Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para a obtenção do grau de Mestre em Engenharia Electrotécnica e de ComputadoresThis thesis proposes a study of three different RC oscillators, two relaxation and a ring oscillator. All the circuits are implemented using UMC 130 nm CMOS technology with a supply voltage of 1.2 V.
We present a wideband MOS current/voltage controlled quadrature oscillator constituted
by two multivibrators. Two different forms of coupling named, soft (traditional)and hard (proposed) are differentiated and investigated. It is found that hard coupling
reduces the quadrature error and results in a low phase-noise (about 2 dB improvement)
with respect to soft coupling. The behaviour of the singular and coupled multivibrators
is investigated, when an external synchronizing harmonic is applied.
We introduce a new RC relaxation oscillator with pulse self biasing, to reduce power
consumption, and with harmonic ltering and resistor feedback, to reduce phase-noise.
The designed circuit has a very low phase-noise, -132.6 dBc/Hz @ 10 MHz offset, and
the power consumption is only 1 mW, which leads to a gure of merit (FOM) of -159.1
dBc/Hz.
The nal circuit is a two integrator fully implemented in CMOS technology, with low
power consumption. The respective layout is made and occupies a total area of5.856x10-3
mm2, post-layout simulation is also done
