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LT6105 Input offset voltage

Category: Datasheet/Specs
Product Number: LT6105

LT6105 provides a Vos temp co and also a max Vos over temperature, but they do not correlate. Is the tempco somehow in addition to the max range ?

  • Hello JMC,

    If I understood the context your query correctly, you must be referring to these graphs here:

    To review, we have a given guaranteed Input Offset Voltage range of -1.6mV to 1.6 mV, and a temperature coefficient typically at 0.5uV/degreesC. The graphs above show the input offset voltage against the max temperature range, which is -40 to 125 degrees C.

    As per your query, most series do indeed not match the given coefficient of 0.5uV per degree Celsius of change, but it is also important to note that the given temperature coefficient in the datasheet is only the “typical” value, meaning it’s not constant and may vary for different samples.

    Let’s take the first graph, for example, where Vs+ is 12V; visually, each trial seems to have different temp co, yet still correlated to each other. If we compute for the offset (at 50 degrees C, for example), based on the provided temp co in the datasheet, we’ll have:

    (50℃-(-40℃))×0.5μV/℃=45μV

    That is approximately at the red dot marked below, which is visually not too far off from the mean of the samples.

    In the second graph, where Vs+ is 0, the temp co variance seems to be much larger, but it should also be noted that the values in the datasheet (unless otherwise stated) are recorded on test conditions where in Vs+ is equal to 12V.

    To answer your question, the temp co is not added on top of the given input offset voltage range. Rather, the temp co in the datasheet is a typical value based on multiple trials in a preset test condition and is, therefore, not absolute for all samples. An important takeaway, however, is that the temp co variations are minute (up to a few hundreds of microvolts) and the typical characteristic performance (both graphs) of the tested parts are still within the specified Input Offset Voltage range.

    Best Regards,
    Jeanne