Re: Fast monostable with a transistpor array

On Fri, 14 Jun 2024 15:19:08 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:

"john larkin" <jl@650pot.com> wrote in message news:m7uo6jhfuobfcjaps5o6hatlnm6ntnv84m@4ax.com...

On Fri, 14 Jun 2024 12:44:33 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
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"john larkin" <jl@650pot.com> wrote in message news:viro6jlt7h02ehbsq20em8uv5snn3736up@4ax.com...

On Fri, 14 Jun 2024 12:18:23 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
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"john larkin" <jl@650pot.com> wrote in message news:8epo6jhf5k5nbkkqp5ot9b6nq1lhoia870@4ax.com...

On Fri, 14 Jun 2024 11:08:56 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
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"john larkin" <jl@650pot.com> wrote in message news:hilo6j9dgctalpiu4v09rpdavf6fetm1cv@4ax.com...

On Thu, 13 Jun 2024 23:25:37 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
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"Bill Sloman" <bill.sloman@ieee.org> wrote in message news:v4f2nm$2augj$1@dont-email.me...

One option John Larjkin doesn't seem to have explored is using Renesas HFA3096 five transistor array as basis for his
mononstable
and level shifter.
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It offers three 8GHz NPN parts and two 5.5GHz PNP parts in a single array.
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https://www.renesas.com/us/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet?r=494216
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I put the NPN model parameters into a circuit designed by yourself.
It's late now but I got as far as Time step too small.
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That is neither fast nor a monostable.

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Yes ok it's an astable and certainly not intended to be fast.
It was intended only to see if the model worked. Nothing more.

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It doesn't work!
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There's no reason to use many-GHz parts in micropower circuits. One
reason is that the sim breaks.

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Most versions of the HFA3046 are obsolete. The only one left at
Digikey costs $12. It would be risky to design around that part.

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If it's obsolete or going obsolete then yes it would make no sense to use it.
I would guess that you get to do plenty of work because a manufacturer has suddenly decided to discontinue a part.
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Wasn't  HFA originally a Harris part?
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There are lots of dual (non-monolithic) diodes and bipolars and fets
around, but the monolithic arrays are mostly gone.

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What part would you recommend (single or dual) and does it have a working LTSpice model?

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Just pull up some parts from the standard library, some low current
NPNs like BC547 maybe. Look for low capacitances if you care about
that; the HFAs are good in that respect.

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Yes but BC547 sounds almost as ancient as BC107
Are they still in production?

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It was just an example of a library part, but Digikey will sell you a
million pieces.
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What would work well at a GHz or two or more?

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For switching? Tuned RF?

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I meant a specific npn part and maybe also pnp which is not going obsolete.
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You can search Mouser or Digikey for a multi-sourced part.

Sadly, fast PNPs are mostly going EOL, faster than NPNs. And all the
good things, like GaN and SiC and phemts, are n-types. Nature must
dislike P-things.

Designing with disctetes is educational, but nowadays ICs are the
practical winners. Like wideband MMICs for 10 cents, opamps and
switching regulators for 15.

Gotta move up the abstraction stack.