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OPA2170: Output Voltage Swing vs Output Current with +-3.3V power supply

Part Number: OPA2170


With +-3.3V power supply, what is the output voltage swing with +-15mA and +-20mA load?


  • Edit: Post Removed and Reinstated

    Hello Di Wang1,

    Unfortunately, it is probably poor.  If you look at the "Short-Circuit Current" specification, the part is only rated to -20mA and +17mA at the output.  Note that by the time you've reached the output short circuit state, your output voltage is typically collapsing at that point.  It also should be pointed out that these are typical specs, meaning that not all parts will have the exact same threshold and some units may have slightly worse performance.

    Finally, the claw curve given in the datasheet and shown above is for the maximum supply.  For lower supply levels, such as +/-3.3V, there will be significantly less output swing merely by virtue of the supplies getting smaller.  Even if we assume that the curves for a +/-3.3V supply setup will be the same as the curves shown here, there is already about 1.5V of swing lost.  As you approach 15mA, I would expect tthe total output swing to approach zero.

    So, while your exact scenario is not explicitly explored in the datasheet, it is probably not a good idea to use this part to source that much current given what is in the datasheet.  Please let me know if you have any further questions or need help looking for a new part.