Hello,
I am using ZXCT1009 to monitor current flow from a 3V battery.
What is the maximum voltage that Vout of zxct1009 can be?
(i.e. the voltage at the "iout" pin.)
I.e supposing current from the "iout" pin is 1mA...then how big can i make the output resistor?.....would 1K8 be ok? Whats the highest resistance it could be?
2.5 volts is the minimum operating voltage of the ZXCT1009. And, since the '09 gets it's ground connection through the load resistor, it means that the minimum voltage between the +sense pin and the output pin, at any current, is 2.5V.
So, the highest output voltage that you can get with a 3V input is 0.5Volts.
If you look at the transfer characteristic curve you can see the max is almost a volt less than the power supply, which makes sense if you look at the little schematic of it in the example - it has an emitter follower output.
You know.. I don't know which is right. All I can do is tell you how I got there. I looked at the transfer curve. Lets say the lowest one - 2 ma. with .2 volts V sense. It looks like it needs 1.7 volts from Vin to Vout leaving 1.3 volts at 2 ma. or 650 ohms for the resistor. When I look at the top curve it looks like it takes 2.5 volts before it can deliver the full 10 ma. But I could also go for the 2.5 volts minimum but that would be kind of a wasted spec.