Contents
AN3383
Contents
1
Functional description of the demonstration board . . . . . . . . . . . . . . . 4
1.1
1.2
1.3
Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Output configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Schematic and block diagrams, PCB layout, bill of material . . . . . . . . . . . . 5
2
3
4
Test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Thermal test results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Design guidelines for schematic and PCB layout . . . . . . . . . . . . . . . . 16
4.1
Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.1.1
4.1.2
4.1.3
Main driver for selection of components . . . . . . . . . . . . . . . . . . . . . . . . 16
Decoupling capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Output filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
4.2
PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
5
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
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AN3383
List of figures
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
Figure 40.
Figure 41.
Figure 42.
Figure 43.
STA350BW 2.0-channel demonstration board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Schematic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Block diagram of test connections with equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Top view of PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Bottom view of PCB layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Efficiency (2 channels, BTL configuration), V
CC
= 26 V, R
L
= 6 ohm . . . . . . . . . . . . . . . . . . 9
Efficiency (2 channels, BTL configuration), V
CC
= 26 V, R
L
= 8 ohm . . . . . . . . . . . . . . . . . 10
Output power vs. supply voltage, R
L
= 6 ohm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Output power vs. supply voltage, R
L
= 8 ohm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Frequency response, V
CC
= 24 V, R
L
= 6 ohm, 0 dB (Pout = 1 W) . . . . . . . . . . . . . . . . . . 11
Crosstalk, V
CC
= 24 V, R
L
= 6 ohm, 0 dB (Pout = 1 W) . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
SNR, V
CC
= 24 V, R
L
= 6 ohm, 0 dB (Pout = 1 W) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
THD vs. frequency, V
CC
= 24 V, R
L
= 6 ohm, Pout = 1 W . . . . . . . . . . . . . . . . . . . . . . . . . 12
FFT (0 dBFS), V
CC
= 24 V, R
L
= 6 ohm, 0 dBFS (Pout = 1 W) . . . . . . . . . . . . . . . . . . . . . 13
FFT (-60 dBFS), V
CC
= 24 V, R
L
= 6 ohm, 0 dBFS (Pout = 1 W) . . . . . . . . . . . . . . . . . . . . 13
THD vs. output power, V
CC
= 24 V, R
L
= 6 ohm, f = 1 kHz . . . . . . . . . . . . . . . . . . . . . . . . 13
Output power = 2 x 5 W, V
CC
= 26 V, load = 6 ohm, frequency = 1 kHz . . . . . . . . . . . . . . 14
Output power = 2 x 10 W, V
CC
= 26 V, load = 6 ohm, frequency = 1 kHz . . . . . . . . . . . . . 14
Output power = 2 x 15 W, V
CC
= 26 V, load = 6 ohm, frequency = 1 kHz . . . . . . . . . . . . . 15
Output power = 2 x 38 W, V
CC
= 26 V, load = 8 ohm, frequency = 1 kHz . . . . . . . . . . . . . 15
Output filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Power dissipated over the series resistance [P = C*f*(2*V)
2
]. . . . . . . . . . . . . . . . . . . . . . . 17
Power dissipated over the series resistance [P = C*f*2(V
2
)] . . . . . . . . . . . . . . . . . . . . . . . 17
Damping network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Main filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Recommended power-up and power-down sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Snubber network soldered as close as possible to the related IC pin . . . . . . . . . . . . . . . . 19
Electrolytic capacitor used first to separate the V
CC
branches . . . . . . . . . . . . . . . . . . . . . . 20
Path between V
CC
and ground pin minimized in order to avoid inductive paths . . . . . . . . 20
Large ground planes on the top and bottom sides of the PCB . . . . . . . . . . . . . . . . . . . . . . 21
PLL filter soldered as close as possible to the FILT pin . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Symmetrical paths created for output stage (for differential applications) . . . . . . . . . . . . . 22
Coils separated in order to avoid crosstalk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
V
CC
filter for high frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Decoupling capacitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Snubber filter for spike high frequency in PWM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Correct common-mode and differential snubber placement . . . . . . . . . . . . . . . . . . . . . . . . 24
Correct output routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Comparison of output routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Thermal layout with large ground (1/3 for top and bottom layers) . . . . . . . . . . . . . . . . . . . 26
Thermal layout with large ground (2/3 for thermal and soldering holes). . . . . . . . . . . . . . . 26
Comparison of thermal layout (top layer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Comparison of thermal layout (bottom layer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Doc ID 018691 Rev 1
3/29
Functional description of the demonstration board
AN3383
1
Functional description of the demonstration board
The following terms used in this application note are defined as follows:
●
●
●
●
●
THD+N vs. Freq: Total harmonic distortion plus noise versus frequency curve
THD+N vs. Pout: Total Harmonic Distortion (THD) plus noise versus output power
S/N ratio: Signal-to-noise ratio
FFT: Fast Fourier Transform Algorithm (method)
CT: Channel separation L to R, or R to L channel crosstalk
Audio Precision (System 2700) by AP Co., USA)
DC power supply (4.5 V to 26 V)
Digital oscilloscope (TDS3034B by Tektronix)
PC (with APWorkbench GUI control software installed)
The equipment used includes the following:
●
●
●
●
1.1
Connections
Power supply signal and interface connection
1.
2.
3.
Connect the positive voltage of 24V DC power supply to the +Vcc pin and negative to
GND.
Connect the APWorkbench board to the J1 connector of the STA350BW demonstration
board.
Connect the S/PDIF signal cable to the RCA jack on the APWLink board, connecting to
the signal source such as Audio precision or DVD player.
Note:
The voltage range of the DC power supply for V
CC
is 4.5 V to 26 V.
1.2
Output configuration
The STA350BW demo board is specifically configured in 2 BTL channels. For the software
setup, please refer to the APWUserManualR1.0.pdf.
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Doc ID 018691 Rev 1
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