LME49810 - a new cousin for LM4702

[jackinnj]

Originally posted by Russ White
I am not sure I can find a good reason to prefer the LM4702 for any application..... Honestly.

It's two channels, so less real estate consumption.

[Russ White]

Originally posted by jackinnj


It's two channels, so less real estate consumption.

Sure, but that does not carry much weight...

Also to get the same capability you would need to add more parts to the LM4702 (clamp and drivers etc) which would probably take more space than two 49810s.

Not saying the 4702 is bad, but I think the 49810 is better (on paper as I still have to hear it) in my book.

Cheers!
Russ

[jackinnj]

for DIY it's a small consideration -- for a manufacturer of high end products heeding National's guidelines there's the need for localized decoupling and storage at the power pins of either chip --

a hint for both chips -- mount the decoupling caps on the underside of the PCB -- and if possible use polypropylene devices -- you want the legs on the decoupling caps to the as short as possible.

[Nordic]

Despite the extra cost and size, I do still prefer mono chips to their stereo competition... i.e. i'd rather use opa134 than 2134....

As seen from a sonic quality viewpoint... not to mention some of the other distortion mechanics involved in a shared chip...

[Russ White]

Originally posted by jackinnj
for DIY it's a small consideration -- for a manufacturer of high end products heeding National's guidelines there's the need for localized decoupling and storage at the power pins of either chip --

Hmm I thought this was DIY aduio....

But just to play along, I am sure other factors important to commercial applications are:

- Overdrive stability
- Flexible drive capability
- Wider range of power device choices

I don't see how it would be any more difficult to produce a great stereo amp with the mono chip. In fact it would probably be less expensive to use it if you matched feature for feature.

It may be an apples/oranges comparison.

The 4702 simply does not have the same capabilities on its own. Thats the main point.

[ozonek]

I am thinking about the difference between LM4702 and LME49810. Is there possibility that these two chips are made using same die and configured (enable/ disable certain circuits such as Baker clamp) according to their own specs. For memory devices, it is common practice, not sure if it is the same in the analog world.

Has anyone opened these two chips to see the difference of the die itself?

[glennb]

Originally posted by ozonek
I am thinking about the difference between LM4702 and LME49810. Is there possibility that these two chips are made using same die and configured (enable/ disable certain circuits such as Baker clamp) according to their own specs. For memory devices, it is common practice, not sure if it is the same in the analog world.

Has anyone opened these two chips to see the difference of the die itself?

The chip design of the 49810 is probably based on half a 4702, with improved slew rate, added baker clamp, clip flag, higher current output transistors. Neither are listed on http://www.national.com/packaging/parts/DIE.html

I have yet to have the misfortune of letting the blue smoke out of a 4702 or 49810, but if I do, it would be worth trying to expose the die.

[minicar]

Originally posted by glennb


The chip design of the 49810 is probably based on half a 4702, with improved slew rate, added baker clamp, clip flag, higher current output transistors. Neither are listed on http://www.national.com/packaging/parts/DIE.html

I have yet to have the misfortune of letting the blue smoke out of a 4702 or 49810, but if I do, it would be worth trying to expose the die.

I think you are right. It is base on the 4702 but not the same die. Their slew rate and some other spec are different, should be another design.

[Russ White]

All you have to do is ask....

I called National. It is a different die. It is in fact a significantly different bias scheme. Though National will not give away the farm.

According to the nice gentleman I spoke with there are more new devices on the way as well... Could it be a new dual part coming based on the 49810? Hmmmmm that would be sweet.

Cheers!
Russ

[Eva]

I really miss a current limiting feature in those chips