[sdiy] Analogue switches

[Florian Teply]

On Tuesday 12 August 2008 01:16:02 Tom Wiltshire wrote:
> Hi all,
>
> I've been reading up on Marc Bareille's Extrapole DG Xpander filter
> project. I was checking availability of the DG408 analogue switch
> chip and found a wide variety of manufacturers and price:
>
> Analog Devices, ADG408BNZ, £3.67
>
> Vishay Siliconix, DG408DJ-E3, £2.54
>
> Intersil, DG408DJZ, £0.93
>
> Would anyone care to speculate on the disparity in price and whether
> it represents any disparity in quality? Does anyone have any
> experience with any of these chips?
>
Well, i can not comment on that specific part, but i did face exactly the same 
question myself lately. I use a 412 though, which isn't a multiplexer but 4 
single switches in one case. Funny thing is, price order was reversed on that 
one whhen compared to what you gave.

So there was an expensive Intersil part and two made by Vishay Siliconix and 
Maxim. The Vishay and Maxim parts featured lower ON-resistance and faster 
switching times with about the same price (Maxim being 2 or 3 cents cheaper), 
so i spec'ed the Vishay part. Unfortunately, those beancounters were dumb 
enough to follow my remarks only half-heartedly (I use to mark parts with NO 
MAXIM in big red uppercase letters as they are known to be a PITA as a 
supplier of parts) and tried to hunt down the parts themselves. Long story 
short: I ended up with the expensive Intersil parts instead of the cheaper 
and better Vishay one...

In your case, I'd compare the respective Datasheets closely and side-by-side 
as i'd expect to see some improvements with the newer replacement parts from 
Vishay, no idea about ADI though.

Greetings,
Florian
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