A method of creationediting maskswaveforms for an instrument invokes a mask editor from an application running on the instrument. The branch comprising a switch with a cascode MOS transistor, the circuit further comprises a bias circuitry adapted for dynamically generating a dynamic bias control signal so as to cause the cascode MOS transistor of the switch to be \u2018Off\u2019 in the low power mode. Separate erase blocks are established by shield plates.