The Transimpedance Limit

The transimpedance limit describes the maximum transimpedance that a transimpedance amplifier (TIA) can attain for a given bandwidth and technology. We analyze and compare this limit for a wide variety of TIA topologies thus exposing their relative merits. The topologies considered are the shunt-feedback TIA with single and multistage amplifier, the shunt-feedback TIA with feedback capacitor, the shunt-feedback TIA followed by a post amplifier, the shunt-feedback TIA with a current amplifier, the common-base/gate feedforward TIA, the shunt-feedback TIA with a common-base/gate input stage, and the shunt-feedback TIA with a regulated-cascode input stage. The analysis includes a discussion of the conditions under which the limit is realizable.