An Investigation of the Operating Principles and Power Consumption of Digital-Based Analog Amplifiers

Abstract

Digital-based differential amplifiers (DDA) are particularly suitable to low voltage digital integrated circuit technologies. This paper presents an exhaustive analysis of digital-based analog amplifiers to take advantage of today’s high-performance digital technologies, and of computer aided design (CAD), which is commonly employed to design integrated circuits. The operating principle and the main mathematical relations of digital-based differential amplifiers are discussed along with an exhaustive explanation of its operating regions and of the corresponding power consumption. These aspects, which are not discussed in the literature, are very important for the circuit designers. Finally, a detailed description of the design procedure of the UMC 180nm standard CMOS technology is provided.

A 0.3 V OTA with Enhanced CMRR and High Robustness to PVT Variations

“…The extremely low supply voltage does not allow for the exploitation of traditional design approaches such as tailed differential pairs and cascoding, and several design techniques have been studied for the design of efficient ULV OTAs. Solution based on a fully-digital approach (DIGOTA) [22][23][24] or operating in the time domain [25,26] have been proposed, but most of these techniques exploit analog approaches such as body-driving [27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45], floating-gate [46] and floating-body [47] devices, and inverter-based architectures [48][49][50][51]. The latter are often suitable for implementation using digital standard-cell libraries [52][53][54][55], thus simplifying the layout through the use of automatic place-and-route CAD tools and easing design portability among different technologies.…”