| 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 |
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