Am 25.09.2014 um 19:16 schrieb Grazvydas Ignotas:
The additional features the TWL6040 provides are as far as I know:
- integrated amplifier and speaker driver
Can that amp drive headphones?
yes.
In fact there are two amplifiers. One for >=16 Ohm headphones and one for >=8 Ohm speakers.
Connecting headphones directly to line out does not produce good sound, as seen on OMAP5 EVM.
Ah, that might explain your experiences.
The EVM has three 3.5mm jacks. One is for Line-IN. One is for Line-OUT. And the third one is for a headset/headphone - optionally with a microphone.
The Line-Out is *not* intended to drive any speaker or headset. It has no low-impedance amplifier and is only intended to drive an external amplifier. The data sheet defines a load resistance of min. 75kOhm.
And although it has differential + and - outputs only the + wire is connected.
So you should connect headsets and speakers to the headset jack. This is connected to the headset driver which can drive min. 16 Ohm and typ. 32 Ohms. This means, you should not connect 8 Ohms speakers to it or the system is run outside of spec.
BR, Nikolaus