About AMPCAL ADconverter ST7LITE29

[massimo23]

Posted on December 18, 2003 at 10:33

About AMPCAL ADconverter ST7LITE29

[massimo23]

Posted on December 18, 2003 at 08:17

Dear Forum, I would like to have more details about Ad converter implementation on STLITE29.

In particular, on the datasheet there is a very short explaination concerning bit 4 of ADCDRL register, the AMPCAL bit.

What I cannot understand properly is the function of this calibration bit, i can guess that it is suited to avoid large convertions´errors but...

Does anyone can help me?

thanks in advance

[jatin]

Posted on December 18, 2003 at 10:33

AMPCAL bit is used to calibrate the offset of the ADC. When the 0v is applied at the ADC input, the output of the amplifier corresponding to

0V input is non-zero(equal to V off ). This output corresponding to 0V input can be observed without having to apply 0V at the input. This is done by using the bit AMPCAL. So, convert 0V input once by the ADC, store it as an offset and subtract from all amplified-and-converted digital codes. It is used to calibrate the offset when the ADC amplifier is ON.