TIA-PIN combo in a ST connector package?

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I'm looking for a TIA-PIN combination in an ST connector package.

Bandwidth is almost irrelevant for my application, but low noise/dark
current and good sensitivity are musts.

Something like Hamamatsu's S8745 or S2592 series would be nice, but
AFAIK, those don't come in ST connectors, only TO-5/TO-8 and similar
packages.  (I've contacted Hamamtsu, to see if I'm wrong, but they're
not responding to my emails.)

OSI Fibercomm's FCI-H125G-010 comes in a ST package, but it has a high
bandwidth (1.25Gbps) which probably means the noise / dark current is
too high for me.  (I've got one, but I think it's dead.)

I've checked Advanced Photonix, but didn't see anything.  Checking some
standard optics and electronics supplies (ThorLabs, Edmund Optics,
DigiKey, etc) also came up empty.

Any suggestions?

Bob Pownall

Re: TIA-PIN combo in a ST connector package?

These are very different beasts that you've been looking at.

The Hamamatsu devices quoted are too large to fit in a standard ST

THe s2592 series doesn't have an integrated TIA, and the S8745 has a
huge 1Gig, gain resistor, so yes it will have excellent sensitivitym
but it will also saturate pretty quickly as well.. is this acceptable?
just how sensitive does it really need to be? It's also got a relata

Alternatively look at something like the Hamamatsu S6468 series, the
TO-18 package can fit in a standard ST receptacle. Gain is only 30k so
you may need some additional amplification if low light detection is
required. Hamamatsu can, or should be able to supply this with an ST
receptacle or alternatively you should be able to pick one up yourself,
and stick the photoreceiver in it. I've done this in the past with
similar devices.

Depending on your exact requirements it is also pretty easy to roll
your own TIA stage,  although it is not advice I like to give out too
often though as we also sell low noise swicthed reciever modules, ST
receptacles if you want:-)  For a good set of application notes have a
look at the Texas instrumetns web site, and check out some op amps like
opa111, or opa655 (for higher gain bandwidth requiremetns)..no that's
obsolete it's the opa656 now... I think the opa111 page has the links
to some good aplication notes. If you are genuinly looking at 1Gig of
gain this this may not be the route for your, but if you're looking at
100s of k then you can probably get something reasonable together,
especically as you're not worried about bandwith.



Re: TIA-PIN combo in a ST connector package?

David wrote:
<Summary: Several comments and suggestions relative to my request.>

Thanks for the suggestions, David.  Sorry to be so slow getting back to
you; I've been kind of swamped here.

You are, of course, correct about the 2592 not having an internal TIA.
I don't know what I was thinking.

I'm trying to detect a pretty faint signal, so the 1Gohm gain resistor
in the S8745 isn't likely to cause saturation but I should run some
trial numbers to make sure.  (Ooh.  I just did.  I do have a faint
signal, but I didn't fully think through the implications of a 1Gohm
gain resistor.  Just who buys this kind of device, and what do they use
it for?)

I wasn't aware that a TO-18 package would fit in an ST receptacle, so I
greatly appreciate the S6468 suggestion.

I'll contact Hamamatsu about getting the S6468 put in an ST receptacle.
  Failing that, I'll just follow your suggestion to buy my own ST and
put the S6468 in it.  (I assume you've epoxied the detector into the
receptacle?  Or does it just press-fit in?  Oh well, I'm sure I can
figure that part out once everything shows up.)

Again, my thanks for your time and assistance in answering my question.

Bob Pownall

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