TI AN-1850 circuit with lme49830 and 2sk1530

[mantabernd]

Hello!

I'm quite new in this forum and I think there's much knowledge so I'd like to ask a few questions about my new project.

I'd like to build a amp with the LME49830. First I thought about taking the IRFP9240/240 mosfets but now I got four pairs for 2SK1530 / 2SJ201 from a friend. The TI Application Note AN-1850 shows an amplifier which uses these mosfets. So has anybody biult this amplifier shown in the app. note? I heard about oscillation problems and a difficult ground routing. I would design a very similar pcb layout as shown in the app. note but not with smd, such with throug hole components.

There's also explained how to route the grounds to the star point, I think I have to be very carefully...

Can anybody give me some tips about this amp? How does it sound with the 2SK1530 / 2SJ201 mosfets? Would it be better to use the irfp ones?

Best regards.
B. Waechter from germany

 

[AndrewT]

do Ti/National actually list those devices as one of the 3 alternatives for that 830 chip?

Start by wiring up just one pair. But before you use them measure and match your devices and source resistors.

 

[mantabernd]

Hello Andrew

Thank you for your reply. Yes the 2sk1530 / 2sj201 are recommend by ti/national.

Ok I will only wird one pair first. What do you think is the best was to messure the fets? simply messuring the resistance between the pins? I ve never done this before...

What do you say about the shematic? Is it ok or would you change something?

best regards

 

[AndrewT]

for your first pair you do not need to measure anything.

It's when you get to the next stage (if your ever need more driving power) of paralleling output devices that you need to measure and match.
Go and read the Threads and the websites links that explain about matching source resistors and explain about matching output mosFETs.