8.1 Overview

The TLA202x are a family of very small, low-power, 12-bit, delta-sigma (ΔΣ) analog-to-digital converters (ADCs). The TLA202x consist of a ΔΣ ADC core with an internal voltage reference, a clock oscillator, and an I²C interface. The TLA2022 and TLA2024 also integrate a programmable gain amplifier (PGA). Figure 5, Figure 6, and Figure 7 show the functional block diagrams of the TLA2024, TLA2022, and TLA2021, respectively.

The TLA202x ADC core measures a differential signal, V_IN, that is the difference of V_AINP and V_AINN. The converter core consists of a differential, switched-capacitor ΔΣ modulator followed by a digital filter. This architecture results in a very strong attenuation of any common-mode signals. Input signals are compared to the internal voltage reference. The digital filter receives a high-speed bitstream from the modulator and outputs a code proportional to the input voltage.

The TLA202x have two available conversion modes: single-shot and continuous-conversion. In single-shot conversion mode, the ADC performs one conversion of the input signal upon request, stores the conversion value to an internal conversion register, and then enters a power-down state. This mode is intended to provide significant power savings in systems that only require periodic conversions or when there are long idle periods between conversions. In continuous-conversion mode, the ADC automatically begins a conversion of the input signal as soon as the previous conversion is complete. The rate of continuous conversion is equal to the programmed data rate. Data can be read at any time and always reflect the most recently completed conversion.