DAC7760: Handling DVDD

Howdy Jintai,

I believe the inquiry is regarding a schematic review of the above attachment. We will perform a review on our end and provide feedback in a future update.

Best Regards,
Matt

Hi Jintai,

The copy of the schematic provided above is a small 'snippet' of the schematic included in TIDUBL9A.  In this schematic, the "DVDD-EN" pin is left floating, which enables the internal supply.  This internal supply voltage is brought out to the DVDD pin, which uses sufficient bypass to improve stability and noise performance of the supply. Another practical illustration of this configuration is provided in page 47 of the DAC7760 DS.  

Regarding the MUX36S08 device, please note that the "On-Resistance" of the multiplexer may also affect the accuracy of the voltage output.  Page 15 of the MUX36S08 states that this on-resistance varies with input voltage and supply voltage, therefore different DAC output voltages may results in small variations of Ron.

Best Regards,

Matt

Thanks for your support.
Regarding our project the MUX36S08 is not necessary therefore the DVDD-EN pin is left floating and the REFIN and REFOUT pins are connected as the schematic in page 47 of the DAC7760, how is DVDD pin handled?

Howdy Jingtai,

You can connect decoupling capacitors on the DVDD pin of the DAC7760 device. Typical values include 0.1uF and 1uF capacitors connected from DVDD to GND.

Best Regards,
Matt

Howdy Jintai,

Glad to help :)

Best Regards,
Matt