TS2007FC View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

TS2007FC

3 W filter-free class D audio power amplifier with 6 or 12 dB fixed gain select

STMicroelectronics 

Application information

4

Application information

TS2007FC

4.1

Differential configuration principle

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

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

average it at VCC/2 in the range of DC common mode input voltage. This allows the device

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

power. In addition, as 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 has the following advantages.

● High PSRR (power supply rejection ratio).

● High CMRR (common mode noise rejection).

● Virtually zero pop without additional circuitry, giving a faster start-up time than

conventional single-ended input amplifiers.

● Easy interfacing with differential output audio DACs.

● No input coupling capacitors required since there is a common mode feedback loop.

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 either 6 or 12 dB depending

on the logic level of the GS pin.

Table 11. GS pin gains

GS pin

1

0

Gain (dB)

6 dB

12 dB

Gain (V/V)

2

4

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

the gain is 6 dB. In standby mode, this internal resistor is disconnected (HiZ input).

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 Vicm limitation of the input stage (see Table 2: Operating conditions), the common

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

4.4

20/28

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 has a greater effect.

Cin and the input impedance Zin form a first-order high-pass filter with a -3 dB cut-off

frequency (see Table 5 to Table 9).

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