MOS transistors operated in the lateral bipolar mode and their application in CMOS technology

TLDR

The paper investigates operating an MOS transistor in lateral bipolar mode. The authors describe and qualitatively analyze the operation of the MOS transistor as a lateral bipolar device. The study demonstrates that this configuration yields a high‑gain, low‑noise, CMOS‑compatible bipolar transistor, enabling accurate low‑current current mirrors, ultra‑low‑noise OTA performance, and a stable bandgap reference, with experimental circuits confirming these advantages.

Abstract

Operation of an MOS transistor as a lateral bipolar is described and analyzed qualitatively. It yields a good bipolar transistor that is fully compatible with any bulk CMOS technology. Experimental results show that high /spl beta/-gain can be achieved and that matching and 1/f noise properties are much better than in MOS operation. Examples of experimental circuits in CMOS technology illustrate the major advantages that this device offers. A multiple current mirror achieves higher accuracy, especially at low currents. An operational transconductance amplifier has an equivalent input noise density below 0.1 /spl mu/V//spl radic/Hz for frequencies as low as 1 Hz and a total current of 10 /spl mu/A. A bandgap reference yields a voltage stable within 3 mV from -40 to +80/spl deg/C after digital adjustment at ambient temperature. Other possible applications are suggested.