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DA7218 unused input or output components


8 months ago

Posted by jbright 20 points 3 replies
  1. Can we use the headphone output as a Line out, biased above ground, and not use the charge pump, or is the charge pump always required whenever output is used?
  2. If we're not using the charge pump, we can remove components on HPCSN, HPCFP, HPCFN, but do we still need the capacitor on HPCSP?
  3. If we're not using the input, do we need to keep the components on MICBIAS1, MICBIAS2?

Any other components that we can remove when input or output is not being used?

7 months ago


Hello Johnathan,

Thank you for reaching out to us

1. You need to connect the Charge Pump Pins  to generate the supplies for the amplifier. (Please see attached a snippet from the DS)

2. When not using the charge pump , the HPCSP has to be powered ON

3. No, not necessary

Also the DA7212 has a Line out driver, is that interesting for you? 

Please let me know if you have any further questions

Kind Regards


Attachment Size
Charge_pump_pins.png 34.19 KB

4 months ago

We built the circuit without the flying capacitor, but the outputs are ground-referenced and don't go below 0, so the output is half-wave rectified.  Is there something else we need to do to get the outputs biased above ground?  I can't find any registers to set this.

4 months ago

Maybe the GND_SENSE output needs to be connected to a mid-point bias instead of a ground?  Then the HPL/HPR outputs will be mid-biased?  Datasheet doesn't really mention this, though.

The datasheet says "If the charge pump is not being used", but maybe it means "if the headphone output is not being used"?