CHAPTER 8 – Wideband Amplification

Publisher Summary This chapter focuses on wideband amplification. Some amplifiers are performance-limited mainly by speed. Oscilloscope vertical amplifiers, pulse and function generator output amplifiers, and video and nuclear signal-processing amplifiers are often speed-limited. Fast amplifiers are usually open-loop limited-gain stages. The speed of an amplifier can be expressed by its response to a step input. For a single-pole amplifier, the response to a unit step input can be characterized by its risetime. Large-signal amplifier behavior occurs when a signal quantity reaches the limit of its linear range. The maximum slew rate of a signal is determined by its maximum instantaneous slope and amplitude. The full-power bandwidth of an amplifier is related to the maximum slew rate of a sinusoid that spans the dynamic range of the amplifier. Delay time is useful for measuring the propagation delay of linear logic circuits. As the number of amplifier stages increases, the bandwidth is reduced. For a fast-amplifier design strategy, the number of stages should be minimized. However, most amplifier designs also require a given overall gain.