This lesson focuses on protecting the gates of MOSFETs that are connected to external pins from a charge device model ESD event. The architecture of the protection scheme includes a primary and secondary ESD clamps separated by an ESD resistor. The objective of the ESD input protection scheme is to make sure that the charge in the substrate of the chip as it flows to ground does not over voltage the gate oxide of the MOSFET. CDM clamps placed in close proximity to the gate and source are the secondary protection clamps and HBM clamps placed in close proximity to the pin or pad are the primary protection clamps.
This lesson show the difference between fail-safe and non-fail-safe CDM clamps. Input protection schemes for digital inputs, analog inputs, transmission gate inputs, bipolar inputs, and capacitors are discussed.
Lecture Notes for ESD Input Circuit Protection