L
legg
Guest
On 30 Oct 2004 18:40:55 -0700, david.pariseau@sbcglobal.net (David
Pariseau) wrote:
Are you observing surface-mount part advisory re connections to pin2?
Are you making measurements with other mains-powered equipment when
the circuit is live?
Are you correctly identifying L and N?
If external (output) connections to the reference are intermittent,
are you sure that the common line is mating first and opening last on
each and every make/break event?
RL
Pariseau) wrote:
I'm using an LM4040-5.0 as a 5 volt reference in a circuit tied to the
AC mains that has to be able to run from 80-264VAC.
___ ___
Line ------>|-------|___|---+--|___|------+---+
1N4005 1K | 450K | |
| | |
--- - ---
3.3uf --- LM4040-5.0 ^ --- 0.1uf
| | |
| | |
Neutral -----------------------+-------------+---+
For some reason the LM4040 fails when I apply power to the circuit
(I'm currently using ~120VAC). The 450K resistor should be limiting
the current into the reference to 377ua (170VDC / 450K), well below
the maximum reverse current of 20ma and above the minimum operating
current of 70ua.
Your circuit is tied to the mains - what else is it tied to?
Are you observing surface-mount part advisory re connections to pin2?
Are you making measurements with other mains-powered equipment when
the circuit is live?
Are you correctly identifying L and N?
If external (output) connections to the reference are intermittent,
are you sure that the common line is mating first and opening last on
each and every make/break event?
RL