TLV320DAC3203: Reference decoupling capacitor

Hello, Yaita-san,

As mentioned in the 2.10 section of Reference Guide, "the TLV320DAC3203 achieves its low-noise performance by internally generating a low-noise reference voltage". In order to get a low-noise reference voltage, at least you would require a 1uF decoupling capacitor. However, we suggest to use a 10uF capacitor in order to get a better low-noise performance.

You must consider that there's a trade off between noise filtering and power up time. Using a 10uF capacitor provides a better low noise performance, but it takes more time to power up since the settling time is associated to the decoupling capacitor value. The settling time is approximately 1 second when a 1uF capacitor is used. If a 10uF capacitor is used, this settling time reaches approximately 2.5 seconds.

Fortunately, when a faster power up is required, the TLV320DAC3203 may be configured by page 1, register 123. It allows a fast-charge option, so the charging time may be between 40ms and 120ms. In this case, an additional 125uA AVDD current is consumed. (For more details, please take a look at the Reference Voltage section of reference guide)

I hope this helps you. Please let me know if you have additional questions or comments.

Best regards,
Luis Fernando Rodríguez S.