Selecting a gain value of 0.4

[emr]

Hi all,

I have an analog signal which is in a range of -5V and +5V. I want to use MCP3204. In its datasheet, it is said that the analog input range of ADC is 0.25V ~ Vdd. I don't know if it is possible but I thought that if I can apply a gain of 0.4 to the signal and then offset that signal with 2.5V, ADC can read that signal. The signal range will be -2V ~ +2V. So the range for the ADC will be 0.5V ~ 4.5V (Because the offset voltage of 2.5 is added.)

Is there any way to do this practically?

Thanks in advance,

Best regards,

 

[kam1787]

gain is where Av > 1, so you want to use a resistor divider to acheive 0.4 of the Vin, then bias the input with the offset

 

[emr]

Hi kam1787,

Thanks for the quick reply. Is there any IC's to do this job or can a simple voltage divider do this?

Let's say I did the conversion. How can I offset that voltage practically?

I'm new to circuit design. So these question may be silly to you but I'm really having trouble.

Thanks in advance,

Best regards,

 

[godfreyl]

You can do it like this with 3 resistors.