One or Two Component 2mA Current Source

Apr 03, 2009 37 Replies

Yup..Same topo but with a depletion mosfet.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Oops.... Found loose cable connector on the cable modem.

I probably didn't screw it on enough and I think I put twists in the cable wire which made the connector unscrew itself over time. Carpet got changed.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

I was hoping for something stocked at Digikey. I have to pay brokerage when I order from Mouser. afaik there's no linear regulators from Digikey that can operate lightly with 170 Vin.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Example

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If I'm reading this right..

Pov=175V typ is derate at 2.4mW/C

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Interesting..

Graphs stop at around 120V.

Max V = 100V

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Can't handle Vds=170Vmax without help from more components.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Non-stock at Digikey. :( But will work for my app.

Huh..No internal diagram for the device. I wonder what's inside. Maybe it's a depletion mosfet..

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

I found your corrected part number post.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

...sounds like Maxim....

Brokerage?? Pricing is copetitive WRT Digikey.

Yup brokerage.. afaik.. Mouser only distributes from the US.

One time I ordered a smps from Mouser via UPS.. The brokerage amount imo was too close to the cost of the power supply. I was pissed. iirc there was tax on the brokerage amount too!

If Mouser send the parts by USPS (I think they don't) then I have to pay Canada Post $12.00 for brokerage.

There's no brokerage charge for US>Canada imports under $20.00 (might be $25.00)..

But... If I figure the part is worth the expense, I'll make it part of the design.

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Well you can always get a dual PNP (2 or 3 parts). Digikey has one at

400V from Zetex they aren't giving it away though $2.00.

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The cheapest solution would probably be two 300V or better PNP's (3 OR

4 PARTS). I'm guessing you don't need uA precision? They are widely available in small sc or sot packages.

I live in Canada too you can try and search maybe

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They may have a dual PNP 300V or better in stock if you really must keep it to 2 components. Just because it doesn't show on the search doesn't mean they don't have it. The search engine for both those sites suck. You have to dig around.

You're right, I fumbled the numbers. The J202 reference, though, puzzles me; that part isn't tight enough on drain current to suit the conditions, unless you get a selected unit. The data sheet current range is from 0.9 to 4.5 mA at zero Vgs.

Erggg... Well, if there aer small quantities or small $ lots that you want, then e-mail me the list and i will order them from Mouser and send them to you with customs form marked as "gift". I presume that would solve this "brokerage" business? PS: Mouser normally sends UPS.

In practice, they seem to be around 2mA but i have not tested enough to tell you the real spread. A resistor definitely would give decent precision.

If you order $200 CAD worth of stuff, shipping/brokerage is included, same as Digikey.

Best regards, Spehro Pefhany

"it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

I think Digikey has a warehouse in Winnipeg, Canada. Does Mouser have a warehouse in Canada too?

D from BC myrealaddress(at)comic(dot)com BC, Canada Posted to usenet sci.electronics.design

Both these places have warehouses in Canada. No brokerage fees.

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Future electronics is Canadian I think.

You can try alternative carriers with Mouser if they offer.I think UPS is the only carrier that charges exorbent brokerage fees. The other thing you can try if you can only use UPS with Mouser is express. The UPS guy who delivered my DSO said that I could have avoided the $220 brokerage fee if I used UPS express air.I try to avoid UPS like the plague!

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