I. Introduction
The applications of floating gate transistors for non-volatile storage of analog information are numerous [1]–[3]. They can generally be divided into two big fields. One is the trimming of analog circuits to counter mismatch or threshold voltage shifts, e.g. input offset of an operational amplifier (op-amp). The other is their use in reconfigurable analog circuits. They can either be used as non-volatile switches, so they decide how circuit elements are connected, or to tune the circuit elements themselves, e.g. the bias current of an op-amp stage [3]. For both applications, a storage of information for the life-time of the chip is preferable. Nonetheless, if retrimming during operation is possible or even wanted in order to track changes through aging or temperature, a retention time of hours or days is sufficient. The same holds true for reconfigurable hardware such as FPAAs (Field Programmable Analog Arrays). It can be expected that they might be reconfigured on a regular basis to prototype different circuits, so a data retention of days or months might be acceptable.