[paper] EKV-gm/ID Design Procedure

Marcello De Matteis

MATLAB-Assisted EKV-gm/ID Design Procedure for Two-Stage Miller-Compensated CMOS OTAs Starting from Closed-Loop Specifications

Journal of Low Power Electronics and Applications 16, no. 4: 53

DOI: 10.3390/jlpea16040053

Department of Physics, University of Milano Bicocca, Piazza della Scienza 3, 20126 Milano, Italy

Abstract: This paper presents a MATLAB-assisted EKV–gm/ID methodology for the systematic synthesis of fully differential two-stage Miller-compensated CMOS OTAs. A sensitivity-based analysis maps the required closed-loop gain, bandwidth, and noise into OTA-level targets. An EKV-inspired analytical model, independently calibrated for nMOS and pMOS devices, provides continuous ID/W, gm/W and gm/ID characteristics with errors below 5% in the design region. Noise-driven sizing explicitly accounts for the different carrier mobilities of the pMOS differential pair and nMOS active load. Transistor parasitic capacitances are estimated from bias-dependent Cgg–VGS characteristics, thereby capturing the reduced gate capacitance of devices operating in moderate or weak inversion. The framework automatically generates transistor dimensions, bias conditions, and Miller-compensation components. These parameters are transferred directly from MATLAB to CADENCE without simulator-assisted resizing or optimization, except for width quantization into 5 μm/300 nm fingers. In 0.18 μm CMOS implementation, MATLAB and nominal commercial CAD simulations predict, respectively, 61.80 and 59.27 dB DC gain, 430.78 and 431.52 MHz unity-gain bandwidth, 69.24° and 68.81° phase margin, 5.0 and 5.3 nV/√Hz input-referred noise at 100 MHz, and 1.426 and 1.314 mW core power. Robustness is assessed over 45 process-voltage-temperature corners, where the nominal solution remains close to the center of the evaluated performance distributions. The results confirm accurate nominal prediction and stable transistor-level behavior across PVT conditions and demonstrate that the proposed methodology accurately designs the OTA operating point, small-signal dynamics, and noise behavior, enabling transistor-level sizing directly from system-level specifications without iterative simulator-assisted optimization.

FIG.1: From Closed-Loop Specifications to a PVT-Verified OTA; MATLAB-Assisted EKV gm-ID Synthesis without Iterative Transistor Level Optimization

FIG.2: Design flow-chart for the two-stage Miller-compensated OTA.

[paper] Novel Design and Optimization and the gm/ID Ratio

A Novel Design and Optimization Approach for Low Noise Amplifiers (LNA) Based on MOST Scattering Parameters and the gm/ID Ratio

Juan L. Castagnola¹*, Fortunato C. Dualibe² Agustín M. Laprovitta¹ and Hugo García-Vázquez³

¹Facultad de Ingeniería, Universidad Católica de Córdoba, Córdoba 5017 (AN)

²Service d’Électronique et Microélectronique, Université de Mons (UMONS), 7000 Mons (BE)

³Departamento de Electrónica, Instituto de Astrofísica de Canarias (IAC), 38200 La Laguna (SP)

* Author to whom correspondence should be addressed.

Electronics 2020, 9(5), 785; https://doi.org/10.3390/electronics9050785

Received: 31 March 2020 / Revised: 30 April 2020 

Accepted: 9 May 2020 / Published: 11 May 2020

Abstract - This work presents a new design methodology for radio frequency (RF) integrated circuits based on a unified analysis of the scattering parameters of the circuit and the gm/ID ratio of the involved transistors. Since the scattering parameters of the circuits are parameterized by means of the physical characteristics of transistors, designers can optimize transistor size and biasing to comply with the circuit specifications given in terms of S-parameters. A complete design of a cascode low noise amplifier (LNA) in 65nm CMOS technology is taken as a case study in order to validate the approach. In addition, this methodology permits the identification of the best trade-off between the minimum noise figure and the maximum gain for the LNA in a very simple way.

Figure: gm/ID versus iD

Acknowledgement - This research was funded by Universidad Católica de Córdoba (Argentina), the Walloon Region DGO6 BEWARE Fellowships Academia Programme (1410164-POHAR, cofunded by the European Marie Curie Actions), the Belgian FNRS (Fond National pour la Recherche Scientifique) and the Argentinean MINCyT (Ministerio de Ciencia y Tecnología).