ESD protection design with the low-leakage-current diode string for RF circuits in BiCMOS SiGe process

摘要

The Low-Leakage-Current Diode String (LLCDS) in a BiCMOS SiGe process is proposed for on-chip ESD protection design in RF circuits. With an additional bias resistance, a voltage is applied to the n-well of diode string resulting in a significant reduction in the leakage current of the diode string under normal circuit operating conditions. The leakage current of LLCDS can be minimized under some selected bias resistance, which can be calculated from the derived equations. Such LLCDS can be used in the power-rail ESD clamp circuit, in cooperation with the small double diodes in the I/O pads, to achieve whole-chip ESD protection for RF ICs in SiGe process.