*Article* **All-Standard-Cell-Based Analog-to-Digital Architectures Well-Suited for Internet of Things Applications**

**Ana Correia 1,2, Vítor Grade Tavares 3, Pedro Barquinha <sup>2</sup> and João Goes 1,\***


**Abstract:** In this paper, the most suited analog-to-digital (A/D) converters (ADCs) for Internet of Things (IoT) applications are compared in terms of complexity, dynamic performance, and energy efficiency. Among them, an innovative hybrid topology, a digital–delta (Δ) modulator (ΔM) ADC employing noise shaping (NS), is proposed. To implement the active building blocks, several standardcell-based synthesizable comparators and amplifiers are examined and compared in terms of their key performance parameters. The simulation results of a fully synthesizable Digital-ΔM with NS using passive and standard-cell-based circuitry show a peak of 72.5 dB in the signal-to-noise and distortion ratio (SNDR) for a 113 kHz input signal and 1 MHz bandwidth (BW). The estimated FoMWalden is close to 16.2 fJ/conv.-step.

**Keywords:** analog-to-digital converters; high resolution; digital–delta modulator ADC; noise shaping; all-standard-cell-based; Internet of Things
