Texas Instruments TPA301 User Manual download pdf (Page 24)

Inputs and Outputs

3-10

Details

3.3.5 Inputs and Outputs

The TI plug-n-play audio amplifier evaluation platform is equipped with several

standard conectors for audio inputs and outputs.

3.3.5.1 Inputs

In most cases, audio signals enter the platform through either a pair of RCA

phono jacks (J3 and J5) or a miniature (1/8″) stereo phone jack (J4). Certain

signal conditioning and amplifier EVMs, however, may have additional signal

input connectors mounted on the module circuit board.

The platform audio signal input jacks (J3, J4, and J5) are of the closed-circuit

type, grounding the signal input lines when no plugs are inserted.

3.3.5.2 Outputs

Amplified audio output signals leave the platform through left and right RCA

phono jacks (J7 and J9), left and right pairs of compression connectors for

stripped speaker wires (J8), and optionally, through a miniature (1/8″) stereo

phone jack (J10), for headphones.

The audio output lines from the power amplifiers are separate all the way to

the edge of the platform (output jacks J7, J8, and J9) — the OUT– lines from

the power amplifier sockets are not tied to each other or to platform ground.

This allows the TPA301 power amplifier EVMs to operate in the highly-efficient

bridge-tied load configuration.

The headphone jack (J10) is capacitively coupled to source select switch S3,

which connects J10 to the output lines of either the headphone amplifier

socket or the power amplifier sockets (Figure 3–5). When the TPA301 output

signal is routed to J10 by S3, signals output via J10 are returned to platform

ground when a plug is inserted (Figure 3–7), requiring single-ended operation

of the power amplifiers.

Figure 3–7. Typical Headphone Plug

Left Right GND

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Texas Instruments TPA301 User Manual Page 24