VAS clamp diodes

[GK]

Here is a riveting topic for a new thread - fast low capacitance / high voltage diodes suitable for VAS anti-saturation clamping.

I need a >150V version of the 1N4148.

I'm pretty sure there is a 200V version out there but I can't for the life of me remember the part #.

Maybe someone can get this thread rolling by telling me what it is.

Cheers,
Glen

[unclejed613]

making a baker clamp?........
BAS20 is available from Newark (aka Farnell)

[syn08]

Onsemi's BAS21HT1 is what I'm using all along for such purposes. It's pretty good, although I'm told that some 1.5638MHz intermodulation products and a few hot headed recombining electron/holes pairs are clearly audible.

[unclejed613]

where's the 1.58Mhz junk coming from? the amp must be oscillating or picking up RF from a radio station

[andy_c]

Looks like Fairchild makes some leaded ones (DO-35) with a 250V rating also. Part number is BAV21 and datasheet is here.

[wg_ski]

Originally posted by unclejed613
where's the 1.58Mhz junk coming from? the amp must be oscillating or picking up RF from a radio station

It's probably coming from Sarcastia. Every audiophile knows that only Schottkys will do.

As to what to use for Baker clamps, I used to use the HER103, but I hear they've been discontinued.

[syn08]

Originally posted by wg_ski

It's probably coming from Sarcastia.

Precisely so

[unclejed613]

Trr is slower than the 1N4148. the 4148 is 4ns whole the BAV21 is 50ns.. i've seen Baker clamps with 2 1N4148's in series (which reduces the capacitance to 2pf).

[syn08]

Originally posted by andy_c
Looks like Fairchild makes some leaded ones (DO-35) with a 250V rating also. Part number is BAV21 and datasheet is here.

1SS244T-77 from Rohm, available at Mouser, is a good leaded option.

[andy_c]

Originally posted by unclejed613
Trr is slower than the 1N4148. the 4148 is 4ns whole the BAV21 is 50ns.. i've seen Baker clamps with 2 1N4148's in series (which reduces the capacitance to 2pf).

Yeah, seems like you give up some on that in exchange for high-voltage capability. Same with the Rohm device that Ovidiu mentioned too.

Still, I'm really glad Glen started this thread, as I'm getting ready to order some parts. This thread made me look harder than I previously had. Mouser has the Rohm device for 5 cents each and the Fairchild device for 6 cents. Glad to see that these kinds of parts aren't in the dreaded "audiophile unobtanium" category .