Re: Spice Model for ADI 500MHz Four-Quadrant Multiplier Added to my Website

On 2025-04-16 18:14, john larkin wrote:

On Wed, 16 Apr 2025 17:57:23 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
 

On 2025-04-16 15:45, john larkin wrote:

On Tue, 15 Apr 2025 21:00:51 -0700, john larkin <jl@glen--canyon.com>
wrote:
>

On Wed, 16 Apr 2025 02:23:52 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>

john larkin <jl@glen--canyon.com> wrote:

On Tue, 15 Apr 2025 11:53:47 -0400, Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:
>

On 2025-04-15 08:30, FRAUBRJ wrote:> Hello,

Where can I find your AD834 spice model today?
>

<https://electrooptical.net/static/oldsite/www.analog-innovations.com/AD834_JT_SUBCKT.zip>
>
No warranties, expressed or implied.

>

Unless one is really picky, a simple BV block can multiply.
>
>

>
Do they come in TSSOP?
>
Cheers
>
Phil Hobbs

>
The BV price is better.
>
https://www.digikey.com/en/products/detail/analog-devices-inc/AD834JRZ/621076

>
I wonder if many peope have a need for an expensive precision analog
multipier in real life.
>

>
In test sets, probably.  Otherwise no.
>
Cheers
>
Phil Hobbs
(Who last used one in about 1995)

 Yeah, that sort of analog computing is a distant memory now.
 Test sets? How?

A simple test set that needs to compute the power dissipation in a complicated situation, for instance.
Making a measurement ratiometric by dividing out the strength of the excitation.
Test sets sometimes need to do relatively complicated things like that. If you're building one or ten, you'd probably far prefer to spend $50 and be done, rather than spend a week or two designing it like a product.

We do still use some MDACs, but we'd go all digital in the future on
that product. A 1 Ms/s 14-bit ADC is $2.

MDACs are pretty useful sometimes, because all-digital approaches are heavyweight.
For instance, in a control loop, you can get much better bandwidth with a 10 MHz, 14-bit AD5446 MDAC than a 1 MSa/s ADC plus processing plus some normal DAC.  It's very common that the resolution required for the loop gain is much less than you'd need for a fully digital solution, so you just use an analog loop and tweak it digitally.
Cheers
Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510
http://electrooptical.net
http://hobbs-eo.com