bat85 replacement for coolaudio V2164

[ketem13]

Hi,
I'm working on the Benjolin circuit and I was stuck without the bat85 schottky diode.
Can I substitute it with 1n5819/1n60p which I have ?

Thanks

[ketem13]

Another question regarding the benjolin:
I am considering using the lt1054 to invert the 12v dc power supply and then use voltage regulator with it. I found that power-supply schematic from mutable instruments. Can I use it with the benjolin? but instead of using the 7805 and 7905 I will use of-course 7809 and 7909 ?

[MikeDB]

I don't know the circuit but I suspect not. The BAT85 is for small signals whereas the 1N5819 is for higher currents and has quite a high capacitance.

[neil.johnson]

Hi,
I'm working on the Benjolin circuit and I was stuck without the bat85 schottky diode.
Can I substitute it with 1n5819/1n60p which I have ?

Thanks

Which circuit are you building? Link to pdf would help. All the schematics I found only showed 914 diodes, which are not Schottky. Is this Schottky used for the missing rail protection? If so then 1N5819 would be fine.

Neil

[ketem13]

Hi,
I'm working on the Benjolin circuit and I was stuck without the bat85 schottky diode.
Can I substitute it with 1n5819/1n60p which I have ?

Thanks

Which circuit are you building? Link to pdf would help. All the schematics I found only showed 914 diodes, which are not Schottky. Is this Schottky used for the missing rail protection? If so then 1N5819 would be fine.

Neil

Hi,
I'm building the Benjolin from that schematic . while on that one there is no bat85 and either a forward protection diodes, I did see it in other schematic in this theard .

I actually build it to be a stand-alone device using 12v dc wallwart. I may skip the hole protection thing ?

[wackelpeter]

i might jump onto this train and ask if all of the 2164 IC's no matter which manufacturer should have those protection diodes? Or is it one some of those clones already build in, in case the power line fails?

[neil.johnson]

i might jump onto this train and ask if all of the 2164 IC's no matter which manufacturer should have those protection diodes? Or is it one some of those clones already build in, in case the power line fails?

The original SSM2164 and the V2164 clone suffer from the missing rail self-destruction problem.
The SSI2164 does not have this problem as the designer fixed it.

Cheers,
Neil

[Altitude909]

Hi,
I'm working on the Benjolin circuit and I was stuck without the bat85 schottky diode.
Can I substitute it with 1n5819/1n60p which I have ?

Thanks

If its just for reverse power protection, then yes. 5819 is used on Plancks II for that exact purpose

[MikeDB]

Hi,
I'm working on the Benjolin circuit and I was stuck without the bat85 schottky diode.
Can I substitute it with 1n5819/1n60p which I have ?

Thanks

If its just for reverse power protection, then yes. 5819 is used on Plancks II for that exact purpose

If it is for reverse power protection then the Bat85 is possibly the last device I'd choose ! 1N5819 much more suitable.

[synthetek]

i might jump onto this train and ask if all of the 2164 IC's no matter which manufacturer should have those protection diodes? Or is it one some of those clones already build in, in case the power line fails?

Looks like the Alfa clone has built in protection too. The data sheet says "The Alfa RPAR AS2164 is internally protected in situations where negative supply is turned OFF"

[wackelpeter]

Me again, was soldering the Thomas Henry VCF&VCA from the synth for the 21st century book the last few days and have not plugged it in and tested yet, but i came up with an question regarding the input protection i wasn't able to find an answer yet.

If there is more than one 2164 used in a board, would i only use one diode directly on the power supply or use a diode on each IC? Normally maybe one could be enough to protect all of them, but this doesn't inlcude any other failures to power like a broken trace to just one of the chips or something in that vein. Would it harm or make sense to put an schottky diode on each IC's negative rail and does it harm if the IC brand (like the As2164) already has an built in protection circuit? Could i face some problems or damage 2164's if there's essentially several schottky diodes in parallel at the designated negative rail inputs of the individual 2164's?

[MikeDB]

One is enough if they are all the ICs are wired to the same supply lines

[EATyourGUITAR]

1N914, 1N4148, BAT47

[socom93]

Me again, was soldering the Thomas Henry VCF&VCA from the synth for the 21st century book the last few days and have not plugged it in and tested yet, but i came up with an question regarding the input protection i wasn't able to find an answer yet.

If there is more than one 2164 used in a board, would i only use one diode directly on the power supply or use a diode on each IC? Normally maybe one could be enough to protect all of them, but this doesn't inlcude any other failures to power like a broken trace to just one of the chips or something in that vein. Would it harm or make sense to put an schottky diode on each IC's negative rail and does it harm if the IC brand (like the As2164) already has an built in protection circuit? Could i face some problems or damage 2164's if there's essentially several schottky diodes in parallel at the designated negative rail inputs of the individual 2164's?

You won't harm any already protected ICs by putting a diode but it is then useless.

For multiple 2164, only one diode should technically be enough but it totally depends on your layout and on the impedance of the -12V track, and the size of your board, and the distance between ICs, etc...
Again, a diode really close to each IC can't be a bad thing if you want (almost) 0% chance of triggering the power failuremode.

[wackelpeter]

Again, a diode really close to each IC can't be a bad thing if you want (almost) 0% chance of triggering the power failuremode.

That was, what i wanted/hoped to hear... as i do always build on stripboard and sometimes also do some errors, this was the question that i was looking for protecting the 2164's from my mistakes, if it's possible or if there where any unwanted side effects when doing this for each 2164IC on the same board... i still haven't found an circuit that i'd like to build with more than one 2164... but who knows... now knowing that i could, let's me sleep tight tonight.

thanks!

[JimY]

The reason Schottky diodes are chosen will be for the lower forward voltage. If a device has it's own protection diode, it will probably be normal silicon and so a higher forward voltage. The lower voltage Schottky will act before the internal diode and internal diodes are usually low current so a fault could blow them and then there's no protection at all if they were the only protection.
Another advantage of Schottky is that you can test across the circuit with your DMM diode test to be sure they are actually connected. If the forward voltage reading matches for the Schottky, it's good. Or, you can at least confirm connection from the diode legs to the power rail with a resistance/continuity test.

[bgreeves]

Hi,
I'm working on the Benjolin circuit and I was stuck without the bat85 schottky diode.
Can I substitute it with 1n5819/1n60p which I have ?

Thanks

If its just for reverse power protection, then yes. 5819 is used on Plancks II for that exact purpose

If it is for reverse power protection then the Bat85 is possibly the last device I'd choose ! 1N5819 much more suitable.

If the diode in question is the one meant to fix the original 2164's catastrophic power rail failure mode (and not in fact the ones intended for reverse power protection), then other very smart folks have suggested otherwise vvvvvv

I would not recommend anything other than a signal Schottky diode, as you want the protection diode to turn on before the unpleasant internal silicon junction (parasitic or otherwise) that causes smoke to turn on. If you use a 1N4148 or a germanium then there is no guarantee that the protection diode will turn on first. It is all about keeping the V- pin less than one diode drop away from the Gnd pin.

Neil

[neil.johnson]

If it is for reverse power protection then the Bat85 is possibly the last device I'd choose ! 1N5819 much more suitable.

For reverse power protection then MikeDB is entirely correct in recommending a power device such as the 1N5819, as this would be placed in series with the power supply and so has to handle the full load current of the module.

If the diode in question is the one meant to fix the original 2164's catastrophic power rail failure mode (and not in fact the ones intended for reverse power protection), then other very smart folks have suggested otherwise vvvvvv

The issue with the original SSM2164 (and copied into the V2164) is an internal silicon bug/feature and all that needs is a low-current clamp to keep the V- pin below a silicon diode drop (about 0.7V) above the GND pin. In that application a small signal diode like the BAT54 or BAT85 is sufficient.
This bug was fixed in the SSI2164. However for compatibility it is recommended to include the diode in case a builder uses the earlier devices.
More info here: https://www.njohnson.co.uk/index.php?me ... bsubmenu=3

So, we're both right

Neil