Instrumentation amplifiers suffer from a chronic output swing problem, even when the input common mode range and output voltage swing specifications are not violated. This is because the first stage of an instrumentation amplifier has internal output voltages that can clip at unspecified levels. The clipping itself is invisible to the user, but it affects the output swing adversely, usually causing a gain reduction and thus an invalid result. The new LTC~(~R)6800 and LT~(~R)1789-10 both solve this output swing problem, but in two extremely different ways. The LTC6800 incorporates a flying capacitor differential level shifter followed by a rail-to-rail output autozero amplifier. The LT1789-10 is a more classical three op amp instrumentation amplifier with the twist that it takes gain in the final stage.
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