[NLRS] MGA-86576 - eBay?

[Dr. Gerald N. Johnson]

There is that risk. Its not a part most of us can test without 
installing it in a circuit, and its stretched beyond ratings in the 10 
GHz DEMI preamp and transverter. It works quite well there. That would 
be the toughest test for fakes.

The MGA-86563 is the same chip in a different package that they are 
still making. Trouble is the package parasitics limit its rated range to 
6 GHz, and its falling off rapidly there. I think the package can be 
twisted to fit the footprint of the MGA-86576 for lower frequency 
applications than 10 GHz.

The MGA-30989 is in a larger package but that limits its rated 
performance to 6 GHz and the S parameters show 0.67 dB gain at 10 GHz. A 
suitable substitute at 5760 and down, a dud at 10 GHz. And it its rated 
range the P1 is about +23 dBm, a power device with decent NF.

The VMMK-3803 is a better part for 10 GHz operation for NF and gain over 
the MGA-86976, but it is inconveniently tiny. Its in an 0402 package 
with the ground pad in the middle and requires input bias to turn it on. 
That package I'm sure won't stretch to the traces made for the 76 
package (in that HP/Agilent numbering scheme the last two digits of the 
part number are package) and it doesn't appear to expose the pads for 
easy hand soldering. It might work with tiny strips of copper foil added 
in dead bug position.

Mouser has 490 of the MGA-86563 in stock at $2.60 each in small quantity 
bulk and 3000 on order to be sold as cut tape for the same price.

Mouser has 200 of the VMMK-3803 on order asking $7.60 each. They expect 
delivery next March 19 and factory lead time is 26 weeks.

Mouser has 794 of the MGA-30989 in stock at $2.68 each.

Digi-Key has 448 MGA-86563 in bulk and 7296 in cut tape for $2.91 and 
$2.99 each in single lots.

DK has 925 VMMK-3803 in blk for $8.03 each and 9125 in cut tape for $8.28.

DK has 233 MGA-30989 in bulk for $3 each.

Pictures of the adaptations of these parts to existing DEMI boards would 
be worth showing at Aurora and the rest of the season's VHF and 
microwave conferences.

The RFMD NBB-400T1 that DK has 13,516 in stock at $8.60 is in the same 
package as the MGA-86576. It has a 4 dB NF vs the original 2.5 dB NF 
rating. Rated to the same 8 GHz.

The RFMD NBB-300T1 is rated to 12 GHz, but the NF is 5 dB. DK has a pile 
in stock.

I believe DEMI has been using the NBB 310 or NLB 310 (plastic package vs 
ceramic) in transverters where NF isn't critical for a few years now in 
place of the original collection of ERA parts. Rated past 10 GHz with 5 
dB NF and a bit more power out than the ERA used formerly.

The RFMD SBW 5089Z is in a larger case rated to 8 GHz but with some 
performance data to 10 GHz, not a super NF of 4 dB at 6 GHz. DK has in 
stock.

DK has some Hittite and Micro Tech parts to cover the 1 to 18 GHz range 
all in QFN packages not interchangeable with the original part in 
question and all just under $100 each. Except for the packaged Hittite 
part with connectors for a mere $1601.28. They have only one of those in 
stock.

There may be other suitable parts available from our most friendly 
distributors Mouser and DK, I've searched enough for this morning.

Some substitutions may need attention to input and output impedance 
matching for optimum performance as well as changes in bias.

73, Jerry, K0CQ



On 12/8/2013 8:11 AM, John (JK) Kalenowsky, K9JK wrote:
>
>
> I see a Chinese seller with 5 for<$18 (not sure if there's a risk of
> the parts being fakes) and a US seller with 2 for $17.
>
> Your mileage/eBay experience may vary. Some assembly required.
> Batteries not included. I have no relations with any of these eBay
> sellers. (Other disclaimers ad infinitum.) --JK
>
>
>
>