ST AN1766 APPLICATION NOTE

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Application note

TS4990 low voltage audio power amplifier

Evaluation board user guidelines

TS4990 features

■ TS4990 low voltage audio power amplifier with active low standby mode

■ Operating from V

■ 1.2W output power @ V

■ 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

=2.2V to 5.5V

=5V, THD=1%, F=1kHz, with 8Ω load

AN1766

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 ad apted if necessary with a modificati on 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 AN1766

Connector configuration

Caution: When you apply power supply through Cn1, DO NOT invert the polarity because it would

destroy the amplifier U1.

Connector Description

Cn1 Pow er connector (V

and GND). Power supply voltage from 2.2V to 5.5V.

Cn2 and Cn3 Input signal connector (GND and active input signal). Cn4 Output signal connector (V

Standby control connector (V

Cn5

and standby puts U1 in operation mode. A short-circuit between GND and

and V

out1

, standby, GND). A short-circuit between VCC

out2

Standby puts U1 in standby mode.

Figure 1. Schematic diagram

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AN1766 Component list for the DEMO TS4990/DFN

Component list for the DEMO TS4990/DFN

Designation Quantity Description

C1 0 Unconnected, ceramic capacitors, 0603 C2 1 100nF/16V, ceramic capacitors, 0603 C3 0 Unconnected, ceramic capacitors, 0603 C4 1 1μF/50V, electrolytic capacitor C5 1 100nF/16V, ceramic capacitors, 0603

C6 1 1μF/50V, electrolytic capacitor Cn1 1 2 pins header 2.54mm pitch Cn2 1 2 pins header 2.54mm pitch Cn3 1 2 pins header 2.54mm pitch Cn4 1 2 pins header 2.54mm pitch Cn5 1 3 pins header 2.54mm pitch

J1 1 Jumper, 2.54mm pitch R1 1 22k, 1/16W 1% resistor, 0603 R2 1 22k, 1/16W 1% resistor, 0603 R3 0 Unconnected, 1/16W 1% resistor, 0603 R4 1 0R, 1/16W 1% resistor, 0603 U1 1 TS4990IQ (DFN8 package)

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Evaluation board layout AN1766

Evaluation board layout

The following schematics show the different layers and the top view of the evaluat ion board.

Figure 2. PCB top layer view Figure 3. PCB bottom layer view

Figure 4. Top view of demo board

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AN1766

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