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.
Some examples of situations where ADCs are necessary include:
- When data from the analog domain, through sensors or transducers, should be digitally processed.
- When transmitting data between chips through long range wireless radio links in high speed wireline transceivers between chips either on the same printed circuit board (PCB) or in a multi-die module.
- When used in analog test equipment (ATE) testing.
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 Flash ADC.
Overview of Flash ADCs
An “N-bit flash” or “parallel-architecture” ADC employs an array of 2n–1 comparators, as shown in Figure 1. The analog signal is applied simultaneously to each comparator, and each comparator has a different reference voltage on its other input with the voltages ascending in voltage increments equivalent to 1 LSB. A resistive voltage divider generates the reference voltages, so they’re as precise as the precision of the resistors.
Figure 1. Flash ADC Architecture
Flash ADCs are very fast because they generate an output in one ADC for every clock cycle. Unfortunately, requiring 2n-1 comparators can be a disadvantage of flash ADCs because they often lead to large power dissipation and a larger area. Due to these power and area constraints, flash ADCs usually have a resolution of no more than 10 bits.
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.
(Parts 3-5 coming soon)
To learn more about ADCs, check out our full white paper on the different ADC topologies and their applications: