Schiller & Pandiscio
Digitally controllable analog switch
 An operational amplifier for generating an output analog signal at an output node representative of an analog signal fed to the non-inverting input of the operational amplifier. A controllable switch connects the output of the operational amplifier to the output node, and the signal at the output node is fed back to the inverting input of the operational amplifier. The controllable switch is responsive to a digital logic control signal for completing the circuit path between the operational amplifier and the output node in order to generate the output analog signal. A plurality of such operational amplifiers have their feedback path connected at a common output node. 
King Instrument Corporation
H H
H03K H03K
inventional inventional
David O. Edward J.
Neathery Riggs