How big a difference between BAT46 and BAT29?

[Mark Hammer]

Question pretty much says it all.  Can I sub a BAT29 for a BAT46 in a clipping circuit and get similar performance?

[Ice-9]

They are both general purpose small signal schottky diodes so I douubt there would be any real noticable difference. I would just say give it a go.

[frequencycentral]

17?

[Mark Hammer]

17?

Took me a second, there, but this tattered brain finally got it. 
Point taken.

[frank_p]

17?

Took me a second, there, but this tattered brain finally got it. 

http://www.youtube.com/watch?v=dPgbMAdAsbI

[Ice-9]

17?

So Rick, are you saying you need 17  bat29's in series to make a 46 ?

[DavenPaget]

You can , but the BAT29 might blow . It has only 5V peak repetitive chance before it is gonna blow .
You can use the BAT42/85 instead . Remember in the world of 9V boosters , you really shouldn't use a 29 .

[Mark Hammer]

Even for audio signal?

[DavenPaget]

Even for audio signal?

Audio ... 2.5Vpp probably but 7Vpp , you're gonna probably see something go up in smoke .

[Mark Hammer]

Ah, well the application is a clone of a pedal that clips via Si diodes but allows the user to add Schottky type after wards.  So the preceding Si diodes assure that the signal will remain well within the limitations of the BAT29.

[DavenPaget]

Ah, well the application is a clone of a pedal that clips via Si diodes but allows the user to add Schottky type after wards.  So the preceding Si diodes assure that the signal will remain well within the limitations of the BAT29.

Ah , you know that , it isn't a problem .
Man , you're one of the senior members here on DIYSB 

[Mark Hammer]

I'd better be.  If anyone had that many posts in just 2 or 3 years, that would be classified as "clinical symptoms"!   

[DavenPaget]

I'd better be.  If anyone had that many posts in just 2 or 3 years, that would be classified as "clinical symptoms"!   

Absolutely  Or a troll . Which would have been banned earlier so .

[Mark Hammer]

i wired it up and fired it up last night, and it sounded fine.  Though I think I may keep my eyes peeled for other Schottkys, including BAT46 type, next time I buy some.

[DavenPaget]

42 or 85 is good . But there many other schottkys too just not that we know that many .
Not many shops sell schottkys because ... their maximum voltage is like 100V ?

[PRR]

> It has only 5V peak repetitive chance before it is gonna blow .

Break-down. Not "blow".

Backward on a 12V battery, infinite current tries to flow and it will burst.

Driven by typical opamps or other small-stuff, it is unlikely there will be more than 20mA available. Breakdown power dissipated is 5V*20mA or 100mW. The part does not have a dissipation rating but the thermal resistance suggests 100mW is safe. And that's assuming steady (DC) breakdown. In audio, half the time it will be conducting forward.

And most fuzz clippers are sorta-symmetric. There's a diode going the other way which will limit the back-diode to 0.4V, 0.6V, 1.6V, whatever, but probably nowhere near 5V.

I looked at BAT46 and BAT29 specs. They _do_ show different shapes. But device physics suggests they must be the same shape (shifted with device area) and the plots are either approximate or some kind of CYA worst-case limit.

[DavenPaget]

> It has only 5V peak repetitive chance before it is gonna blow .

Break-down. Not "blow".

Backward on a 12V battery, infinite current tries to flow and it will burst.

Driven by typical opamps or other small-stuff, it is unlikely there will be more than 20mA available. Breakdown power dissipated is 5V*20mA or 100mW. The part does not have a dissipation rating but the thermal resistance suggests 100mW is safe. And that's assuming steady (DC) breakdown. In audio, half the time it will be conducting forward.

And most fuzz clippers are sorta-symmetric. There's a diode going the other way which will limit the back-diode to 0.4V, 0.6V, 1.6V, whatever, but probably nowhere near 5V.

I looked at BAT46 and BAT29 specs. They _do_ show different shapes. But device physics suggests they must be the same shape (shifted with device area) and the plots are either approximate or some kind of CYA worst-case limit.

Oh ! Right . I damn near didn't consider the breakdown dissapation limit .

[DavenPaget]

I'd better be.  If anyone had that many posts in just 2 or 3 years, that would be classified as "clinical symptoms"!   

Absolutely  Or a troll . Which would have been banned earlier so .

I just realized at the rate i'm going about posting i'm gonna hit 18k in 2 years ...