TS4999 View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TS4999

Filter-free stereo 2.8 W class D audio power amplifier with selectable 3D sound effects

STMicroelectronics 

Application information

4

Application information

TS4999

4.1

Differential configuration principle

The TS4999 is a monolithic fully-differential input/output class D stereo power amplifier. The

TS4999 also features 3D effect enhancement that can be switched on or off by one digital

pin. Additionally, since the load is connected differentially compared to a single-ended

topology, the output is four times higher for the same power supply voltage.

A fully-differential amplifier offers the following advantages.

● A high PSRR (power supply rejection ratio).

● A high common mode noise rejection.

● Virtually zero pop with no additional circuitry, giving a faster start-up time compared to

conventional single-ended input amplifiers.

● Easier interfacing with differential output audio DACs.

4.2

Note:

Gain settings

In the flat region of the frequency-response curve (no input coupling capacitor or internal

feedback loop + load effect), the differential gain can be set to 3.5, 6, 9.5 or 12 dB,

depending on the logic level of the G0 and G1 pins, as shown in Table 11.

Table 11. Gain settings with G0 and G1 pins

G1

G0

Gain (dB)

0

0

3.5

0

1

6

1

0

9.5

1

1

12

Gain (V/V)

1.5

2

3

4

Between pins G0, G1 and GND there is an internal 300 kΩ (+/-20%) resistor. When the pins

are floating, the gain is 6 dB. In full standby (left and right channels OFF), these resistors

are disconnected (HiZ input).

4.3

3D effect enhancement

The TS4999 features 3D audio effects which can be switched off and switched on through

input pin 3D when used as a digital interface. The relation between the logic level of this pin

and the on/off 3D effect is shown in Table 3 on page 4 and Table 7 on page 6.

The 3D audio effect evokes the perception of spatial hearing of stereo audio signals and

improves this effect in cases where the stereo speakers are too close to each other, such as

in small or portable devices.

The perceived amount of 3D effect also depends on many factors such as speaker position,

distance between speakers, listener/frequency spectrum of the audio signal, as well as the

difference of signal between the left and right channel.

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