15.2 Input Range Selection

You can select a gain setting for the inputs, which causes them to be amplified before they reach the A/D converter. The gain setting is controlled in software and can be changed anytime, so that you can use different gains for different input signals. In general, you should select the highest gain (smallest input range) that allows the A/D converter to read the full range of voltages over which the input signals will vary. However, a gain that is too high causes the A/D converter to clip at either the high end or low end, and you will not be able to read the full range of voltages on your input signals.

The table below indicates the available analog input ranges. The polarity is set with bit ADPOL at page 2 base+13 bit 3, and the gain is set with the G1 and G0 bits in the register at base+3. The Gain value in the table is provided for clarity. The single-ended vs. differential setting (ADSD) has no impact on the input range or the resolution.

Polarity	Gain	ADPOL	G1	G0	Input range	Resolution(1LSB)
Bipolar	1	0	0	0	+/-10v	305µV
Bipolar	2	0	0	1	+/-5V	153µV
Bipolar	4	0	1	0	+/-2.5V	76µV
Bipolar	8	0	1	1	+/-1.25V	38µV
Unipolar	1	1	0	0	0-10V	153µV
Unipolar	2	1	0	1	0-5V	76µV
Unipolar	4	1	1	0	0-2.5V	38µV
Unipolar	8	1	1	1	0-1.25V	19µV