ST AN2013 APPLICATION NOTE

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AN2013

Application note

TS4994 low voltage differential audio power amplifier

Evaluation board user guidelines

Features

■ TS4994 low voltage differential audio power amplifier with programmable standby mode

■ Operating range from V

■ 1W output power @ V

■ Ultra low power consumption in standby mode (10nA)

■ 100dB PSRR @ 217Hz in grounded mode (Av=1V/V)

■ Near zero pop & click

■ Ultra low distortion (0.1%)

■ Module gain set at 1V/V

■ Thermal and short-circuit protection

Description

= 2.5V to 5.5V

= 5V, THD=1%, F= 1kHz, with 8Ω load

The DEMO TS4994 is an evaluation board designed for the TS4994 low power differential audio amplifier. The micropackage DFN10 (dual flat non leaded 10 pins) allows space saving and good thermal dissipation.

The differential gain is set at 1V/V and can be adapt ed if necessary with a modification of R1 to R4 values. Av=R2/R1=R4/R3 with R1=R3 and R2=R4.

On the board, you can set the Cn3 and Cn4 jumpers to modify the input configuration from capacitor coupled to common mode feedback. In capacitor coupled configuration, the -3dB cut-off frequency in Hz is:

1/(6.28xR1xC1) = 1/(6.28xR3xC2) with R in Ohm, C in Farad and C1=C2. For more detailed information about component calculation, refer to the TS4994 datasheet.

April 2007 Rev 3 1/6

www.st.com

Evaluation board connector configuration AN2013

1 Evaluation board connector configuration

Connectors Description

Cn1 and Cn2 Input signal connector (GND and active input signal).

Cn3 and Cn4

Cn5 Output signal connector (V

Cn6

Cn7 Standby control connector (GND, standby, V Cn8 Po wer connector (V

Caution: When you apply power supply through Cn8, DO NOT invert the polarity because it would

destroy the amplifier U1.

Connectors to modify input configuration (from capacitor coupled = no jumper to common mode feedback = short-circui t).

and Vo-)

Mode standby control connector (GND , standb y, V

). Allows you to select

standby mode active high or low.

and GND). Power supply voltage from 2.5V to 5.5V.

2 Schematic diagram

Figure 1. Schematic diagram of the TS4994 DFN10

Cn8

22k/1%

Vin-

Vin+

Bypass

Mode Stdby

1 2 3

GND GND

Cn7

VccVcc

1 2 3

Pos. Input

Neg. Input

Cn1

Cn2

GND

Cn3

100nF/10V 100nF/10V

Cn4

22k/1%

GND

C3 1uF/10V

Cn6

GND

Vcc

VCC

Standby GND

GND

C4 1uF/10V

GND GND

Bias

100nF/10V

TS4994IQ

Vo+

Vo-

Cn5

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AN2013 Schematic diagram

Table 1. Component list for the DEMO TS4994 DFN10

Designation Quantity Description

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

C5 1 100nF/16V, ceramic capacitors, 0603 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 2 pins header 2.54mm pitch Cn6 1 3 pins header 2.54mm pitch Cn7 1 3 pins header 2.54mm pitch Cn8 1 2 pins header 2.54mm pitch

J1 to J4 4 Jumper, 2.54mm pitch

R1 1 22kΩ, 1/16W 1% resistor, 0603

R2 1 22kΩ, 1/16W 1% resistor, 0603

R3 1 22kΩ, 1/16W 1% resistor, 0603

R4 1 22kΩ, 1/16W 1% resistor, 0603

U1 1 TS4994IQ (DFN10 package)

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Evaluation board layout AN2013

3 Evaluation board layout

The following figu res show the layers and the top view of the TS4994 demoboard.

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

Figure 4. Top view of demoboard

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AN2013 Revision history

Revision history

Date Revision Changes

3-Aug-2004 1 Initial release.

8-Dec-2006 2 Format update.

16- Apr-2007 3 Figure 4 updated (PCB is now Rev 1.1).

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AN2013

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