OK, enough showing off; I have a real question now.
All of these boards have STW34NB20 for the output devices. On the RB-TDA2500 I would like to replace these with STW75NF20 to power low impedance loads in a car amp with +/-45v rails.
My questions is; is there any way to guess if the dead time will need to be adjusted? Will it need to increase or decrease? I don't own a scope nor do I have access to one so I have no way to check shoot through.
STW34NB20
Rds(on): 0.062 OHM
Total Gate Charge: 60nC
STW75NF20
Rds(on): 0.028 OHM
Total Gate Charge: 84nC
All of these boards have STW34NB20 for the output devices. On the RB-TDA2500 I would like to replace these with STW75NF20 to power low impedance loads in a car amp with +/-45v rails.
My questions is; is there any way to guess if the dead time will need to be adjusted? Will it need to increase or decrease? I don't own a scope nor do I have access to one so I have no way to check shoot through.
STW34NB20
Rds(on): 0.062 OHM
Total Gate Charge: 60nC
STW75NF20
Rds(on): 0.028 OHM
Total Gate Charge: 84nC
Hi
You are not looking for right specs
You should be looking at Qrr and Trr, should be much smaller, and Qg so you won't burn chip
You should be looking at irfp4227 or FDP series, so look at zip, you might find some that you can get
You are not looking for right specs
You should be looking at Qrr and Trr, should be much smaller, and Qg so you won't burn chip
You should be looking at irfp4227 or FDP series, so look at zip, you might find some that you can get
Thanks Luka.
I can't source any IRFP4227 and I can't view the xls file right now.
Are you sure the STW75NF20 will be that much harder to drive? The specs you mentioned aren't that different between the two. I can get these relatively cheap, so I would like to use them if possible.
STW34NB20
Tj = 150 °C
Trr - 290ns
Qrr - 2.7uC
Irrm - 18.5
STW75NF20
Tj = 150 °C
Trr - 267ns
Qrr - 3uC
Irrm - 22A
I can't source any IRFP4227 and I can't view the xls file right now.
Are you sure the STW75NF20 will be that much harder to drive? The specs you mentioned aren't that different between the two. I can get these relatively cheap, so I would like to use them if possible.
STW34NB20
Tj = 150 °C
Trr - 290ns
Qrr - 2.7uC
Irrm - 18.5
STW75NF20
Tj = 150 °C
Trr - 267ns
Qrr - 3uC
Irrm - 22A
Hi
It is worse then original, anyway I don't know why tripath said/used fets old like that. Do not use other one, it is just bad, thats why it is cheap.
Use something like
FDP2552
Qrr max - 242n
Trr max - 90n
Qg - <51n
RsdOn - <36m
Id - 37
Vds - 150v
or
FDP2572
Qrr max - 169n
Trr max - 74n
Qg - <34n
RsdOn - <54m
Id - 29
Vds - 150v
For other try to view xls
It is worse then original, anyway I don't know why tripath said/used fets old like that. Do not use other one, it is just bad, thats why it is cheap.
Use something like
FDP2552
Qrr max - 242n
Trr max - 90n
Qg - <51n
RsdOn - <36m
Id - 37
Vds - 150v
or
FDP2572
Qrr max - 169n
Trr max - 74n
Qg - <34n
RsdOn - <54m
Id - 29
Vds - 150v
For other try to view xls
You know much more than I do, so I will take your word for it and try to find something else. 😉
I found a nifty online excel viewer at http://sheet.zoho.com/excelviewer.do
OK, I can get FDP2532 and it can do 79A. Do you see any problems in using this one? Will any components need to be modified other than maybe dead time?
http://www.fairchildsemi.com/ds/FD/FDP2532.pdf
I found a nifty online excel viewer at http://sheet.zoho.com/excelviewer.do
OK, I can get FDP2532 and it can do 79A. Do you see any problems in using this one? Will any components need to be modified other than maybe dead time?
http://www.fairchildsemi.com/ds/FD/FDP2532.pdf
Hi
This one is not it the top spot, but it is not far from it, so yes this will be ok
Dead time...well I have it on my amp2 on max, so see how much that is any use something like that....but as far as I can see now you won't need change dead time, because this fets are way faster then originals, so if you will use it for sub, have high dead time anyway because you will gain on llower heat produced
This one is not it the top spot, but it is not far from it, so yes this will be ok
Dead time...well I have it on my amp2 on max, so see how much that is any use something like that....but as far as I can see now you won't need change dead time, because this fets are way faster then originals, so if you will use it for sub, have high dead time anyway because you will gain on llower heat produced
Luka,
I spent some time looking at the different MOSFETS in the excel file. The FDP3651U is cheap and available and has better specs (i think) than the FDP2532.
My questions is, will it survive +/-45v rails since it is only rated at 100v?
Thanks.😀
I spent some time looking at the different MOSFETS in the excel file. The FDP3651U is cheap and available and has better specs (i think) than the FDP2532.
My questions is, will it survive +/-45v rails since it is only rated at 100v?
Thanks.😀
Hi
Apart from a bit high input C it is good one, and it will work ok, 100V is miminum that must still hold, so if you have fails that won't go higher then +/-50v, like limited by suppressor diodes you are good to go
Apart from a bit high input C it is good one, and it will work ok, 100V is miminum that must still hold, so if you have fails that won't go higher then +/-50v, like limited by suppressor diodes you are good to go
Hi
Mad high 😀, no what I think is you would need to take it slow, watch rails with scope, to see if they rise, but in BTL mode you won't have that, so I think you are still good to go. I am not jokig do it for real
Mad high 😀, no what I think is you would need to take it slow, watch rails with scope, to see if they rise, but in BTL mode you won't have that, so I think you are still good to go. I am not jokig do it for real
luka said:I am not jokig do it for real
I plan on it. I mean what do I have to lose besides an expensive impossbile to find eval board.😀
I know the power supply can handle the load. The class AB amp it came from used to power a 1R BTL all day with no problems.
Sorry off topic, but theAnonymous1, those aluminum cone woofers you got there, where did you get them? I've been looking for something like that for a while now... Unless they were pre-built, then I guess I'm SOL
theAnonymous1 said:
Those drivers are "all show, no go" so to speak.
I built those speakers a long time ago before I really knew anything about anything. The aluminum cone drivers are just some garbage dvc car audio drivers I found at wal-mart. They were painted red but I stripped the paint off them.😱
I just keep the 3-ways around for testing because i'm not afraid of frying them.
I built those speakers a long time ago before I really knew anything about anything. The aluminum cone drivers are just some garbage dvc car audio drivers I found at wal-mart. They were painted red but I stripped the paint off them.😱
I just keep the 3-ways around for testing because i'm not afraid of frying them.
I just finished my "high-current" mods of the RB-TDA2500. The output inductors are 1.75" O.D. with 12 gauge wire, the over-voltage was reduced to 50v, the output devices changed to FDP3651U 100v 80A 0.015ohm MOSFETs, and over-current set to 30A(for now).
An externally hosted image should be here but it was not working when we last tested it.
It's been playing for around an hour off my current limited supply (+/-45v @ 500ma). The only high power supply I have is the car SMPS it will be used with, but that's on the bench getting worked on.
It's playing as loud as it can off the low power supply and everything seems to be running cool. I plan to add a heatsink to the bottom of the IC when I get the time.
It's playing as loud as it can off the low power supply and everything seems to be running cool. I plan to add a heatsink to the bottom of the IC when I get the time.
Well, my TDA2500 IC died today, in what can only be described as a moment of total stupidity. I've been very careful with everything I've done so far, making sure to double check everything.
In a lapse common sense I had put the IC in it's socket without checking to make sure it was seated correctly. It wasn't; all the pins where over one position and I powered it up like this.
Stupid..... stupid..... stupid.😱
Man, those RA-2500 replacements aren't cheap either.🙁
In a lapse common sense I had put the IC in it's socket without checking to make sure it was seated correctly. It wasn't; all the pins where over one position and I powered it up like this.
Stupid..... stupid..... stupid.😱
Man, those RA-2500 replacements aren't cheap either.🙁
Here is a pic of the inner workings of the TDA2500. The whole circuit seems to based around a Tripath "TZ0105" IC. The two epoxy coated devices look like they are the drive transistors for the output FETs.
An externally hosted image should be here but it was not working when we last tested it.
luka said:Hi
😱 andand
and so on...
Indeed.🙁
Actually, after grinding the the epoxy away those other devices look like they might be another Tripath IC. There are too many traces going to it for it to be a transistor.
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