Analog Sinewave Signal Generators for Mixed-Signal Built-in Test Applications

Abstract

This work presents a technique for the generation of analog sinusoidal signals with high spectral quality and reduced circuitry resources. Two integrated demonstrators are presented to show the feasibility of the approach. The proposed generation technique is based on a modified analog filter that provides a sinusoidal output as the response to a DC input. It has the attributes of digital programming and control, low area overhead, and low design effort, which make this approach very suitable as test stimulus generator for built-in test applications. The demonstrators-a continuous-time generator and a discrete-time one-have been integrated in a standard 0.35µm CMOS technology. Simulation results and experimental measurements in the lab are provided, and the obtained performance is compared to current state-of-the-art on-chip generation strategies.

On-chip sinusoidal signal generation with harmonic cancelation for analog and mixed-signal BIST applications

“…1: closed-loop generators, which consists of a filtering section with a nonlinear feedback mechanism [1,4,12], and open-loop generators, which are based on a digital pattern generator followed by a D/A conversion and a filtering stage [2,5,14].…”

“…However, moving the technique to an on-chip implementation may be problematic due to the extensive use of analog processing, which would demand large on-chip resources and power consumption. As an alternative, the technique presented by the authors in [3] makes use of a similar harmonic cancellation strategy, but instead of employing an oscillator, we propose to use the efficient methodology for sine-wave generation presented in [2]. This generation technique is based on a low-order modified analog filter with a DC input and programmable input elements, in such a way that the filter performs signal generation and filtering of the unwanted spectral components at the same time.…”

“…2 are used to provide p = (n − 1)/2 pairs of signals of opposite delays, ∆t i and −∆t i , respect to signal x 1 (t). From equations (1), (2), and (3) it can be derived,…”

“…Selecting properly the impulse response h(t) and the number of programmable levels in f (t), it has been proved that this strategy can be used to implement efficient and precise sinusoidal generators [2]. In particular, in [2] we shown that low-pass filter stages are very convenient for this application, given that the main harmonic component in f (t) is placed in the passband, and the rest of undesired components in the rejection band of the filter.…”

“…In particular, in [2] we shown that low-pass filter stages are very convenient for this application, given that the main harmonic component in f (t) is placed in the passband, and the rest of undesired components in the rejection band of the filter. However, the linearity of the generated signal depends on the accuracy of the programmable sine-weighted input levels: in general, these weights are non-integer real numbers, but their implementation is naturally limited by the fabrication process resolution.…”