High Speed Fast-Settling OTA
Dept.of Elec. and Comp. Engineering
University of Maine, Orono.
This ECE547 VLSI Design project consists of an Operational Transconductance Amplifier (OTA) to be used in the gainstage of a pipelined A/D Converter. The OTA is designed to charge 500fF switched capacitors with a settling time less than 5ns. The design is based on a telescopic architecture for optimal speed. There are nine fully differential OTA’s and a 250MHz ring oscillator on the layout.
MOSIS implements the device in AMI’s C5N process technology. The 0.5 micron minimum gate length is physically designed on a 0.15 micron grid. This constrains the gate length to a minimum of 0.6 microns. The die size is 1.5 X 1.5 mm and is packaged in a 40 pin DIP.
The project report (PDF) contains a project description with design and layout considerations and test results.