OUTPUT DRIVER FOR REDUCING PARASITIC CAPACITANCE OF PAD

摘要

PURPOSE: An output driver for reducing a parasitic capacitance of a pad is provided to reduce parasitic capacitance of the pad connected to an output driver terminal. CONSTITUTION: In an output driver for reducing parasitic capacitance of a pad, transistors for forming an output driver are serial-connected between the pad and a ground terminal. The transistors are formed in a Pwell(8) surrounded with a deep Nwell(4) and a barrier Nwell(6) formed in a semiconductor substrate(2). A plug(12) of the Pwell is connected to a negative bulk voltage terminal. The transistors has the lower threshold voltage than that of a normal transistor formed in the semiconductor substrate. The bulk voltage is a back bias voltage used to prevent leakage current of the memory cell.