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DAC7551-Q1: resistor is connected to the VREFL terminal

cafain
Mastermind 6365 points
Part Number: DAC7551-Q1

Hi,

When a resistor is connected to the VREFL terminal of the DAC7551-Q1, you want to check the effect of the VREFL(3) pin.

Since we want to output approximately 0.7V to Vout when Code= "0"
When a resistor is inserted and connected between the VREFL(3) pin and GND(6),
Is there a possibility of damaging the device?

For example, the VREFL terminal is damaged when the power is turned on or during normal operation?

※ Since the internal resistance accuracy is ±20%,
　I understand that it is not recommended to connect a resistor between the VREFL terminal and GND.

Best Regards

cafain

  • 0
    TI__Genius 14220 points
    Hi Cafain,

    I don't think connecting a resistor at VREFL would damage the device but this condition is never tested. As you mentioned, it is not recommended to use the device in this topology to generate an offset as equation 1 (page 12) will not hold good looking at Figure 27 of datasheet. The device requires a constant voltage at VREFL, which can be generated by your approach but it is better to use a zener diode or a low-cost shunt to generate this voltage if there are system level constraints.

    If I remember correctly, you have been asking similar questions in the past, could you please let us know your exact constraints so that we can suggest you right options. We will be able to provide better support that way. If you want to share the details with confidentiality, we can take the discussion over mail. If you are ok, you can add me as a friend and I will share my email over a private message. We can then switch further discussion to email.

    Regards,
    Uttam Sahu
    Applications Engineer, Precision DACs
  • 0 in reply to Uttam Sahu
    Mastermind 6365 points

    Hi Uttam-san

    I appreciate your kind response.
    As a result of trouble occurring now, as a result of carrying out the internal analysis,
    　it was confirmed that the VREFL terminal wire was disconnected inside the device.
    (It is unclear whether trouble occurred due to aging stress)

    If there is further progress, we will consult with your personal e-mail address,
    　but now we will conduct the survey first.

    best regards

    cafain

  • 0 in reply to cafain
    TI__Genius 14220 points
    Hi Cafain-san,

    Please provide the detailed information regarding your experiments and analysis. We can take this over mail if required (you can send me your email-id over a private message using the friend request option). If you have an assigned FAE from TI please loop him/her in so that we can take the issue through the right process.

    Regards,
    Uttam