A circuit includes an input stage configured to receive and amplify an input signal to produce an amplified signal, where the input signal is referenced to a higher voltage and is associated with a common mode voltage. The circuit also includes level shifter resistors configured to level shift the amplified signal to produce a shifted signal. The level shifter resistors are configured to provide a voltage drop so that the shifted signal is referenced to a lower voltage. The input stage may include multiple transistors floating in one or more isolated portions of a substrate, where the transistors perform amplification in the input stage. The circuit may also include circuitry configured to control current through the level shifter resistors so that the voltage drop depends on the common mode voltage of the input signal. In addition, the lower voltage may be between supply rails of the circuit.