[christianw.]

Meine Antwort an Maxim:

Zitat:Hello Matthew,

thanks for your reply, i really appreciate your support.

At first, i fixed the issue you told me. I need to say, that the capacitive pull-up is a solution we have simulated and discussed with our engineering professor. I now did a simple voltage divider 10k-10k from VDD to AGND, /SHDN is connected to the middle (VDD/2).

There now is no connection from /SHDN to REG anymore.

For the measures, voltage is measured directly on the power-supply-plug on our testboard. (VDD to PGND)

The power-supply is a 12.6V Li-Ion cell which is capable of delivering 10 amps max.

I also crosschecked using a regulated power-supply (Delta Elektronika ES 030-5) - same result.

Having a 0R33 in the supplyline gives an inrush-current of nearly 8amps peak.

Testing the circuit with a battery is for the matter, that the regulated power-supply is showing some regulation influences on start-up, caused by the inrush current.

Concerning the attached measures, the yellow graph shows the power-supply line, while blue is either /SHDN or REG. As i said before, there is no external connection between those to lines anymore.

Results behave same as before, something strange is going on - even if /SHDN is connected via 10k directly to VDD.

Might there be some kind of punch-through?

Kindly regards,

Christian W.