Voltage Regulator on Audio Shield

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flightlessturd

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Hi,

I was wondering why there is an voltage regulator on the Audio Shield when the SGTL5000 can operate up to 3.6V and we already have 3.3v of regulated power from the Teensy?

Thanks!
 
Interesting question - my first thought was it takes 5V to offload the power draw from the Teensy - but it is fed only 3.3V. So then I assume it is to help assure cleaner power to the audio system?
 
From a previous thread its the 1.8v variant. Still unsure why you would need it if the sgtl5000 can run off 3.6V. Is there a lower noise perhaps at lower voltage?
 
flightlessturd said:
From a previous thread its the 1.8v variant. Still unsure why you would need it if the sgtl5000 can run off 3.6V. Is there a lower noise perhaps at lower voltage?
Click to expand...

As i understand the Datasheet and errata, it is not recomended to use the internal regulator (which can live with 3.6V) - instead the "external vddd" connection should be used.
Digital Voltage (If supplied externally).

External VDDD connection required for

new designs. 1.1 to 2.0 V
Click to expand...



http://www.nxp.com/products/media-a...o-codec:SGTL5000?fpsp=1&tab=Documentation_Tab
 
Take a look at the errata. It explains it better than I could do :)

Issue:
On some very rare combinations of parts and application
boards, and on a very small percentage of those rare
part/board combinations, sometimes the VDDD
internal regulator does not start up after IC power-up. This can occur
at any VDDIO and VDDA voltage level, and on either the
QFN20 or QFN32 part. The failure is a function of board
design and the slew rates of the power supplies, VDDIO
and VDDA. The failure does not occur if an external regulator is
used to supply VDDD.

Result:
The most noticeable symptom is that no IC
communication/control occurs, and that the I2C bus lines are
held in a low state. Power must be cycled to attempt another
power-up, and to attempt to regain IC communication. Note
that the same applies for SPI communication.

Workarounds:
New Designs
Use an external supply in the system or a separate regulator
to supply VDDD. This VDDD
supply must be between 1.1 V and 2.0

[.......]
Click to expand...
 
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