HSMS-2829 Diode Array

[GizmoWizard]

Does anyone know if there is a drop-in replacement for the HSMS-2829 crossover, ring quad diode array that's used in double-balanced mixers? I was floored when I found out that this device has been discontinued—they're widely used in RF communications and test equipment.

I'd rather not have to change a half-dozen printed circuit boards if I don't have to. Any help would be appreciated.

 

[ronsimpson]

HSMS-2829

Sorry I can not find a replacement. I also have the same problem.

 

[unclejed613]

mouser shows this as a replacement, but PIV is only 4V, and If is 110mA

https://www.mouser.com/datasheet/2/196/Infineon-BAT15SERIES-DS-v01_02-EN-85097.pdf

also found this: BAT54XY https://www.newark.com/nxp/bat54xy-115/small-signal-schottky-diode-dual/dp/34R2957 it's a quad in two sections with 6 pins. to get the quad crossover configuration 2 jumpers are needed from 1 to 5, and 2 to 4

 

[GizmoWizard]

Thanks for the info guys. Looks like I’m going to have to spend a bunch of time at the computer re-wiring mixer sections.

1/A special thanks to Agilent.​

 

[unclejed613]

what i find surprising is that some company like On or Vishay didn't buy the process and begin making replacements. it looks like that crossover quad solves a lot of PCB layout problems for double balanced modulators, which is probably the sole reason it was made in that arrangement.

 

[ronsimpson]

what i find surprising is that some company like On or Vishay didn't buy the process and begin making replacements. i

I chose this part because I needed 4 matched diodes. Low capacitance. Very fast.
I think the volume on this part is very low. The silicon is very special. (hard to make)
Probably once a year companies dump the bottom 10% of their parts. (by profit)
This puts some of us out of business.

 

[unclejed613]

yeah, i figured the diodes had to be matched, which is why i didn't list the tons of "dual-series" pairs that came up. unfortunately, balanced modulators are easy to do in DSP code, so that reduces the amount of "real hardware" modulators in use by radio manufacturers. i figured such parts might be common in test equipment and radios that use balanced modulators for signal generation and up/downconversion, but it seems a lot of such functions have been moved into DSP, making most equipment a "black box" with very little of the work being done by real components.

hopefully, the 6-pin quads aren't too much hassle to use in place of the 4-pin ones. i know soldering jumpers to SMT devices can be a PITA.

 

[GizmoWizard]

I think all of these points are valid. Broadcom started dumping more than 1000 parts beginning last December. All of the HSMS series are gone as well as most of their limited -function devices. Perhaps more going on than the obvious.

 

[unclejed613]

sounds like they're dumping the discrete device end of their fabs. good opportunity for On or Vishay to pick up some new product lines (i would have included Fairchild, but they were recently bought by ON).