Re: About TIAs

On Fri, 27 Dec 2024 14:14:31 -0000 (UTC), Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote:

Jan Panteltje <alien@comet.invalid> wrote:

 https://www.electronicdesign.com/technologies/analog/article/55250719/phlux-technology-tailoring-the-design-of-transimpedance-amplifiers-to-infrared-sensor-apps-part-2
 
I just drive the photo diode directly into the base of an NPN .....
 (ducks).
 

>
That’s basically a homebrew phototransistor, and may work great for
applications that don’t require high speed, low noise, or accurate
calibration. (There are lots of those.)
>
A slightly more advanced method is to replace the NPN with a cheap MMIC
amplifier. If you have at least a milliamp of photocurrent, that’ll get you
close to the shot noise, and it’ll be pretty fast unless the PD itself is
slow.
>
We sell fancier photoreceivers for much dimmer light, where it’s more
difficult to preserve both low noise and wide bandwidth.
>
Cheers
>
Phil Hobbs

MMICs are fabulous, fast, low noise, stable, and cheap. But be aware
that some, the newer self-biasing kind, get very weird at low
frequencies, and the data sheets hide it.