Abstract
This paper deals with a single-stage single-ended inverter-based Operational Transconductance Amplifiers (OTA) with improved composite transistors for ultra-low-voltage supplies, while maintaining a small-area, high power-efficiency and low output signal distortion. The improved composite transistor is a combination of the conventional composite transistor and forward-body-biasing to further increase voltage gain. The impact of the proposed technique on performance is demonstrated through post-layout simulations referring to the TSMC 180 nm technology process. The proposed OTA achieves 54 dB differential voltage gain, 210 Hz gain–bandwidth product for a 10 pF capacitive load, with a power consumption of 273 pW with a 0.3 V power supply, and occupies an area of 1026 μm2. For a 0.6 V voltage supply, the proposed OTA improves its voltage gain to 73 dB, and achieves a 15 kHz gain–bandwidth product with a power consumption of 41 nW.
Highlights
The development of electronic devices that are increasingly less dependent on battery charging requires Integrated Circuits (ICs) able to operate with Ultra-Low-Voltage (ULV) supply with an Ultra-Low-Power (ULP) consumption
It consists of a series connection of two independently forward-body-biased N-type Metal-Oxide Semiconductor (MOS) transistors MN1 and MN2, as first proposed in [20] and described in detail in [19], by using the Unified Current Control Model (UICM) all-region transistor model [22]
The small-signal circuit of this Operational Transconductance Amplifiers (OTA) is shown in Figure 6b, where the corresponding transconductance and output conductance are represented as Gm and Go, and its unloaded low frequency voltage gain AV can be modeled as Gm/Go, as described in Equation (8)
Summary
The development of electronic devices that are increasingly less dependent on battery charging requires Integrated Circuits (ICs) able to operate with Ultra-Low-Voltage (ULV) supply with an Ultra-Low-Power (ULP) consumption. An improved single-ended OTA has been proposed in [19], exploiting the properties of improved composite transistors [20] into a variation of the bulk Nauta inverter-based OTA [21]. This approach improves the voltage gain for a single-stage amplifier but shows a limited input voltage swing. This work further exploits the improved composite transistors of inverters [19] into a single-ended version of the fully differential OTA in [14] This results in an enhanced voltage gain, a higher linearity and a lower power consumption at the minimum supply voltages.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
