0 . 5 μ W Sub - Threshold Operational Transconductance Amplifiers Using 0 . 15 μ m Fully Depleted Silicon - on - Insulator ( FDSOI ) Process

We present a low voltage, low power operational transconductance amplifier (OTA) designed using a Fully Depleted Silicon-on-Insulator (FDSOI) process. For very low voltage application down to 0.5 V, two-stage miller-compensated OTAs with both p-channel MOSFET (PMOS) and n-channel MOSFET (NMOS) differential input have been investigated in a FDSOI complementary metal oxide semiconductor (CMOS) 150 nm process, using 0.5 V threshold transistors. Both differential input OTAs have been designed to operate from the standard 1.5 V down to 0.5 V with appropriate trade-offs in gain and bandwidth. The NMOS input OTA has a simulated gain/3 dB-bandwidth/power metric of 9.6 dB/39.6 KHz/0.48 μW at 0.6 V and 46.6 dB/45.01 KHz/10.8 μW at 1.5 V. The PMOS input OTA has a simulated metric of 19.7 dB/18.3 KHz/0.42 μW at 0.4 V and 53 dB/1.4 KHz/1.6 μW at 1.5 V with a bias current of 125 nA. The fabricated OTAs have been tested and verified with unity-gain configuration down to a 0.5 V supply voltage. Comparison with bulk process, namely the IBM 180 nm node is provided and with relevant discussion on the use of FDSOI process for low voltage analog design. OPEN ACCESS J. Low Power Electron. Appl. 2012, 2 156