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DAC7718: Output current ratings

Caglar Cihan
Expert 6235 points
Part Number: DAC7718
Other Parts Discussed in Thread: DAC7716

Dear Team,

On the datasheet of DAC7718, AIDD is given as 7mA(max) in “ELECTRICAL CHARACTERISTICS: Single-Supply (continued)” section. However, Figure 84 max source current looks like to be around 9mA. Could you please take a look and advise which one is relevant?

There are some more questions as follows:

- What is the max current at Vout=12V condition?

- What is the typical efficiency of the device?

- Max short current is given as +/-8mA on the datasheet. The note(5) states as “(5) When the output current is greater than the specification, the current is clamped at the specified maximum value.” What is the max time that the part can be hold at short condition?

- DAC7716 could also be an option, but load current graph and measurements for Unipolar operation is not given on the datasheet. Is it possible to get this information.

Best Regards,

Caglar

  • 0
    TI__Genius 11750 points
    Howdy Caglar,

    After reviewing the DAC7718 datasheet, I would suggest that the device only drive loads that require less than 8mA of current, as the datasheet additionally states that a typical load current of +/-3mA was used in generating the criteria expressed in the datasheet. Anything above 8mA may start to trip the short circuit protection circuitry, which may start to collapse the voltage seen at Vout. Figure 84 does show some voltage collapse at 9mA, however it appears to be very linear until it abruptly rolls-off at ~9.5mA. The datasheet probably safeguards to an extent, by adding margin in establishing the 8mA parameter.

    Another important graph to look into is the "Delta Output voltage vs Source and Sink Currents" graph, which is shown in Figure 37 of the DS. This graph does show how increased sink/source currents will impact the programmed output voltage.
    This graph is also shown for the DAC7716 device, in Figure 28 of the DAC7716 datasheet. You will notice that the delta output voltage is much lower than the DAC7718 device. The DAC7716 datasheet also displays a typical short-circuit current value of 10mA.

    Best Regards,
    Matt