The CTSD16 has six single-ended analog inputs and four differential inputs that can be placed in single-ended mode by the CTSDINCHx bits in the CTSD16INCTLx registers. These single-ended modes use the fully differential path of the CTSD16 by internally tying the negative input to the V_REFBG/V_eREF+ signal. This means for the differential inputs in single-ended mode, the external pin normally tied to the negative input can be used for its alternate functions. Equation 8 through Equation 11 apply for full-scale range while in single-ended mode.

Equation 8.

Equation 9.

Equation 10.

Equation 11.

Where

• V_FSR is the full-scale range voltage
• V_I is the single-ended input voltage range for data-sheet specified performance
• V_R is the reference voltage

To ensure the measured voltage is within the single-ended voltage range, a simple voltage divider circuit can be used to condition the desired input signal. In single-ended mode, additional error may be introduced by noise when compared to a fully differential measurement. Equation 12 corresponds to the example circuit in Figure 10-7 and can be used after a range is chosen to limit differential input voltage to acceptable levels by solving for the external resistors R1 and R2.

Equation 12.

Where

• V_in is the single-ended voltage input to CTSD16
• V_m is the voltage to measure