RAIL-TO-RAIL OUTPUT STAGE SWING IS LIMITED BY Vcesat, Ron, AND LOAD CURRENT NMOS SWINGS TO RAILS LIMITED SWINGS T。 RAILS LIMITED BY SATURATION VOLTAGE BY FET" ON"RESISTANCE (-1002 Figure 1.7 In summary, the following points should be considered when selecting amplifiers for single-supply/rail-to-rail applications First, input offset voltage and input bias currents can be a function of the applied input common- mode voltage (for true rail-to-rail input op amps). Circuits using this class of amplifiers should be designed to minimize resulting errors. An inverting amplifier configuration with a false ground reference at the non- inverting input prevents these errors by holding the input common-mode voltage constant. If the inverting amplifier configuration cannot be used, then amplifiers like the OP284/0P484 which do not exhibit any common-mode crossover thresholds should use econd, since input bias currents are not always small and can exhibit different polarities, source impedance levels should be carefully matched to minimize additional input bias current-induced offset voltages and increased distortion. Again, consider using amplifiers that exhibit a smooth input bias current transition throughout the applied input common-mode voltage Third, rail-to-rail amplifier output stages exhibit load-dependent gain which affects amplifier open-loop gain, and hence closed-loop gain accuracy. Amplifiers with open-loop gains greater than 30,000 for resistive loads less than 10kohm are good choices in precision applications. For applications not requiring full rail-rail swings, device families like the OPX13 and OPX93 offer DC gains of 0. 2V/u V or more Lastly, no matter what claims are made, rail-to-rail output voltage swings are functions of the amplifier's output stage devices and load current. The saturation voltage(VCESAT), saturation resistance(RsaT), and load current all affect the amplifier output voltage swing10 RAIL-TO-RAIL OUTPUT STAGE SWING IS LIMITED BY Vcesat, Ron, AND LOAD CURRENT Figure 1.7 In summary, the following points should be considered when selecting amplifiers for single-supply/rail-to-rail applications: First, input offset voltage and input bias currents can be a function of the applied input common-mode voltage (for true rail-to-rail input op amps). Circuits using this class of amplifiers should be designed to minimize resulting errors. An inverting amplifier configuration with a false ground reference at the non-inverting input prevents these errors by holding the input common-mode voltage constant. If the inverting amplifier configuration cannot be used, then amplifiers like the OP284/OP484 which do not exhibit any common-mode crossover thresholds should be used. Second, since input bias currents are not always small and can exhibit different polarities, source impedance levels should be carefully matched to minimize additional input bias current-induced offset voltages and increased distortion. Again, consider using amplifiers that exhibit a smooth input bias current transition throughout the applied input common-mode voltage. Third, rail-to-rail amplifier output stages exhibit load-dependent gain which affects amplifier open-loop gain, and hence closed-loop gain accuracy. Amplifiers with open-loop gains greater than 30,000 for resistive loads less than 10kohm are good choices in precision applications. For applications not requiring full rail-rail swings, device families like the OPX13 and OPX93 offer DC gains of 0.2V/µV or more. Lastly, no matter what claims are made, rail-to-rail output voltage swings are functions of the amplifier’s output stage devices and load current. The saturation voltage (VCESAT), saturation resistance (RSAT), and load current all affect the amplifier output voltage swing