Strategies for built-in characterization testing and performance monitoring of analog RF circuits with temperature measurements

Abstract

This paper presents two approaches to characterize RF circuits with built-in differential temperature measurements, namely the homodyne and heterodyne methods. Both non-invasive methods are analyzed theoretically and discussed with regard to the respective trade-offs associated with practical off-chip methodologies as well as on-chip measurement scenarios. Strategies are defined to extract the center frequency and 1 dB compression point of a narrow-band LNA operating around 1 GHz. The proposed techniques are experimentally demonstrated using a compact and efficient on-chip temperature sensor for built-in test purposes that has a power consumption of 15 μW and a layout area of 0.005 mm 2 in a 0.25 μm CMOS technology. Validating results from off-chip interferometer-based temperature measurements and conventional electrical characterization results are compared with the on-chip measurements, showing the capability of the techniques to estimate the center frequency and 1 dB compression point of the LNA with errors of approximately 6% and 0.5 dB, respectively.

Electro-thermal coupling analysis methodology for RF circuits

“…In this situation, the lowfrequency power dissipation generates AC temperature signals at frequency multiples of 25kHz that affect the dynamic electrical behaviour of the blocks on the chip. This circumstance is also reported in [8]. In this work, RF circuits (1GHz) are driven with a two-tone electrical signal in order to generate a temperature increase at the difference of frequencies of the applied signals.…”

“…As the power dissipated at low frequencies depends on the high-frequency electrical signals, the low-frequency temperature increase measurement is used to characterize and to obtain electrical figures of merit of the RF circuit. This fact is utilized in [8] to design a built-in non-invasive mechanism to characterize RF circuit through low-frequency temperature measurements performed by temperature sensors embedded in the same silicon die. In this context, the goal of this paper is to describe a procedure suitable to perform electro-thermal analysis of RF and highfrequency circuits.…”

DC Temperature Measurements to Characterize the Central Frequency and 3 dB Bandwidth in mmW Power Amplifiers

“…A differential temperature sensor was implemented in the same IC and placed close to the last stage of the PA in order to monitor its power dissipation. Details of the sensor circuit and the PA + sensor layout can be seen in [2,3,7]. Fig.…”

“…While f IN was swept from 50 GHz to 67 GHz, the spectral component of the temperature at 5 kHz was monitored by measuring at the output of a built-in thermal sensor. The strategy of using two tones to drive the circuit under test in order to achieve a low frequency temperature increase is known as heterodyne temperature measurement [3].…”

“…To avoid this measurement complexity, an alternative approach known as homodyne temperature measurement uses a single input tone and DC temperature measurement [3]. This strategy has been used before [4][5][6][7] to monitor several other metrics of RF PAs, and in [8] as monitor of the structural integrity (structural test) of a RF LNA, but never used to characterize the frequency response in mmWave amplifiers.…”