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DS90LVRA2-Q1:

Michael Bins
Prodigy 10 points
Part Number: DS90LVRA2-Q1

Tool/software:

1. The Absolute Maximum Ratings of DS90LVRA2-Q1 allow for a VCC of 0V to 4V. I understand that if I set VCC to a voltage not within the range of one of the three modes lists (1.8V, 2.5V, 3.3V) that the output specifications listed will then not apply. But would there be any other reason not to do this? In my application I have a supply of 3.0V+/-10% and the output level is not critical. But I need to know that the device will otherwise function as expected.

2. The input thresholds are specified for VCC from 1.62V to 3.6V, which appears okay. It mentions Vib from -4V to 5V. What does Vib refer to?

  • 0
    TI__Genius 15321 points

    Hi Michael,

    1. The ABS Max specifications in the datasheet are the defined limitations that if exceed, the device may be permanently damaged. For the intended design, it is recommended to use the device under the recommended operating conditions. A supply voltage that you have mentioned above would fit within the recommended operating conditions of 3.0V (min) to 3.3V (nominal)

    2. I believe this parameter is referring to the extended common-mode range of the device. This device offers an extended common-mode input range ideal for applications expecting large ground shifts between the driver's ground reference and receiver's ground reference. Pg. 9 of the datasheet mentions that "the DS90LVRA2-Q1 differential line receiver is capable of detecting signals as low as 100mV over a common-mode range of −4V to 5V (VCC at 3.3V). The common voltage range is related to the LVDS driver offset voltage, which is typically +1.2V." 

    Thank you, 

    Amy

  • 0 in reply to Amy
    Prodigy 10 points

    Hi Amy,

    Thanks for the response. Regarding question 1, I see now that my supply is actually 3.0V +/-3% (2.91V to 3.09V). So the range from 2.91V to 3.0V would not fall within the recommended range. I understand that this means the output level is not absolutely specified, but in my application the output level is not critical since it won't be used to drive a logic input. So if the supply voltage is 2.91V, my question is whether there is any reason to expect that the output level would fall below the specified minimum for a 2.5V supply and rise above the specified maximum for a 3.3V supply? For example, might the output be disabled or become unstable with a 2.91V supply voltage? Any other related thoughts on this would be helpful. Thanks.

  • +1 in reply to Michael Bins
    TI__Genius 15321 points

    Hi Michael,

    Thank you for your follow up question. Since you are on the edge of the minimum supply requirements for 3.3V mode, the device performance may or may not be impacted as it relates to 3.3V mode. A supply voltage of 2.91V falls right in between the 2.5V mode max (2.75V) and the 3.3V mode min (3.0V). The main idea here is that the exact datasheet parameters cannot be guaranteed if the device is operating in this case, in between, the recommended operating conditions. If you prefer to be guaranteed that the datasheet metrics will be met for either one of these modes (2.5V or 3.3V), it would be recommended to operate within the boundaries of the min/nominal/max voltage supply conditions for either mode. 

    Hope this helps clarify, please let me know if you have any other questions. 

    Warm regards, Amy