Applications
There has been an ever-increasing need for higher speed and
lower power dissipation in high resolution analog-to-digital
converters. These converters find application in areas such
as wireless communications, high-energy physics, and measurement
and instrumentation equipment. In recent years, switched-
capacitor pipelined converters have emerged as an especially
attractive architecture for implementing Nyquist-rate quantizers
for medium to high resolution conversion with medium to high
conversion rates and reasonable power consumption. Floating-
point A/D converters have been shown to be useful in high
resolution applications in which the least significant bits are
not used when encoding large signals. Floating-point analog-to-
digital converters (FADC) employ nonuniform quantization and
typically dissipate less power and require less hardware than
comparable uniform quantizers. Due to the nonuniform nature of
the quantization, FADCs sacrifice a large peak signal-to-noise
ratio (SNR) for an increase in dynamic range. The key objective
in this research is to combine the features of a pipelined
converter and a FADC to reduce power dissipation, strigent
linearity requirements, and calibration complexity for a
high speed, high resolution converter.
Applications
Floating-point analog-to-digital converters have generally been
used for experiments in which the acquired signal is of a non-
repeatable nature such as those caused by explosions, impacts, or
earthquakes in which the initial high amplitude pulse is followed
by a low amplitude ringing component. Moreover, these converters
are useful in large dynamic range applications in high-energy
physics. In particular, floating point converters are utilized
in experiments for electromagnetic calorimeters for detectors
in colliding beam machines. Additionally, nonuniform converters
may be attractive for wireless applications in which low-
amplitude signals must be acquired and processed with a SNR of
40 dB - 70 dB.
Publications
D.U. Thompson, B.A. Wooley, " A
15-bit Pipelined Floating-Point A/D Converter ,"
1999 European Solid-State Circuits Conference Proceedings, Duisburg,
Germany,
pp. 170-173, Sept. 1999.
