For high-frequency, high-amplitude inputs, the slew rate limitations of a differential amplifier can cause distortions in the output. This issue arises due to the inherent maximum current drive of a differential pair. If we instead use a modified version of Delbruck's bump/anti-bump circuit, the extra current drive in the transition period can improve the slew rate of the amplifier.
More specifically, this amplifier uses a Class-AB transconductor with an expansive nonlinear I-V characteristic. This circuit exhibits a hyperbolic-sin-like differential output current as a function of differential-mode input voltage. This differential amplifier exhibits a much higher effective slew rate than a traditional current-mirror differential amplifier.
