Inquiries regarding DAC8831

Atsushi Okui

Genius 4015 points

Other Parts Discussed in Thread: DAC8831, DAC8831EVM, OPA172

Hello, all

Now we have some inquiries regarding DAC8831 from our customer.

Please refer to the items below, and feedback us with your comment.

1) Inquiry regarding output behaviour when LDAC pin tied to GND.

When using this device with LDAC pin tied to GND, the signal feedbacked into REFB via differential OpAMP seems to be reseted when /CS pin goes low. After /CS pin goes high again, the signal is recovered as normal operation.

Here is the waveform captured incase inputting 8000(HEX) via SPI interface to this device.

Please let us clarify whether the behaviour above is correct.

2) Inquiry regarding VREF setting.

Incase willing to output +/- 2.5V output via differential OpAMP, what is recommended VREF-S and VREF-F voltage to be applied. We are going to use this device with VDD=5V.

We thank you in advance for your information.

Best regards,

over 10 years ago

0 Kevin Duke over 10 years ago

TI__Mastermind 46290 points

Okui-san,

To answer your first question, can you provide a schematic for the existing design?

To achieve +/-2.5V output swing, the reference input should be 2.5V. The force and sense lines may be utilized as a kelvin connection as shown in the DAC8831EVM User's Guide or simply directly connected to one another close to the pins and driven with the same potential.

0 Atsushi Okui over 10 years ago in reply to Kevin Duke

Genius 4015 points

Duke-san,

Thank you for your prompt reply.

With regard to first inquiry, we can send you a schematic, but this is a customer proprietary data.

Please let me communicate with you directly via e-mail in order to have further proceed.

Best regards,

0 Kevin Duke over 10 years ago in reply to Atsushi Okui

TI__Mastermind 46290 points

Okui-san,

I have sent you an email to the address you registered on the E2E Community. We can continue this discussion there.

0 Atsushi Okui over 10 years ago in reply to Kevin Duke

Genius 4015 points

Duke-san,

Hello, thank you very much for your e-mailing to me.

As this reply, I sent customer's schematic.

Please let me know whether you could receive this.

We thank you once again for your information.

Best regards,

0 Kevin Duke over 10 years ago in reply to Atsushi Okui

TI__Mastermind 46290 points

Okui-san,

I am away from my office on business travel and haven't had a chance to look at the schematic and give it it's due diligence yet. I will update you when I get the chance.

0 Eugenio Mejia over 10 years ago

TI__Genius 10615 points

This thread is being attended offline for customer privacy.

0 Eugenio Mejia over 10 years ago

TI__Genius 10615 points

Okui-san,

I sent you the DAC8831EVM with an OPA172 for you to test the chip performance.

Let me know if you need anything else from me.

0 Atsushi Okui over 10 years ago in reply to Eugenio Mejia

Genius 4015 points

Meja-san,

Thank you very much indeed for your arrangement to send DAC8831EVM with OPA172.

We are looking forward to receiving that.

Best regards,

Because of the Thanksgiving holiday in the U.S., TI E2E™ design support forum responses may be delayed from November 25 through December 2. Thank you for your patience.

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Inquiries regarding DAC8831