Current-feedback topology — 1 GHz bandwidth at 6 mA supply
The MAX4223ESA+ is a current-feedback operational amplifier from Analog Devices, a topology that decouples gain-bandwidth from the closed-loop gain setting. With a -3 dB bandwidth of 1 GHz, it maintains flat gain well into the UHF band — suitable for video distribution, RF IF amplifiers, and high-speed ADC front-ends where a voltage-feedback amp would trade bandwidth for gain. The 1100 V/µs slew rate ensures the output can reproduce a 10 V step in under 10 ns without the slew-induced distortion that limits a slower amplifier's large-signal bandwidth. This matters when driving flash ADC inputs or cable loads that demand a clean edge at the full output swing.
Supply rails and quiescent current — 5.7 V to 11 V span
The 6 mA quiescent current per amplifier is modest for a 1 GHz current-feedback design — the same class of voltage-feedback amps at this bandwidth often draw 12-20 mA. Input offset voltage is trimmed to 500 µV max, and input bias current runs 4 µA typical — the current-feedback input stage has inherently higher bias than a JFET or CMOS input, so the source impedance driving the non-inverting input should be kept below a few kΩ to avoid offset drift from the bias current flowing through the source resistance.