LM2940C: LM2940IMP-5.0/NOPB

Hi Arnaud,

We do not have this data. If you would like I can order some devices to measure it, but it won't be until late next week that they arrive here if I order them today. If that's what you would like then please confirm it and I'll order the devices.

Regards,

Nick

Hi,

Yes, it will ne nice if you can order and test if you do not mind.

Is there a reason why the delay is not specified?

Thanks a lot,

Arnaud

Hi Arnaud, 

Sounds good, I'll order the parts and measure it when they arrive. In the meantime, can you tell me how you would like me to specify the delay? Does 1, 2, or 3 from the diagram below describe the delay you would like measured?

This device was released in 2000 when the timing characteristics of LDOs (and really a lot of other specs) were not well-specified (in my understanding - I was not an engineer in 2000). Most of our modern devices have timing information, at least in the form of a transient waveform showing the startup or sometimes an actual EC spec.

Regards,

Nick

Hi Nick,

Yes, if you can do all 3 measurements, it will be perfect. At what load are you going to test (0A, 50%, 100%)?

Thanks a lot for your help,

Arnaud

Hi Arnaud,

Sounds good. Is there a load to start up into that would be of interest to you? If not I would normally use some "small" load, say 10% of the rated load current (100mA for this device), but if you expect to start up into a heavier load then I can use that. The startup is usually not affected too much when the load cap is not very large or the load current is not large, but can be affected if either is large, in particular the case where the device gets to current limit during startup. Also, the electrical specifications were characterized with a 22uF output cap (probably solid tantalum); do you know what you would use if you went with this device? Ceramic caps can't work on their own for this device since there's a minimum ESR requirement of 100mΩ.

Regards,

Nick

10% is fine. 

Thanks,

Arnaud

Hi Arnaud,

Got it. Does solid tantalum work for the cap?

Thanks,
Nick

Yes, should be fine.

Regards,

Sounds good, will update when I finish testing. 

Hi,

Any updates on the test? Or do you have an estimate when we will be able to get some data?

Thanks a lot,

Arnaud

Hi Arnaud,

My apologies, this post got lost and I forgot about it. I checked on it looks like I never got the devices ordered. I just ordered them so I will have to wait until they get in to test. They should be here mid-next week. Very sorry for the inconvenience.

Regards,

Nick

Hi, Any update on the test? Thanks

Hi Arnaud,

We should have an update for you tomorrow. Sorry again for the delay. 

Regards,

Nick

Hi Arnaud,

I'm very sorry again for the delay. Our engineer that can take the measurement has something urgent that he's working on so he will try having it done by Friday.

Regards,

Nickw