OPA541 w/ or w/o thermal protection?

JojoD818 · 2nd January 2004, 01:02 AM

Hi everyone,

I have read the OPA541's datasheet and it says nothing about any thermal protection, can this be true or is it just my eyes? An expensive chipamp without thermal protection, only over-current protection.

Or can it be that the over current protection also governs the thermal protection scheme?

Oh please shed some light unto this matter.

Happy New Year,
JojoD

JojoD818 · 2nd January 2004, 10:00 AM

Anyone have an idea on this?

Mad_K · 2nd January 2004, 10:08 AM

I don't think it has a thermal protection since it is not mentioned in the datasheet. I don't use the current-limit R either... No protection for me thank you

JojoD818 · 2nd January 2004, 03:31 PM

Mad_K,

I see you agree that it is really not mentioned in the datasheet, hence it has no protection whatsoever. Now isn't that dangerous? A fault can cook our speakers, yes?

JojoD

JOE DIRT® · 2nd January 2004, 04:17 PM

JoJo, thermal protection regarding the opa 541 is acheived with the Imax protection hence when the chip exceeds it SOA, current demand will increase and be limited to the value set by the reference rersistor.So in essence it is a good design rule to utilise a current limiting resistor so the output will clamp (crowbar) the output so that the load and chip are protected.

DIRT®

JojoD818 · 2nd January 2004, 04:36 PM

Okidoki, so the current limiting is not a bad idea afterall. So in other words, the OPA541 can be used safely since it has the necessary precautionary measures when used with varying speaker loads.

Thanks,
JojoD

JOE DIRT® · 2nd January 2004, 04:52 PM

You are on the right track now

Easyamp · 2nd January 2004, 06:02 PM

I use a thermal pcb switch from airpax to either switch on a fan or trip a relay cutting the supply but this is only necceary for an extra amount of protection for opa541 as the current limit function will work under normal conditions but.

These little guys are cheap and very accurate and can be used in just about anything (I don't work for them Honest).

I have only used these for a few months so I cannot comment on reliability.

Mad_K · 2nd January 2004, 07:29 PM

Protection, smotection

Joe nailed it!

Matttcattt · 2nd January 2004, 08:06 PM

Quote:

Originally posted by Easyamp
I use a thermal pcb switch from airpax to either switch on a fan or trip a relay cutting the supply but this is only necceary for an extra amount of protection for opa541 as the current limit function will work under normal conditions but.

These little guys are cheap and very accurate and can be used in just about anything (I don't work for them Honest).

I have only used these for a few months so I cannot comment on reliability.

what are they? like a teperature controlled switch? whats the part number?

2nd January 2004, 01:02 AM	#1
JojoD818 diyAudio Moderator Join Date: Mar 2003 Location: diyAudio Special Operations Center	OPA541 w/ or w/o thermal protection? Hi everyone, I have read the OPA541's datasheet and it says nothing about any thermal protection, can this be true or is it just my eyes? An expensive chipamp without thermal protection, only over-current protection. Or can it be that the over current protection also governs the thermal protection scheme? Oh please shed some light unto this matter. Happy New Year, JojoD

2nd January 2004, 10:08 AM	#3
Mad_K diyAudio Member Join Date: Sep 2002 Location: Norway	I don't think it has a thermal protection since it is not mentioned in the datasheet. I don't use the current-limit R either... No protection for me thank you __________________ Mads K

2nd January 2004, 07:29 PM	#9
Mad_K diyAudio Member Join Date: Sep 2002 Location: Norway	Protection, smotection Joe nailed it! __________________ Mads K

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2nd January 2004, 10:00 AM	#2
JojoD818 diyAudio Moderator Join Date: Mar 2003 Location: diyAudio Special Operations Center	Anyone have an idea on this?

2nd January 2004, 03:31 PM	#4
JojoD818 diyAudio Moderator Join Date: Mar 2003 Location: diyAudio Special Operations Center	Mad_K, I see you agree that it is really not mentioned in the datasheet, hence it has no protection whatsoever. Now isn't that dangerous? A fault can cook our speakers, yes? JojoD

2nd January 2004, 04:17 PM	#5
JOE DIRT® diyAudio Member Join Date: Apr 2003 Location: Brantford, ON	JoJo, thermal protection regarding the opa 541 is acheived with the Imax protection hence when the chip exceeds it SOA, current demand will increase and be limited to the value set by the reference rersistor.So in essence it is a good design rule to utilise a current limiting resistor so the output will clamp (crowbar) the output so that the load and chip are protected. DIRT®

2nd January 2004, 04:36 PM	#6
JojoD818 diyAudio Moderator Join Date: Mar 2003 Location: diyAudio Special Operations Center	Okidoki, so the current limiting is not a bad idea afterall. So in other words, the OPA541 can be used safely since it has the necessary precautionary measures when used with varying speaker loads. Thanks, JojoD

2nd January 2004, 04:52 PM	#7
JOE DIRT® diyAudio Member Join Date: Apr 2003 Location: Brantford, ON	You are on the right track now

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