EL7900

Your English is far better than my Italian. My Italian is limited to such phrases as "artichokes alla giudia" ;-)

Can you use a small value load resistor, such as 100 Ohms, use a +5V supply, ENbar grounded, and _gradually_ increase the light level, tabulating points as you go?

My guess is the enable device is too weak to support the current and collapses.

A really bad configuration! It should have been done by shunting the mirror input device. In series, all kinds of strange things can happen.

If you have access to a curve tracer, sweep output to Vcc, everything else open and report back. If you're lucky, it'll be one diode drop. If you're not lucky, the device will NOT be suitable for paralleling outputs. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
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I love to cook with wine.     Sometimes I even put it in the food.

Ahh, Hey as Phil pointed out that thing has a weird spectral response*. If your desktop lamp has an incandescent bulb then it can be putting out a lot of photons in the near IR.

George H.

*(I wonder how they managed to get a 'hole' near 630 nm... what they don't like HeNe's?)

That shouldn't matter. He's measuring output current, and it folds over before the spec limits.

--

John Larkin         Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation

Il 30/08/2012 21:50, snipped-for-privacy@fonz.dk ha scritto:

It's a Fluke 115, it should have a negligible input resistance for this measurement. Anyway, the sensor is a current source - that current will flow no matter the resistance of the ammeter.

Marco

Il 30/08/2012 22:02, Jim Thompson ha scritto:

When I did this experiment I got these results:

Vs = 3.3V Rload = 562 ohm Imax = 2.7 mA

Vs = 3.3V Rload = 180 ohm Imax = 2.7 mA

Vs = 5.0V Rload = 180 ohm Imax = 4.2 mA

But I wrote down only the maximum value of the output current reached. If you think it may be useful I can repeat the test tabulating the points.

I see...

Unfortunately I haven't a curve tracer, nor my friends.

Before select this component and start developing the board I explicitly asked to Intersil if it is suitable for this purpose. I have their emails ;) Last year I made a prototype with ISL29000: very similar, but obsolete now. There were no problems.

Now, a workaround should be:

- raise the Vsupply to 5V

- decrease the Rload

And for the next release, throw out this s&/*$t and use a bare pd instead ;)

Marco

Indeed ;-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
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I love to cook with wine.     Sometimes I even put it in the food.

Probably the passivation is half a wave thick at that wavelength.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
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hobbs at electrooptical dot net
http://electrooptical.net

--
Decrease Rload to zero ohms and the output current will probably be in
spec.

I don't think that's the problem. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

Even with Rload=0, it looks, from the cartoon schematic, that the collapse mechanism is still there. The upper pfet is probably wimpy. They may have done that to limit power dissipation at high illumination, but that was a dumb way to do it.

No response from Intersil?

It is surprising that the pd current could get high enough to divert milliamps of current to ground... or below ground. Could be that the cartoon schematic isn't the whole story.

--

John Larkin         Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation

As I said a couple of days ago...

Date: Tue, 28 Aug 2012 11:36:15 -0700 Message-ID:

Could be that the "cartoon schematic" is what is there, and that's the problem :-) ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

of 562 ohm.

too

2.7 mA,

below the

small

(2.048 V)

to a

that is

show any

as

if

-

and

the

--
"Insane" is the label you use to try to discredit critics whose
critiques escape you, and "unemployed" is what you call those of us
who, unlike you, don't have a yoke around our necks forcing us to work
if we don't have to.

--
The higher the load resistance, the sooner the compliance limit will
be breached, yes?

of 562 ohm.

too

2.7 mA,

below the

small

(2.048 V)

to a

that is

show any

as

sense if

then -

and

the

I don't have to work. But I enjoy it.

--

John Larkin         Highland Technology, Inc

jlarkin at highlandtechnology dot com
http://www.highlandtechnology.com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom laser drivers and controllers
Photonics and fiberoptic TTL data links
VME thermocouple, LVDT, synchro   acquisition and simulation

But that wouldn't cause a collapse, but rather the "flat-topping" claimed on the data sheet.

The enable device being Idss-limited _does_ cause a collapse. ...Jim Thompson

--
| James E.Thompson, CTO                            |    mens     |
| Analog Innovations, Inc.                         |     et      |
| Analog/Mixed-Signal ASIC's and Discrete Systems  |    manus    |
| Phoenix, Arizona  85048    Skype: Contacts Only  |             |
| Voice:(480)460-2350  Fax: Available upon request |  Brass Rat  |
| E-mail Icon at http://www.analog-innovations.com |    1962     |
             
I love to cook with wine.     Sometimes I even put it in the food.

g t

ys

Sure, it's broken. I was just trying to explain how even a desk lamp breaks it.

George H.

ed text -

t

ys

t -

Ahh, cute. Now they just need an NIR filter. Years ago I bought a PD from photonic detectors that had a built in filter to block visible light. I thought it'd be great for doing NIR stuff at trade shows, dang filter was polarization sensitive.

George H.

Il 31/08/2012 00:23, John Larkin ha scritto:

Not yet. They said "we don't know why it happens". After providing them further details: "we're going to forward the issue to the Product Line Engineers".

Marco

I don't know if it makes much differences however, a desk lamp may be producing 100/120 hz of light and your measuring methods could be bogus..

THis is assuming the PD will respond to that, which it should.

I would put a scope on that to see if this is pulsing. If you don't have a scope, then put a AC voltage meter at the load to see if you can see any measured signal.

Jamie