Application information

TS2007

22/29

Doc ID 13123 Rev 4

4

Application information

4.1

Differential configuration principle

The TS2007 is a monolithic fully-differential input/output class D power amplifier. The

TS2007 also includes a common-mode feedback loop that controls the output bias value to

average it at VCC/2 for any DC common-mode input voltage. This allows the device to

always have a maximum output voltage swing, and by consequence, maximize the output

power. Moreover, as the load is connected differentially compared to a single-ended

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

The advantages of a full-differential amplifier are:

●

High PSRR (power supply rejection ratio)

●

High common-mode noise rejection

●

Virtually zero pop without additional circuitry, giving a faster startup time compared to

conventional single-ended input amplifiers

●

Easier interfacing with differential output audio DAC

●

No input coupling capacitors required thanks to common-mode feedback loop

4.2

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 either 6 or 12 dB depending

on the logic level of the GS pin:

Note:

Between the GS pin and VCC there is an internal 300 kΩ resistor. When the pin is floating

the gain is 6 dB.

4.3

Common-mode feedback loop limitations

As explained previously, the common-mode feedback loop allows the output DC bias

voltage to be averaged at VCC/2 for any DC common-mode bias input voltage.

Due to the Vic limitation of the input stage (see Table 2: Operating conditions on page 3), the

common-mode feedback loop can fulfill its role only within the defined range.

4.4

Low frequency response

If a low frequency bandwidth limitation is required, it is possible to use input coupling

capacitors. In the low frequency region, the input coupling capacitor Cin starts to have an

effect. Cin forms, with the input impedance Zin, a first order high-pass filter with a -3 dB cutoff

frequency (see Table 5 to Table 9).

GS

Gain (dB)

Gain (V/V)

16 dB

2

0

12 dB

4

Obsolete

Product(s)

- Obsolete

Product(s)