As discussed in Part 1 of our ADC Topology Series, Analog-to-Digital converters (ADCs) are used as an interface element between the analog and digital worlds to convert an analog input into a corresponding digital output.
There is a continuing trend in the industry toward achieving higher data throughput in both wired and wireless digital communication systems. This trend results in increasingly more demanding requirements from ADCs in terms of sampling rate and conversion accuracy. Meeting these specifications requires the use of different ADC topologies. One such topology is the Pipeline ADC.
Overview of Pipeline ADCs
Pipeline ADCs offer a unique balance between size, speed, resolution, and power. Pipeline ADCs consists of several stages, each containing a sample/hold stage, a low-resolution ADC and DAC, a summing circuit, and an inter-stage amplifier to provide gain for the next stage.
In a pipeline ADC as shown in Figure 1, the input is converted by an M-bit ADC (the M-bits represent the MSB) then converted back to digital using a DAC (usually with N-bit accuracy or higher) and subtracted from the sampled input. The residual error is then amplified and fed to the next stage. In theory, the resolution of the ADC should be the sum of the resolutions of the ADCs in each stage. In practice, some redundant bits are added for error correction. Once a stage is done with the current sample, it can start converting the next one. This is why pipeline ADCs have a large throughput.
Pipeline ADCs offer wide SFDR and low THD. This makes pipeline ADCs popular in communication systems, as it requires lower harmonic distortion.
Figure 1. Pipeline ADC Architecture
Vidatronic has several data converter IP blocks that offer flexible and efficient analog-to-digital and digital-to-analog conversion at different speeds to cover customers’ needs. Vidatronic data converters are silicon proven in several silicon processes and can be ported to any process required by our customers.
This blog post is part of a series. You can view the other posts in the series below.
(Part 5 coming soon)
To learn more about ADCs, check out our full white paper on the different ADC topologies and their applications: