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TS2012

Application information

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4

Application information

4.1

Differential configuration principle

The TS2012 is a monolithic fully-differential input/output class D power amplifier. The

TS2012 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 with 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 with

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 6, 12 18, or 24 dB depending

on the logic level of the G0 and G1 pins, as shown in Table 9.

Note:

Between pins G0, G1 and GND there is an internal 300 k

Ω (±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

Common mode feedback loop limitations

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), the common

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

Table 9. Gain settings with G0 and G1 pins

G1

G0

Gain (dB)

Gain (V/V)

00

62

01

12

4

10

18

8

1

1

24

16