A differential input signal of 0 V ideally produces a stream of ones and zeros that are high 50% of the time. A differential input of 250 mV produces a stream of ones and zeros that are high 89.06% of the time. With 16 bits of resolution, that percentage ideally corresponds to code 58368. A differential input of –250 mV produces a stream of ones and zeros that are high 10.94% of the time and ideally results in code 7168 with 16-bit resolution. These input voltages are also the specified linear range of the AMC1306M25-Q1. If the input voltage value exceeds this range, the output of the modulator shows nonlinear behavior as the quantization noise increases. The output of the modulator clips with a constant stream of zeros with an input less than or equal to –320 mV or with a constant stream of ones with an input greater than or equal to 320 mV. In this case, however, the AMC1306M25-Q1 generates a single 1 (if the input is at negative full-scale) or 0 (if the input is at positive full-scale) every 128 clock cycles to indicate proper device function (see the Section 7.3.4.1 section for more details). Figure 7-4 shows the input voltage versus the output modulator signal.

The density of ones in the output bitstream can be calculated using Equation 1 for any input voltage (V_IN= V_INP – V_INN) value with the exception of a full-scale input signal, as described in Equation 1: