Hi,
I'm in the need of a current buffer/follower with unity gain. I have a low output resistance(250Ω) current signal, and I want to convert it into a high output resistance(anything higher than 250Ω) current signal. I have searched over TI's website, and the forum, but I couldn't find a current buffer, or any other product with this functionality. Here is my application:
I'm trying to design a circuit which will read a 4-20mA signal from a sensor, but it also will give an analogue output of the same 4-20mA signal, without any output resistance loss.
The only way I know to read a 4-20mA signal is running it through a series resistor, but in that way I will be cutting from the output resistance of my analogue output. I don't want that, because most of time people use a 250Ω resistor to read the 4-20mA signal. Therefore some sensors are designed to give max 250Ω output resistance. So if I use a 10Ω resistor to read the signal from the sensor, I will be leaving my analogue output only 240Ω output resistance.
I don't want that disadvantage, therefore I need a current buffer with a precise unity gain, so that I can read the 4-20mA signal, and output it with a high output resistance(at least 250Ω). I would appreciate any help.
Best Regards
Omer