Re: Fast monostable with a transistpor array

john larkin <jl@650pot.com> wrote:

On Sat, 15 Jun 2024 00:47:00 -0400, bitrex <user@example.net> wrote:
 

On 6/14/2024 7:10 PM, john larkin wrote:

On Fri, 14 Jun 2024 16:35:59 -0400, bitrex <user@example.net> wrote:
 

On 6/14/2024 12:33 PM, john larkin wrote:

On Fri, 14 Jun 2024 12:18:23 -0400, "Edward Rawde"
<invalid@invalid.invalid> wrote:
 

"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:
 

 
"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:
 

"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.
 
It offers three 8GHz NPN parts and two 5.5GHz PNP parts in a single array.
 
https://www.renesas.com/us/en/document/dst/hfa3046-hfa3096-hfa3127-hfa3128-datasheet?r=494216
 

 
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.
 

 
That is neither fast nor a monostable.

 
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.

 
It doesn't work!
 

 

 
There's no reason to use many-GHz parts in micropower circuits. One
reason is that the sim breaks.

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

 
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.
 

Wasn't  HFA originally a Harris part?
 
There are lots of dual (non-monolithic) diodes and bipolars and fets
around, but the monolithic arrays are mostly gone.

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

 
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.
 
Why do people avoid making clean 4-wire connections on schematics?

 
There's this new trend of breaking the circuit schematic up into little
boxes like this, it's nuts:
 
<https://hackaday.com/wp-content/uploads/2024/05/hadimg_desrev_ltc4040_6.png>
 
 

 
That's criminal.
 

 
Combining schematics and documentation in the same document is sort of
like a toothpaste and orange juice smoothie. I like orange juice, and
toothpaste is useful. However...

 
We keep a separate design notes folder. It can say a lot more than
could be hacked onto a schematic. I don't like a lot of comments on my
schematics.
 
 

I often annotate schematics with things like nominal voltages, dashed
rectangles to indicate circuit groups, and anything unusual that might be
mistaken for an error, such as a BJT used upside-down.

Makes it easier for others to understand.

(We also keep notes, markups from bringup, and so on. )

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs  Principal Consultant  ElectroOptical Innovations LLC /
Hobbs ElectroOptics  Optics, Electro-optics, Photonics, Analog Electronics