Other Parts Discussed in Thread: TPA6111A2
Hi,
I'm trying to design a headphone amplifier based on the TPA6110A2.
This is my schematic:
The audio plugs are actually jacks on the PCB.
I'm testing with a 3.3V power supply and with a 1cell Lithium Ion, with 4.2V max.
There is no output whatsoever.
I'm measuring the audio input signal on C1 and before R1, but after R1, at the junction with R3 I'm measuring 2V DC level.
On the other side, there's audio signal on C11 and before R2, but after R2, at the junction with R4 I'm measuring 1V DC level.
My bypass is not VDD/2, as I'm measuring around 500mV on CB (C3).
Power draw is 90mA at 3.3V while doing nothing, even with both audio connectors unplugged.
With the shutdown pulldown resistor in place I'm measuring around 800mV at the SHUTDOWN pin.
Such a simple design, yet I've clearly made a mistake somewhere. I've tried messing around with the gain resistors but to no luck.
I'm sorry, maybe I missed something, I would like some help please..
Thank you,