Classification for synthesis of high spectral purity current-steering mixing-DAC architectures

Abstract

This paper proposes a classification of Mixing-DAC architectures, focusing on spectral purity. Based on literature research, analysis and simulations, the proposed classification shows the impact of architectural choices on the output spectral purity. To concretize the classification and validate the analysis, a number of specific Mixing-DAC architectures are synthesized, discussed and simulated. Given the proposed classification, a set of optimal architectural choices lead to a strong architecture candidate for achieving high spectral purity at high signal frequencies, i.e. SFDR [ 80 dBc at f OUT = 4 GHz for current and future multicarrier GSM applications. The main characteristics of this architecture are: Cartesian signaling, local Gilbert-cell mixing and a fully differential implementation.

Studies on Selected Topics in Radio Frequency Digital-to-Analog Converters

“…2.11 an active implementation of the mixer DAC is shown where the LO signal is applied to the gate of the current source transistor. Different variations on mixing DAC topology combining Gilbert mixer into DAC unit elements has been reported in [36,60,132,19,23,21,22,20,24]. A system-level method to implement a mixing DAC is proposed in Paper V in this thesis, where a discrete-time oscillatory tail current is used in current-steering DAC architecture [103].…”