Electronics > Beginners

Is op amp supply current on datasheet per channel?

(1/1)

Bootalito:
I'm searching for an optimized 4 channel op amp to drive a 4 parallel mosfets for an electronic load.  I'm able to achieve ~0.02A/uSwith an AD8630 by using a 330R resistor to gate or about 15mA per channel.  The AD8630 has an output short circuit current of 50mA, so I'm a bit overspec, but its stable.  I need more power!

The AD8534 says it has a "250mA Output".  Then I realized I didn't actually understand if the datasheet specification for "Output Current Limit", "Output Short Circuit Limit", etc, was for the entire device or per channel.  I figured these specs were for the entire device regardless of if its a single or quad channel amp.  But I really don't know!

I'm using the same mosfets as the Rigol Electronic load, and it has a claimed spec of 5A/uS with 12 Fets.  I think it has a 3.3R resistor and when you do the math with the gate charge its in the ball park of 5A/us.  How does one deliver 4Amps to a mosfet gate in the linear region in a controlled manner?  I mean you can use a gate driver, but that's just for slamming the gate open and shut. 

Nerull:
https://www.analog.com/media/en/technical-documentation/data-sheets/ad8531_8532_8534.pdf

Page 11 has section on maximum power

Bootalito:
Thanks

In an electronic load application the application of power is so brief as to be non-consequential though.  Although in that section it says the minimum resistor one should place on the output is 20R.  5V / 20R = 250mA.  But what if I'm using a quad package?  Does this mean I can put 20R resistors on each output?  Meaning that the entire package will be driving 1A of power for about 50us

Navigation

[0] Message Index

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod