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 1 V produces a stream of ones and zeros that are high 90% of the time. With 16 bits of resolution, that percentage ideally corresponds to code 58982. A differential input of –1 V produces a stream of ones and zeros that are high 10% of the time and ideally results in code 6553 with 16-bit resolution. These input voltages are also the specified linear range of the AMC3336-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 stream of only zeros with an input less than or equal to –1.25 V or with a stream of only ones with an input greater than or equal to 1.25 V. In this case, however, the AMC3336-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.

Figure 7-4 Analog Input vs Modulator Output

The density of ones in the output bitstream for any input voltage value can be calculated using Equation 1 (with the exception of a full-scale input signal, as described in the Section 7.3.4.1 section):

Equation 1.