A high-speed, high-gain OTA structure with a new compensation technique

In this paper a high-speed, high-gain operational transconductance amplifier (OTA) is designed and simulated in a 180-nm CMOS technology. The gain-boosting technique is employed in a two-stage OTA structure and a new compensation approach is developed. Using booster in the two stage OTA increases the open-loop DC gain while using the proposed compensation technique guarantees the stability of the structure. Moreover, using the simplifications made in the small signal analysis in this work provides an effective strategy in analyzing more complex circuit structures. In this case, an OTA with an open-loop DC gain of about 114 dB, unity gain bandwidth of about 305 MHz, phase margin of 61° and power consumption of 4.3 mW with a loading capacitor of 5 pF is designed and simulated.