LM321: More current?

Mike Trantham

Part Number: LM321
Other Parts Discussed in Thread: TLV9301, LM7705

I'm using the MFX version with a 12V power supply to make a 0-10V signal. It works very well with a high-impedance load, but sometimes I need to drive a load with as little as 500 ohms. Is there a different part that I should be using? I really want to be able to drive with a single-ended power supply and go from 0 to 10V.

over 1 year ago

+1 Gerasimos Madalvanos over 1 year ago

TI__Mastermind 29186 points

Hey Mike,

10V/500Ohms is 20mA, which is close to the short circuit current limit. TLV9301 gives you a lot more headroom at a good price point, the short circuit current limit is 60mA, and you get rail to rail output.

Best,
Jerry

0 Mike Trantham over 1 year ago in reply to Gerasimos Madalvanos

Prodigy 10 points

Thanks! It even has the same footprint.

0 Gerasimos Madalvanos over 1 year ago in reply to Mike Trantham

TI__Mastermind 29186 points

Hey Mike,

Happy to help! We have a whole bunch of devices in that footprint, most of them are P2P, but make sure you look out for a U in the part name if it's single channel (this is mostly for our lower voltage devices). Those are to accomodate the uncommon or unusual pinouts that are supposed to match P2P with some legacy devices.

You can even filter by spec with the parametric table (linked below). This is usually the fastest way I find alternative parts!

https://www.ti.com/amplifier-circuit/op-amps/general-purpose/products.html

Best,
Jerry

0 kai klaas69 over 1 year ago

Guru 140200 points

Hi Mike,

keep in mind that the output of OPAmp may not go all the way down to 0V with a heavy load of 500 Ohm, if the OPAmp is supplied with a +12V single supply. You may eventually need a small negative supply voltage. The LM7705 could be an option.

Kai

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LM321: More current?