Voltage-Controlled Amplifier Designs for a Field-Programmable Analog Array

Lanterman AD, Hasler JO. Voltage-Controlled Amplifier Designs for a Field-Programmable Analog Array. J Audio Eng Soc. 2022;70(12):1048-1056. doi:10.17743/jaes.2022.0054

@article{Lanterman2022_22026,
  author = {Lanterman, Aaron D. and Hasler, Jennifer O.},
  title = {{Voltage-Controlled Amplifier Designs for a Field-Programmable Analog Array}},
  journal = {Journal of the Audio Engineering Society},
  volume = {70},
  number = {12},
  pages = {1048--1056},
  year = {2022},
  month = dec,
  publisher = {Audio Engineering Society},
  doi = {10.17743/jaes.2022.0054},
  url = {https://doi.org/10.17743/jaes.2022.0054}
}

TY  - JOUR
TI  - Voltage-Controlled Amplifier Designs for a Field-Programmable Analog Array
AU  - Lanterman, Aaron D.
AU  - Hasler, Jennifer O.
T2  - Journal of the Audio Engineering Society
J2  - J. Audio Eng. Soc.
VL  - 70
IS  - 12
SP  - 1048
EP  - 1056
PY  - 2022
DA  - 2022/12/06
DO  - 10.17743/jaes.2022.0054
UR  - https://doi.org/10.17743/jaes.2022.0054
PB  - Audio Engineering Society
LA  - en
AB  - This paper explores voltage-controlled amplifier (VCA) designs based on operational transconductance amplifiers (OTAs) on a floating-gate--based Field-Programmable Analog Array (FPAA). Although preconfigured OTAs are available on the target FPAA, their gain must be fixed during the programming stage. Hence, the OTA that forms the variable-gain element the VCA must be constructed from the individual transistors that are also available on the FPAA. The current output of this more-flexible OTA is converted to a voltage via one of the built-in fixed-gain OTAs. The authors show how the use of a special floating-gate OTA with voltage attenuation at its inputs arising from capacitor dividers (analogous to resistor dividers used in traditional printed circuit board--level VCA designs) helps prevent a diverging nonlinearity from ruining the current-to-voltage conversion process. This exercise highlights the counterintuitive challenges facing engineers moving from board-level audio design with off-the-shelf chips and discrete bipolar junction transistors to very large--scale integration--level design with complementary metal oxide semiconductor technology.
ER  -