Quick question!

david jenkins · Post by **david jenkins** » Mon Dec 24, 2007 9:33 pm

Regarding the zener diode D7, 1N4733 in the TPS Vref circuit - will any 5.1v zener be OK there, or is there a minimum requirement for wattage?

It's just that I can get BZX79C 5.1v (0.5W) or BZV85C 5.1v (1.3W) really easily after Christmas - otherwise it's mail order for just 1 component...

David

BTW: Merry Christmas to everyone!

MartinM · Post by **MartinM** » Mon Dec 24, 2007 9:56 pm

Your BZV85C 5.1v (1.3W) will be fine .... and the other one will almost certainly be fine also, but best use an over-specc'd one than under.

Happy Christmas to all too!

david jenkins · Post by **david jenkins** » Wed Dec 26, 2007 9:46 am

Cheers Martin,

Just one more question - the L1, 1uH inductor for the TPS - how critical is this value? Presumably it's part of the circuitry to provide a stable reference voltage, but would a 2.2uH work OK?

It's another case of 'I can get this one easily, anything else is a bit harder'!

David

MartinM · Post by **MartinM** » Wed Dec 26, 2007 8:34 pm

That's almost certainly fine too - the circuit around L1 helps prevent any noise picked up on the Vref line to the TPS getting back into the MJLJ and the value isn't critical.

david jenkins · Post by **david jenkins** » Wed Dec 26, 2007 9:52 pm

That's what I thought - it didn't appear to be any sort of critical tuned circuit!

Many thanks.