A Constant gm Current Reference Generator with Purely Off-Chip Resistor

• Published in: 2020 IEEE 63rd International Midwest Symposium on Circuits and Systems (MWSCAS) pp. 309 - 312
• Main Authors: Shahghasemi, Mohsen, Odame, Kofi M.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.08.2020
• Subjects: Bandgap Reference; Bias Generation; Capacitors; Constant Current Source; Constant g m; Gain; Generators; Reference Circuit; Resistors; System-on-chip; Transconductance; Transistors
• ISSN: 1558-3899
• DOI: 10.1109/MWSCAS48704.2020.9184538

Most analog circuits need a current reference generator to provide a stable biasing point for the transistors. Given the limited voltage headroom in advanced node technologies, there would be notable restrictions on the tolerance of the reference current deviation. Use of off-chip reference generators adds to the size of the system while the on-chip reference current generators are still partially dependent on the on-chip resistor values which is prone to technology variations. We proposed an on-chip reference generator with a fully off-chip resistor which has less sensitivity to the process variations. MonteCarlo simulation results shows that the proposed has 31% more precision compared to the conventional on-chip reference generator. Measurement results in 0.18 μm CMOS shows that the chip produces a stable reference current that is defined based on an off-chip resistor.