# What is the maximum output current for this op-amp (OPA4227)?

Usually in an op-amp datasheet I see that the op-amp output current's min, max, and typical values are stated.

But for the OPA4227 op-amp one finds two sections about currents:

Signal input terminals with max. 20 mA and Short-Circuit Current with ±45 mA.

Being confused with terminology, which one is the maximum output current this op-amp can source?

• It is an opamp, not a power amp. Its specs show good results with a 10k ohms load or a 3.5V loss with a 600 ohms load. 11.5V peak/500 ohms= 19.2mA. Don't use a load that is less than 600 ohms. Jan 29, 2023 at 22:46
• I can't answer for sure, but it looks like a 20 mA continuous short circuit to GND and +/-45 mA short circuit maximum. It may be internally limited. Jan 29, 2023 at 22:50

It is specified to deliver minimum +/-11.5 V into a 600Ω load with +/-15V supplies, so if you have +/-15V supplies you can count on +/-19.1mA, which is well within the typical short-circuit current of +/-45mA. That applies over the entire temperature range.

If your supplies are less than +/-15V, say +/-V you may have similar available current in practice (see the typical curves), but only +/- (V - 3.5)/600 is guaranteed.

• Oh so if I use 5V single supply, will the guaranteed output current be only (5- 3.5)/600 = 2.5mA? I was planning to drive a power transistor(TIP120) with this opmap(with 5V single supply) but seems there's chance I exceed limits. Can there be an opmap which can source between max 10mA to 20mA even at 5V supply?(I also need DIP package for some reason)
– GNZ
Jan 29, 2023 at 23:16
• TIP120 is an NPN Darlington. If you're driving it as a follower the current from the op-amp will not be very limiting (2.5A out minimum for 2.5mA in) but you'll lose another 2.5V max (typical will be less) giving you zero output voltage worst-case with a 5V supply. You may want to pose another question with your complete proposed schematic and application requirements and remembering that product recommendations are not allowed, ask for which specifications to look for. Jan 29, 2023 at 23:26
• Ok sure I will open a new question and update you the link. I hope you can look into it.
– GNZ
Jan 29, 2023 at 23:34
• I opened a new question now. here: electronics.stackexchange.com/questions/652015/… It would be great to have your feedback.
– GNZ
Jan 30, 2023 at 0:23

Maybe you overlooked the headings on the tables.

The 20 mA are the maximum current allowed on the input terminals, for instance in an ESD situation or other overvoltage - it's the rating of the internal clamping diodes.

The output short circuit current is stated as 45 mA. How much current you can draw is more precisely show in the graph:

For a temperature you can calculate output resistance, or voltage depending on your load. Note the curves aren't equal for sinking and sourcing if the current is over 30 mA.

For instance, with 15 V supply the output resistance is around 50 Ω and this resistance defines by how much the output voltage is smaller compared with zero load.

• How do you read this plot(for finding max output current) for 5V single supply at 25C? Can you mark that point in color in your answer?
– GNZ
Jan 29, 2023 at 23:21
• At 2V above and below supply rails, you can get about 20 mA. This would be 1 volt P-P for a 5V supply. Jan 30, 2023 at 0:03
• What is the load for these curves?
– GNZ
Jan 30, 2023 at 1:58
• (PStechPaul thanks) @GNZit is not simple to explain in short. The plot is for 15 V dual supply. The load is not a parameter, it's the result. The more mA you draw, the lower the output voltage goes, especially at 5 V supply. Show your schematic please. If you need to drive nany mA another opamp (rail-to-rail output, high drive current) could fit better... Jan 30, 2023 at 6:22