# Help needed in Photodiode Amplifier Design

Status
Not open for further replies.

#### IndiJones

##### Full Member level 2
I need to build a circuit using Photodiode that will receive light from ultraviolet incandescent lamp (50/60 Hz line voltage), amplify and filter the signal and give dc output depending on the amplitude of the light. I'll be using an ultraviolet Photodiode for this purpose. Any help would be highly appreciated. Thanks in advance!

##### Junior Member level 1
On 2002-04-02 04:25, IndiJones wrote:
I need to build a circuit using Photodiode that will receive light from ultraviolet incandescent lamp (50/60 Hz line voltage), amplify and filter the signal and give dc output depending on the amplitude of the light. I'll be using an ultraviolet Photodiode for this purpose. Any help would be highly appreciated. Thanks in advance!

As helping of the fellow EE is the point,
not the points, here we go :

1. Former Burr-Brown, now TI subsidiary, has
some NICE app-notes and op-amps and even
specific photodiode amps suitable for variety
of UV-photodiode amplification, which usually
need quite high-gain.

2. Infineon, former Siemens, has some cheap ( $10 ) UV-photodiodes that are quite sensitive, that they at least use to sampled for free as Eng. samples. 3. Boston Electronics have some "kick-ass" sensitive UV-photodiodes based on Silicon Carbide and other technologies, expensive, yes, but have some of the best performance, and bandwidth in some cases down to upper end of X-rays, below UV even, and visible bandwidth autolimited, so, may not even have to buy that expensive narrow-passband UV filter depending what you want. They also have parts with hybrid amps on the same photodiode die. 4. With UV-photodiodes, as there is giant current amplification, similar in design to pH amps in many ways, one needs really high-gain, high-CMRR low input noise FET amps, AD and BB have some of the best amps for this application, both have the app notes, this is related to earlier 1. The boards need high di-electric constant, no dirty fingerprints, special materials may help, and teflon stands or air-wiring may be of high performance boost. 5. If you need bass-pand filters, OptoSigma does have such. 6. If you are into the very expensive but good, hamamatsu has some good products also, but cost like hell, for low end apps the Infineon UV diode is just good. Hamamatsu has some nice app-notes, too, in addition to TI-BB and AD and Boston Electronics. 7. As your app is that low in requirements, you only need a$10 Infineon cheapest UV
photodiode, and some decent amp from BB or
AD be done with it. The BB nunmber was something like 201 or 202 or 203 or that
direction.

What I wrote on 2. - 6. apply to more
demanding scientific UV-applications in
scientific instruments, that require
higher dynamic range, performance, accuracy,
resolution, etc. Forget 2. - 6. until you
have gotten your simple UV lamp intensity-
photodiode-amp-a/d converter-micro deal
working first.

I know arrays of more high-end UV photodiode
manufacturers,but they are all overkills for
what you want, and also costwise, so, no
reason to list those right now.

Hope this helped you some,

instru freak ... Labx is great place
for scoring used sciencee instruments
for decent price from on-line auctions.
https://www.labx.com, if they are still going
as strong as they used to.

##### Junior Member level 1
Few more things:

1. Never heard of "incadescent" UV light,
they are usually either Deuterium lamps
as in UV spectrometers, or fluorescent
UV that do not have the phosphorus to
convert/filter the UV to visible, some
Xenon lamps have some higher end UV,
and there is a cheap 4 watt incadescent
bulb looking UV lamp at 254 nm that actually
still is fluorescent, in spite of looking
and very expensive as of yet, but will
push DVD data-storage capacities to some
new "UVD" land of yet much higher data-densities, and many plastics like in
dentistry are UV cured, so, perhaps UV
UV-R's and UV-RW's will be possible also.

2. PLEASE USE SAFETY GOGGLES if you work
with UV-light, as it is notorious of burning
skin from the shorter wavelenght UV light
completely. You should be able to find
protective goggles from laser/uv gear
selling companies, even perhaps from
Edmunds Scientific in the hobby end UV
apps.

#### IndiJones

##### Full Member level 2
Pardon my English! It is indeed a fluroscent lamp.

Status
Not open for further replies.