ST AN2013 APPLICATION NOTE

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

CC

= 5V, THD=1%, F= 1kHz, with 8Ω load

CC

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-)

o+

Mode standby control connector (GND , standb y, V

). Allows you to select

CC

standby mode active high or low.

).

CC

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

CC

2 Schematic diagram

Figure 1. Schematic diagram of the TS4994 DFN10

Cn8

R2

22k/1%

R4

22k/1%

Vin-

2

Vin+

4

Bypass

5

Mode Stdby

1
2
3

GND GND

1

Cn7

VccVcc

1
2
3

Pos. Input

Neg. Input

Cn1

Cn2

GND

GND

Cn3

J1

C1

100nF/10V
100nF/10V

C2

J2

Cn4

R1

22k/1%

R3

22k/1%

+

GND

C3
1uF/10V

Cn6

J3

GND

J4

Vcc

9

VCC

-

+

Standby
GND

73

GND

+

C4
1uF/10V

GND GND

Bias

C5

100nF/10V

TS4994IQ

Vo+

Vo-

U1

10

6

Cn5

2/6