TAD5242: Error in EVM board schematics?

Sergey Odinokov

Prodigy 120 points

Part Number: TAD5242

Tool/software:

Hello,

According to TAD5242 DS:

1. All AVSS pins must me connected to ground

2. Pin 14 is AVSS

But according to EVM board schematics, https://www.ti.com/lit/pdf/SLAU904

Pin 14 is connected to capacitance and named MICBIAS instead of AVSS, and all AVSS pins are all left unconnected.

What is correct?

Regards

8 months ago

+1 Daveon Douglas 8 months ago

TI__Mastermind 27280 points

Hi S,

It appears to be an error with the symbol regarding the MICBIAS name, thanks for catching it.

However, the traces for pin 15,16,17,18 are connected to jumpers that allow for a connection to GND. From a design perspective, when they are trimming the silicon to be a DAC or an ADC they are essentially "NC" (no-circuiting) these pins which allow them to be left floating. We recommend them to be tied to GND. Pins 14-18 all have paths to GND but if left unconnected will not impact performance of the device.

0 Sergey Odinokov 8 months ago in reply to Daveon Douglas

Prodigy 120 points

Hello, I thought red cross means "do not mount", so, only pin 14 has connection to jumper J8 (wrong one for DAC case) while pins 15-18 are floating on the diagram. Anyway, your answer clearly explains why it is not an issue.

Regards,

0 Daveon Douglas 8 months ago in reply to Sergey Odinokov

TI__Mastermind 27280 points

Hi sergey,

Pins 15-18 have J78-79 and J52-53 jumpers that allow connection to ground. When purchasing an EVM, these jumpers should also be populated by default.

Pin 14 is essentially AC-coupled to GND.

The red cross does mean 'do not mount'.

0 Sergey Odinokov 8 months ago in reply to Daveon Douglas

Prodigy 120 points

Daveon, Pins 15-18 have J78-79 and J52-53 jumpers only if resistors R9-12 are mounted, right? But they are red crossed for TAD5242 case, and you confirmed it means they are not soldered. Therefore pins 15-18 are floating. Am I wrong?

0 Sergey Odinokov 8 months ago in reply to Sergey Odinokov

Prodigy 120 points

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TAD5242: Error in EVM board schematics?