Buffer based on source electrode follower

Abstract

The invention discloses a buffer based on a source electrode follower and belongs to the technical field of analog integrated circuit design. The buffer comprises a pseudo differential input level, a cross coupling common source level, a current source and a capacitance load, wherein the pseudo differential input level is used for receiving a difference input signal; the cross coupling common source level is connected with the pseudo differential input level, used for forming negative resistance and offsetting output resistance of the buffer; the current source is connected with the pseudo differential input level and used for providing branch current of the buffer; and the capacitance load is connected with the pseudo differential input level and used as output load of the buffer. The negative resistance is formed by the cross coupling common source level, so that the buffer offsets the output resistance of the high-speed buffer and realizes unity-gain buffering output. The buffer based on the source electrode follower realizes ultra-high speed, the unity-gain buffering output and high dynamic characteristics by theoretical analysis and simulation verification.

Description

technical field [0001] The invention relates to the technical field of analog integrated circuit design, in particular to a buffer based on a source follower. Background technique [0002] The all-parallel analog-to-digital converter (flash ADC) is the fastest conversion speed among various types of analog-to-digital converters, and it is mainly used in the field of data acquisition with low precision and ultra-high speed (sampling frequency greater than 1GHz). figure 1 A schematic diagram of an analog front-end circuit of an all-parallel analog-to-digital converter is shown, which mainly includes an open-loop sample-and-hold circuit, an ultra-high-speed buffer and a pre-amplifier. Usually, since the fully parallel analog-to-digital converter needs to process the input analog signal in parallel, it also requires 2 N -1 pre-amplifier is connected in parallel to increase the input capacitance, therefore, it is necessary to add a super high-speed buffer at the output of the op...

AI Technical Summary

Problems solved by technology

[0009] In order to solve the problems of existing high-speed buffer signal gain less than 1, large analog input signal loss and poor dynamic performance, the present invention proposes a buffer based on a source follower, and the buffer includes:

Images