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Application note
TS4990 low voltage audio power amplifier
Evaluation board user guidelines
TS4990 features
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TS4990 low voltage audio power amplifier with active low standby mode
Operating from V
CC
=2.2V to 5.5V
1.2W output power @ V
CC
=5V, THD=1%, F=1kHz, with 8Ω load
Ultra low power consumption in standby mode (10nA)
62dB PSRR @ 217Hz in grounded mode (Av=2V/V)
Near zero pop & click
Ultra low distortion (0.1%)
Module gain set at 2V/V
Thermal and short circuit protection
Description
The DEMO TS4990 is an evaluation board designed for the TS4990 low power audio
amplifier. The micropackage DFN8 (dual flat non leaded 8 pins) allows space saving and
good thermal dissipation.
The BTL gain is set at 2V/V and can be adapted if necessary with a modification of R1 or R2
values.
On the board, R3 and C3 component locations are empty to allow you to modify the input
configuration from single ended to differential. For differential mode, R4 must be modified.
The C1 component location is also empty so that you can add a low pass filter if required.
More information about component calculations is available in the TS4990 datasheet.
November 2006
Rev 3
1/5
www.st.com
Connector configuration
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Connector configuration
Caution:
When you apply power supply through Cn1, DO NOT invert the polarity because it would
destroy the amplifier U1.
Connector
Cn1
Cn2 and Cn3
Cn4
Cn5
Description
Power connector (V
CC
and GND). Power supply voltage from 2.2V to 5.5V.
Input signal connector (GND and active input signal).
Output signal connector (V
out1
and V
out2
).
Standby control connector (V
CC
, standby, GND). A short-circuit between V
CC
and standby puts U1 in operation mode. A short-circuit between GND and
Standby puts U1 in standby mode.
Figure 1.
Schematic diagram
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Component list for the DEMO TS4990/DFN
Component list for the DEMO TS4990/DFN
Designation
C1
C2
C3
C4
C5
C6
Cn1
Cn2
Cn3
Cn4
Cn5
J1
R1
R2
R3
R4
U1
Quantity
0
1
0
1
1
1
1
1
1
1
1
1
1
1
0
1
1
Description
Unconnected, ceramic capacitors, 0603
100nF/16V, ceramic capacitors, 0603
Unconnected, ceramic capacitors, 0603
1μF/50V, electrolytic capacitor
100nF/16V, ceramic capacitors, 0603
1μF/50V, electrolytic capacitor
2 pins header 2.54mm pitch
2 pins header 2.54mm pitch
2 pins header 2.54mm pitch
2 pins header 2.54mm pitch
3 pins header 2.54mm pitch
Jumper, 2.54mm pitch
22k, 1/16W 1% resistor, 0603
22k, 1/16W 1% resistor, 0603
Unconnected, 1/16W 1% resistor, 0603
0R, 1/16W 1% resistor, 0603
TS4990IQ (DFN8 package)
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Evaluation board layout
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Evaluation board layout
The following schematics show the different layers and the top view of the evaluation board.
Figure 2.
PCB top layer view
Figure 3.
PCB bottom layer view
Figure 4.
Top view of demo board
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