I forgot the part, ST or NXP or something. Anybody remember?
- posted
3 years ago
I forgot the part, ST or NXP or something. Anybody remember?
ST L272. Pretty similar except with a wimpy abs max supply rating.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant
That's the part I was looking for the substitute for.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
ST L2720 looks interesing also.
Might be the same die, but that P/N is long gone AFAICT.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant
No idea, I just saw the L2720 in stock when I was looking at L272, and noticed the higher bandwidth.
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
-- Dr Philip C D Hobbs Principal Consultant
Octopart shows the STMicroelectronics L2720W13TR is available at Arrow with 4 in stock.
The datasheet is clean.
At USD$0.619 ea, we should buy 4 and put it out of its misery.
-- The best designs occur in the theta state. - sw
The 'B' version of TCA0372 differs from non-B only by max supply current; we verified that with ON. That's weird. Maybe some process change made them miss the 5 mA limit, so they had to invent B to sell the parts.
I wish data sheets always had a chart summarizing the differences between versions. Sometimes you can't tell. DGMS on packages.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
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
I use the TCA0372 to set Vhi and Vlo in my pulse generators.
but in this case, the max supply voltage spread is 31 volts.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
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
$1.7 million.
I use them as power supply regulators, as a fan controller, and as a relay driver too!
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.
Where do you see stock in other vendors? Octopart shows zero for DigiKey, Newark, Mouser, and Avnet. There are no listings for other vendors.
Why would digikey have a bunch on order when their datasheet shows it is obsolete.
-- The best designs occur in the theta state. - sw
Element 14 EMEA shows 1300-odd.
Because the datasheet is for a discontinued version, apparently. That fooled me too. Digikey is expecting another 1000 chips in by the end of March, or so they say.
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant
There's an updated data sheet for the 0372, rev 13. The schematic is still wrong. That's a tradition, I guess.
Looks like the SO16W package only.
Probably a bit over the top for a TCA0372 application, but I've been seeing ads for these guys lately:
-- john, KE5FX
Yikes, $200 per opamp. $1065 in one case.
Apex was classicly a hybrid house, back when hybrids were popular. I bought an Apex HV opamp once, the noisiest amplifier I've ever seen.
-- John Larkin Highland Technology, Inc The best designs are necessarily accidental.
At IBM back in the late '80s, we used to use the Burr-Brown 3584s to run piezo tubes on STMs and bimorphs on force microscopes. I recall when the Apex PA84 came out it was a big improvement for about the same (big) money.
You're right about the noise though!
Since the piezo application was pretty slow, I built my own amps out of MTP1N1000s (the first 1-kV VMOS FET iirc).
Cheers
Phil Hobbs
-- Dr Philip C D Hobbs Principal Consultant
I used some apex opamps for a ~100V piezo drive. They 'upgraded' the part, and it was much noisier, not usable for us. When I compared spec sheets I found that they had changed the noise spec. But who would think the new part would be noisier? George H.
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