Reconfigurable and dense analog circuit design with two terminal Resistive RAM

Open Access
- Author:
- Saki, Abdullah Ash
- Graduate Program:
- Electrical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 08, 2020
- Committee Members:
- Swaroop Ghosh, Thesis Advisor/Co-Advisor
Abhronil Sengupta, Committee Member
Kultegin Aydin, Program Head/Chair - Keywords:
- Resistive RAM
Analog Circuit Design
Memristor
Amplifier
Low pass filter
hyperbolic sine
Gain
bandwidth
linearity
cut-off frequency - Abstract:
- Metal-oxide based bipolar Resistive RAM (RRAM) is one of the most promising candidates for future non-volatile memory. RRAM can be an excellent candidate for analog circuit designs due to unique properties like resistance modulation, compact area, backend-of-the-line (BEOL) fabrication compatibility, etc. However, designing analog circuits with RRAM will present a new set of challenges along with these potential benefits. However, recent literature only scratches the surface of this interesting prospect. In this work, I study a single RRAM behavior under temperature, voltage, and process variations from an analog design standpoint. The analysis uncovered several challenges like performance degradation due to non-linear \emph{I-V} relation of RRAM. An appropriate solution is devised to resolve the issues e.g., using RRAM Low Resistance State (LRS) to recover the loss. I also note that hyperbolic I-V characteristics of RRAM can inherently improve the linearity of RRAM based analog designs. I present four different types of analog circuits with RRAM namely a Common Source (CS) amplifier, a differential amplifier, a constant transconductance ($g_{m}$) biasing circuit, and an active low pass filter (LPF). Replacing polysilicon-based resistors with RRAM retains similar performance while offering various benefits. For CS and differential amplifiers, RRAM-based design offers a smaller area, higher bandwidth, reconfigurable gain, and potentially better linearity. Simulation results indicate that RRAM based amplifiers can achieve 2X area reduction, about 1.5X higher bandwidth with only ~ 9% reduction in gain. The resistance modulation property of RRAM is applied to realize a source degenerated amplifier with reconfigurable linearity, to a constant transconductance bias circuit to avoid resistance trimming, and to design a programmable active low pass filter.