LME49810 - a new cousin for LM4702

Jump to Latest
#282
ionomolo said:
I guess i will have to do a board for this thing... I'm quite young and also frustrated doing P2P, 4 LME49810 went to garbage.

Now trying to understand how to create an orcad layout footprint
Click to expand...

I have built so many prototypes now and I can't imagine doing it without PCBs anymore. There is just not enough time.

You might wish to try DipTrace. I have no financial interest, it is just a fine tool. They have a free version which should suit your needs needs and it is significantly easier to use than Orcad or Eagle. If you need the LME49810 part library and pattern for DipTrace let me know and I will post it.

Cheers!
Russ
 
#283
Thanks, but my problem isn't not having the library, but rather learning to use a new tool. I will post mine (Orcad Layout) once i finish it. My idea is to do a board having some optional resistors and capacitors to support both mosfet and bjt.

What i've also found is that drilling pcb's is also very time-consuming.

How does your IRPF prototype sound? Which gate resistor did you use? did you use any GS/GG capacitor?
 
#287
Yeah, mine worked for two minutes, too short to enjoy it, too much to give up doing another.

Now I'm working in an "introductory level" board that i hope to finish on christmas holydays, the main aim of this board is to be easy-etchable (read single layer) for those of we who have lost weeks with this ic.

Must also tell that my long-term project is to do a bridged monoblock board having 100 v/usec slew rate and current flowing directly from V+ to V- without altering ground (of course lme49810 powered from a separate supply) and the soha amplifier from the headphone community as input stage of the integrated amplifier, but i don't expect to have this done in 2008.

Somebody can tell a success story to aim us?
 
#289
I'll tell my symptoms: GND, MUTE, CLIPFLAG and Vin+ are shorted internally and output transistors show near zero EC resistance (are blown). I think the LME blown and then did the output transistors. The lme was running without heatsink from 30V rails and was barely warm. I guess it was a short or something that made everything blow, but with such a thiny pins it is almost impossible to get that working without board.
 
#290
wow Russ... diptrace is really wonderful. I did not expect that switching from an application i was using for three years would save me time, but i've done my 7.1 gainclone amplifier board in less than one hour (including the time spent in downloading and installing diptrace)!
 
#291
JPV said:


Could you tell us if it is the LME49810 that is dead or the output transistors or both?

I am interested in your experience good ou bad with this chip

Thanks
Click to expand...

I took the transistors out -- and set it up with 10 ohm resistors on the source and sink pins -- to Rf and the output sense pins -- and tied the bias pins together per the test setup -- the device swings from rail to rail in a square wave without a 2 second cycle (1/2 Hz).

It is heat sinked with a 1" square piece of copper -- this is the first LME49810 I've blown up.
 
#292
ionomolo said:
wow Russ... diptrace is really wonderful. I did not expect that switching from an application i was using for three years would save me time, but i've done my 7.1 gainclone amplifier board in less than one hour (including the time spent in downloading and installing diptrace)!
Click to expand...


Yes it is a breath of fresh air after using Eagle for quite a while.

I think its a great tool for this hobby. The free version is very usable (no board size limit) and the prices are very reasonable for the more full featured versions, unlike Eagle.

You just have to plug a product as good as that one, and as DIY friendly.

Cheers!
Russ
 
#297
This is a rather embarrassing setup -- a pair of LME49810 boards in a Crown DC150. they are at a skew angle as the boards were set up to drive the Sanken output transistors but I couldn't get the LME49810 to work with them.

An externally hosted image should be here but it was not working when we last tested it.


The week after Christmas we are going to have a shootout -- LM4702 driving lateral MOSFETs, LME49810 driving diode-incorporated bipolars (with a driver stage_ and LME49810 driving Darlingtons -- all in the Crown boxes.
 
#298
jackinnj said:
This is a rather embarrassing setup -- a pair of LME49810 boards in a Crown DC150. they are at a skew angle as the boards were set up to drive the Sanken output transistors but I couldn't get the LME49810 to work with them.

An externally hosted image should be here but it was not working when we last tested it.


The week after Christmas we are going to have a shootout -- LM4702 driving lateral MOSFETs, LME49810 driving diode-incorporated bipolars (with a driver stage_ and LME49810 driving Darlingtons -- all in the Crown boxes.
Click to expand...

Very interesting experiment. I am waiting for your results

Why could you not use the Sanken one's?

Jean-Pierre
 
#299
JPV said:
Very interesting experiment. I am waiting for your results

Why could you not use the Sanken one's?

Jean-Pierre
Click to expand...
I used the first Sankens, the SAP16's with the LM4702 but the results were not that good as the devices couldn't be biased enough to get the THD% under 0.01% -- I think that the Elektor article pointed this out.

With the newer Sankens (STD03) the output kept slamming against the rails when I tried to drive them with the LME49810.

The new Sankens seem to just cut out the incorporated emitter resistor -- this resistor was (I guess) prone to failure.
 
#300
SpittinLLama said:
You could wait a few more weeks, the FET version of the drivers will be out soon. It doesn't have a Baker clamp or a clip indicator but it does have the rest and it can bias even higher. I have worked with the LME49810 and the FETs you list, along with others, and it works fine. As you have pointed out, the LM4702 can't get enough bias voltage for these particular FETs.

-SL
Click to expand...


http://www.national.com/pf/LM/LME49811.html

The new version of the LME49810 is out , atleast in datasheet. Some interesting reading over christmas?
 
You must log in or register to reply here.
Top Bottom