Bridging the Gap between Design and Simulation of Low-Voltage CMOS Circuits

Abstract

This work proposes a truly compact MOSFET model that contains only four parameters to assist an integrated circuits (IC) designer in a design by hand. The four-parameter model (4PM) is based on the advanced compact MOSFET (ACM) model and was implemented in Verilog-A to simulate different circuits designed with the ACM model in Verilog-compatible simulators. Being able to simulate MOS circuits through the same model used in a hand design benefits designers in understanding how the main MOSFET parameters affect the design. Herein, the classic CMOS inverter, a ring oscillator, a self-biased current source and a common source amplifier were designed and simulated using either the 4PM or the BSIM model. The four-parameter model was simulated in many sorts of circuits with very satisfactory results in the low-voltage cases. As the ultra-low-voltage (ULV) domain is expanding due to applications, such as the internet of things and wearable circuits, so is the use of a simplified ULV MOSFET model.

A 5-DC-parameter MOSFET model for circuit simulation in QucsStudio and SPECTRE

“…The unified charge-control model (UCCM) in (7) describes the relationship between the terminal voltages and the normalized charge densities at source and drain.…”

“…The source and drain charge densities q S and q D are calculated using (7), which is an extended version of the UCCM that includes the velocity saturation phenomenon.…”

“…The Advanced Compact MOSFET (ACM) model has proved to be an interesting model for simulation and design [7], since the inclusion of only one short-channel parameter to the long-channel model rendered a 4-parameter model (4PM) that has successfully simulated MOS circuits operating at low voltages.…”

Design-Oriented All-Regime All-Region 7-Parameter Short-Channel MOSFET Model Based on Inversion Charge

“…In order to get further insight, Fig. 13 (d), (e), and (f) show a direct comparison between the UTSOI2 model and a state-of-the-art design-oriented 4-parameter model recently published [29], that we have fine-tuned for this technology and transistor geometry. It is clear to see that our proposed 7-parameter model offers a better representation of the V D dependency, while the 4-parameter model struggles to follow the actual MOST behavior when V D increases.…”

“…It is clear to see that our proposed 7-parameter model offers a better representation of the V D dependency, while the 4-parameter model struggles to follow the actual MOST behavior when V D increases. It is worth noticing that authors in [29] propose the 4-parameter model for lowvoltage applications, restricting the validity of the model, as can be observed in Fig. 13, to a low-V D scenario.…”