor
AP interface
7/42
Test curve report AN2479
2 Test curve report
Figure 7. Efficiency versus output power
Efficiency
100.00
90.00
80.00
70.00
60.00
η(%)
50.00
40.00
30.00
20.00
10.00
0.00
1 2 3 4 5 6 7 8 9 1011121314151617181920
Condition: R LOAD =8 ohm; VCC=18 V
Figure 8. Output power versus Vcc
Output Power@1%THD vs. Vcc
30
25
20
15
10
5
Output Power (W)
0
5 6 7 8 9 10 11 12 13 14 15 16 17 18
Vcc (V)
Output Power (W)
Rl=8 Ohm
Rl=6 Ohm
Rl=4 Ohm
8/42
AN2479 Test curve report
A
k
k
Figure 9. Output power@10% THD vs. supply voltage
Output Power@10%THD vs. Vcc
35
30
25
20
15
10
5
Output Power (W)
0
5 6 7 8 9 101112131415161718
Vcc (V)
Rl=8 Ohm
Rl=6 Ohm
Rl=4 Ohm
2.1 Frequency Response
Figure 10. 18 V 4 ohm 0 dB: Pout = 1 W@ 1 KHz filter: L = 10 uH, C = 1 uF
+3
+2
+1
d
B
+0
r
-1
-2
-3
20
50 100 200 500 1k 2k 5k 10
20
Hz
9/42
Test curve report AN2479
r
A
k
k5k10k
z
+3
A
k
Figure 11. 18 V 6 Ohm 0 dB: Pout = 1 W @ 1 KHz filter: L = 15 uH, C = 680 nF
+3
+2
+1
d
B
+0
-1
-2
-3
20 20
50 100 200 500 1k2
H
Figure 12. 18 V 8 Ohm 0 dB: Pout = 1 W @ 1 KHz filter: L = 22 uH, C = 470 nF
+2
+1
d
B
+0
r
-1
-2
-3
20
50 100 200 500 1k 2k 5k 10k
20
10/42
AN2479 Test curve report
020k
k2k5k10k
k
Figure 13. 6 Ohm Pout = 1 W
10
5
2
1
0.5
%
0.2
0.1
0.05
0.02
0.01
2
50 100 200 500 1
Vcc=5 V
Vcc=18 V Vcc=12 V
2.2 THD versus frequency
Figure 14. 4 Ohm Pout = 1 W
10
5
2
1
0.5
%
0.2
0.1
0.05
0.02
0.01
20 20
50 100 200 500 1k 2k 5k 10k
Vcc=5 V
Vcc=18 V
11/42
Test curve report AN2479
0
5
20.5125%
m30
m
51020
W
Figure 15. 8 Ohm Pout = 1 W
10
5
2
1
0.5
Vcc=5 V
%
0.2
0.1
0.05
0.02
Vcc=12 V
0.01
20 20k50 100 200 500 1k 2k 5k 10k
2.2.1 THD versus output power
Figure 16. 4 Ohm (1/2)
1
5V
0.
0.1
0.0
0.02
0.01
100
200
8V
500m12
Vcc=18 V
12V
16V
12/42
AN2479 Test curve report
0
2
5
20.51 2 5
%
m30
m
m12
51020
W
0
2
5
20.51 2 5
%
m
m
2
51020
W
0
0
2
5
20.51 2 5
%
m30
m
m12
51020
W
Figure 17. 4 Ohm (2/2)
1
6V
10V
0.
0.1
0.0
0.0
0.01
100
14V
500
18V
200
Figure 18. 6 Ohm (1/2)
1
5V
0.
0.1
0.0
0.0
0.01
100m200
Figure 19. 6 Ohm (2/2)
1
0.
0.1
0.0
0.0
0.01
100
6V
200
500
10V
8V
500
12V
1
14V
16V
18V
3
13/42
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