cool part BUF802

And if enough people show an interest n the data sheet, Texas Instrument may actually make a few.

I got burned by one of Texas Instruments "test the market" data sheets a back in 1972, and I've not trusted them ever since.

Don't design it in until you've got your hands on a couple of parts. It says "pre-proproduction - only available from TI" and that usually means a lot of stories about low yields and waiting for the next batch.

Wow, almost as good as an LH0063, circa 1980. ;)

It's got higher bandwidth, for sure, and about the same slew rate, but can't do 40V supplies.

The LH4009, which arrived with the NS 1989 Linear Databook and was gone by the 1992 one, had a maximum slew of 10kV/us, and produced +-250 mA from 40V supplies.

The extra bandwidth is useful, for sure, as long as the supply voltages permit. ;)

Cheers

Phil Hobbs

TI is pretty good about making fast amps that work at nose-bleed voltages... like 10 volts.

The really dark days were about a dozen years ago, when there were no new HV op amps at all. The OPA140 and OPA2188 are the bomb.

Cheers

Phil Hobbs

OPA552 is great.

OPA547 is 60 volts with programmable current limit.

ADA4522 is a 55 volt chopamp! Who needs a 55 volt chopamp?

I roll my own kilovolt-level opamps. That's fun.

Yes, that "damn fast" ;-) (later censored) buffer.

SCNR

Reinhard

ctrl-f noise "Adobe Acrobat has finished searching the document. No matches were found."

Okey-dokey, then.

-- john, KE5FX

I'm doing a ridiculous APD front end for a customer--it uses our tried-and-true pHEMT bootstrap, with probably a single-ended pHEMT/SiGe cascode common-source gain stage with a noninverting CFA for the back end, hooked up as a bootstrapped TIA with a bandwidth in the high VHF.

I can't get the slew rate I need using a unity-gain compensated VFA, and the noise floor and supply headroom requirements have me blocked in between 1k and 2k for the feedback resistor, so I can't use one of the fast-slewing decompensated ones such as the OPA858 (A_V > 7).

They want it to recover from overload very very fast, so the APD voltage has to be clamped during overload. Otherwise the bootstrap cap will see almost the full DC current and start charging up to the wrong voltage. It could easily take tens of milliseconds to recover from that.

The kicker is, all that has to happen floating on a several-hundred-volt bias supply.

I suspect I may need to do one of your patented GaN FET tricks to drop the bias until the overload is finished--at 450V, the poor APD will get very hot very fast. That will decrease its gain sharply, and it could easily take tens of seconds for the temperature to recover. So there's some clarification and goal post moving required.

Fun.

Cheers

Phil Hobbs

Funny, it found it in your post. ;)

Cheers

Phil Hobbs

We do have an unfair amount of fun doing this stuff, and get paid too. Usually.

Email me the circuit if you'd like a review. I can do ridiculous.