A 237 ppm/°C L-Band Active Inductance Based Voltage Controlled Oscillator in SOI 0.18 µm

Abstract

Multi-frequency receivers have become a standard for Global Navigation Satellite Systems ( GNSS ) and Global Positioning Systems ( GPS ) applications. In smart vehicle applications, multi-frequency receivers need to work reliably in a large temperature variation. Even though literature has presented solutions for frequency stability over temperature, they usually rely on external control circuits or non-silicon solutions such as wide-bandgap materials or MEMS resonators, leading to higher production costs. This work proposes a temperatureaware design of an active-inductor-based, MOSFET only, voltagecontrolled oscillator suitable for the L-Band. The temperature analysis is made based on a gm/ID methodology for the transistor biasing and MOSFET capacitors. Those analyses are validated from simulation models (-40 • C to 175 • C) and transistor measurements up to 200 • C. Monte-Carlo post-layout simulations present a mean first-order temperature coefficient of 237 ppm/ • C and cover the entire L-Band.

A General gm/Id Temperature-Aware Design Methodology Using 180 nm CMOS up to 250 °C

“…Those parameters were obtained from measurement data from 27 • C to 300 • C. However, no ZTC point was exploited, nor were analytical expressions for the different g m /I D temperature behaviors discussed. This paper extends the proposals of [15,16] in a general temperature-aware framework using the g m /I D methodology. This work introduces two new parameters G g and G d that are so-called "temperature normalized g m /I D parameters" validated from -40 • C to 175 • C using simulations and measurement data of from XT018 a 0.18 µm node from X-FAB.…”

“…The existence of ZTC points is not limited to transistors small signal parameters. In [16] new ZTC points for the transistor total gate capacitance and gate to source capacitance (C gg , C gs ) were also proposed. Figure 3 illustrates the total gate capacitance temperature sensitivity extracted from measurement data from 27 • C to 175 • C. It is noticeable that the temperature behavior at depletion and inversion follows closely the G g temperature sensitivity illustrated on Fig.…”

“…This paper extends the proposition of [15] presenting new measurement data for transistors at 225 • C and 250 • C, showing a possible general recipe for making a temperatureaware circuit and introducing a new tool for temperature analysis on integrated circuits. The presented recipe is then applied for the VCO circuit presented at [16] obtaining the same results with a more general framework the one proposed on [15]. This brief is organized as follows.…”

“…It is important to highlight that even though higher temperatures are explored in research, producing an industrial node for temperatures higher than 175 • C are limited by the back end of line (BEOL). The methodology was used to design an OTA with temperature-stable differential gain [15] and a Voltage Controlled Oscillator [16]. However, no straightforward indications are given for generic circuits.…”

“…Section III uses the previously developed temperature models and generalizes their usage in an analog circuit. Section IV applies the technique in the VCO presented in [16] and Section V concludes and summarizes this brief.…”