TCA0372 sub

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I forgot the part, ST or NXP or something. Anybody remember?


Re: TCA0372 sub
John Larkin wrote:
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ST L272.  Pretty similar except with a wimpy abs max supply rating.

Cheers

Phil Hobbs


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Dr Philip C D Hobbs
Principal Consultant
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Re: TCA0372 sub
On 21/01/2021 09:58, Phil Hobbs wrote:
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ST L2720 looks interesing also.


Re: TCA0372 sub
Chris Jones wrote:
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Might be the same die, but that P/N is long gone AFAICT.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs
Principal Consultant
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Re: TCA0372 sub
On 21/01/2021 15:29, Phil Hobbs wrote:
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No idea, I just saw the L2720 in stock when I was looking at L272, and  
noticed the higher bandwidth.

https://au.element14.com/stmicroelectronics/l2720w13tr/op-amp-dual-1-2mhz-2v-us-wsoic/dp/2806800?st=l272



Re: TCA0372 sub
Chris Jones wrote:
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Hmm, weird.  Digikey has none, and the first datasheet link I searched  
on came up with 'obsolete' scribbled all over it.  Probably just pilot  
error on my part.

Cheers

Phil Hobbs

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Dr Philip C D Hobbs
Principal Consultant
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Re: TCA0372 sub

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Octopart shows the STMicroelectronics L2720W13TR is available at Arrow  
with 4 in stock.

https://octopart.com/search?q=L2720&currency=USD&specs=0

The datasheet is clean.

https://datasheet.octopart.com/L2720W13TR-STMicroelectronics-datasheet-
62332974.pdf

At USD$0.619 ea, we should buy 4 and put it out of its misery.


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The best designs occur in the theta state. - sw

Re: TCA0372 sub
Steve Wilson wrote:
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Other places have more--see Octopart.  Digikey has a bunch on order.  
The other huge thing is that it's in the SO16-W package, and seems to be  
**pin-compatible with the TCA0372** (except faster and lower-voltage).  
That could come in handy.

Cheers

Phil Hobbs

--  
Dr Philip C D Hobbs
Principal Consultant
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Re: TCA0372 sub
On Thu, 21 Jan 2021 11:38:21 -0500, Phil Hobbs

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I use the TCA0372 to set Vhi and Vlo in my pulse generators.

https://www.dropbox.com/s/min68fawzv8okkg/Output_B.jpg?raw=1

but in this case, the max supply voltage spread is 31 volts.




--  

John Larkin      Highland Technology, Inc

The best designs are necessarily accidental.


  

Re: TCA0372 sub
snipped-for-privacy@highlandsniptechnology.com wrote:
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Yeah, not so compatible then.  Still, there are lots of times it would  
be a direct substitution, which puts one's mind at ease at least a little.

Of course you can probably make a million dollars' worth of pulsers with  
one reel of TCA0372s.

Cheers

Phil Hobbs


--  
Dr Philip C D Hobbs
Principal Consultant
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Re: TCA0372 sub
On Thu, 21 Jan 2021 12:13:06 -0500, Phil Hobbs

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$1.7 million.

I use them as power supply regulators, as a fan controller, and as a
relay driver too!

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I could tweak the supply voltages down a bit, if I had to. Reduce the
swing spec a tad.

It doesn't really need the 1 ohm resistors; sheer cowardice on my
part. But the ST sub may not be as stable.



--  

John Larkin      Highland Technology, Inc

The best designs are necessarily accidental.


  

Re: TCA0372 sub

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Hi John,

What is R303 in the schematics in reference, please.

H

Re: TCA0372 sub
wrote:


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That's a

RIEDON              PFC10-50RF1

or alternatly

CADDOCK             MP725-50.0-1%

Both are excellent wideband power resistors, even with the tabs hard
grounded.

The Riedon is a flat ceramic resistor that drops into a DPAK
footprint. The thermistor is hung on that. It all becomes a
sophisticated power overload computer.



--  

John Larkin      Highland Technology, Inc

The best designs are necessarily accidental.


  

Re: TCA0372 sub

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I see. I was just wondering why that metal tab is grounded. Thanks John.

H

Re: TCA0372 sub
wrote:


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Those resistors are rated for something insane like 25 watts. That
must assume serious heat sinking. Something more like 5 or 8 watts is
more reasonable on a PC board. I have vias to the layer 2 ground plane
and copper pours out to the board edges, where we can heat sink to the
box.




Re: TCA0372 sub

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how did you manage that ? For me that is impossible.

H

Re: TCA0372 sub
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I hacked some proto boards and tested some resistors for temp rise.
Advanced thermodynamics.

Here's one example.

http://www.highlandtechnology.com/DSS/J270DS.shtml

https://www.dropbox.com/s/mdrm7ow47mj3aug/J270_Bottom.jpg?raw=1

The 44 volt version can toast things if the user shorts the output and
cranks up the duty cycle.

The big gold strips get bolted to the case, which is the main cooling
path. I figure that resistor is good for 6 watts or so. R42 is the
shutdown thermistor.

I have some capacitance and TDR data around here somewhere, on those
resistors.





Re: TCA0372 sub

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Polished PCBA as usual ..even for prototypes ;-) ref des of components  
on it is clearly readable. Fine

BTW I see you have been using a OPA power, Does some parts of this OPA  
family can be a replacement of the TCA ?

Best regards, H

Re: TCA0372 sub
wrote:


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That's actually a production board. There was no prototype. I did the
design and layout at home, in a week during the initial hard virus
lockdown. It works, with a minor ECO.

The box was an experiment in laser blasting artwork onto an anodized
box.

We have sold.... TWO!

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The TCA is only good for 40 volts, and the OPA547 is rated for 60...
at about 12x the price. The OPA also has a resistor-settable current
limit, which helped my overall power scheme.

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--  

John Larkin      Highland Technology, Inc

The best designs are necessarily accidental.


  

Re: TCA0372 sub

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Bravo !

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