A 1-V DTMOS-Based fully differential telescopic OTA
The dynamic threshold MOSFET (DIMOS) in standard CMOS technology can be realized by connecting the body of a PMOS to the gate. The threshold voltage of a DTMOS transistor is reduced by forward bias of the source-body PN junction, making it possible to operate in low voltage circuits. In this paper, we propose a 1-V DTMOS-Based fully differential telescopic cascade OTA. The output swing and input common-mode range are enlarged by the DTMOS input pair. A concise bias circuit with negative feedback guarantees all transistors operate in the proper regions in all working conditions. A bulk-driven continuous time common mode feedback (CMFB) is designed and embedded in the biasing circuit, no extra current is consumed. The circuit is designed in 0.18 μm CMOS technology, simulations show that DC gain is 79 dB in typical condition and keeps above 70 dB in all working conditions, the input common mode range and output swing are enlarged to 0.4 V and 0.94 V respectively.