Recently, switched-current circuits have received great
attention because they offer potentially better performance in terms
of speed, low voltage power supplies, and accuracy in mixed-mode
analog-digital signal processing. In this thesis, the distortion
characteristics, DC offset and AC gain errors induced by the threshold
voltage, channel width, channel length, and...
A short-circuit-protected line-driver circuit is
particularly adapted for use in a CMOS differential line-driver
system, where one line-driver circuit provides a
true output signal, and another line-driver circuit
provides a complementary false output signal. A short-circuit
is sensed by measuring current through a secondary
pull-up transistor, and disabling a primary...
The core area of a conventional CMOS digital gate
array consists of only one size of NMOS device and one
size of PMOS device. Both primitives have fixed minimum
channel lengths, and this has significantly impeded analog
applications. This work has shown that by forming series
and parallel interconnections between...
A frequency compensation technique for increasing the
settling speed of two-stage operational amplifiers used in
switched-capacitor applications has been developed. By
properly decompressing the pole-zero doublet to form a
three-pole one zero system, the settling speed is increased
up to 50 percent as compared to the optimized two-pole
system.
A MOS biquadratic (biquad) filter employing the switched-current technique is
reported. The circuit uses current-mode processing which can offer wide
bandwidth, low voltage operation, and can be implemented with standard CMOS
technology. Examples of lowpass, highpass, and bandpass filters are given
which illustrate the synthesis procedures and the versatility of...
The output characteristics of a conventional GaAs depletion-mode MESFET device have been investigated. One of the important parameters of the small-signal GaAs MESFET model, g[subscript ds] (output conductance), is shown to be frequency and temperature dependent. Variations in g[subscript ds] are a serious problem in many analog and digital circuits...
A modeling technique for simulating the noise
performance of chopper-stabilized switched-capacitor
filters using SPICE2 is presented. A method for
selection of switched-capacitor network (SCN) stages
to be chopped and an op amp topology for low noise
applications are also outlined. Validity of the
modeling is verified by the close agreement...
Digitally-programmable filters have been an ongoing research topic for a number of years. The first such filters were FIR transversal filters using Charge-Coupled Devices (CCD's) and IIR recursive filters using switched-capacitor (SC) techniques. Although both techniques achieve excellent results, they require non-standard and/or additional IC fabrication steps. Low substrate doping...
The characteristic of the subthreshold current in a
GaAs MESFET exhibits a negative exponential function with
Vgs. After studying the behavior of this current in this
region over a range of temperature and drain bias voltages,
a subthreshold current model was developed. The model was
implemented in a circuit simulation...