Effect of Stress Due to Plastic Package Moisture Absorption in Hall Sensors

Cesaretti, Juan Manuel; Taylor, W.P.; Monreal, G.; Brand, Oliver

doi:10.1109/tmag.2009.2025668

Cited by 25 publications

(12 citation statements)

References 13 publications

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“…Finally, the compensation factor λ is derived considering (9) and an optimal matching between the mechanical stress seen by the Hall plate and by the stress sensor…”

Section: Compensation Of the Piezo-hall Effectmentioning

confidence: 99%

“…Variations of the temperature cause a change of magnetic sensitivity via the temperature dependent mobility and Hall scattering factor [8]. Moreover, a change of the environmental conditions of packaged Hall sensors, i.e., temperature, humidity [9], [10], and cyclic loads [11] lead to a change of the package stress and consequently lead to a change of the sensitivity [5], [12]. An optimized assembly process can help to decrease the stress-related sensitivity drift of Hall sensors [13], [14].…”

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confidence: 99%

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Package Stress Monitor to Compensate for the Piezo-Hall Effect in CMOS Hall Sensors

Huber¹,

Schott²,

Oliver

2013

IEEE Sensors J.

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Package-induced stress changes the sensitivity of planar Hall plates via the piezo-Hall effect. In this paper, we present a novel stress sensor that allows us to compensate for this undesired mechanical cross-sensitivity. The new CMOScompatible sensor is based on a Wheatstone bridge built of eight appropriately arranged n-and p-doped piezoresistors. The differential output signal V bridge of the sensor is proportional to the sum of in-plane normal stresses σ x x +σ yy with the sensitivity S bridge,σ = ∂ V bridge / V bias /∂ σ x x + σ yy = −0.047GPa −1 . Doping concentrations larger than 10 19 cm −3 for both the n-and p-type resistors are used to minimize the parasitic resistor mismatch due to the junction field effect. Simultaneously, the highly doped resistors keep the relative thermal cross-sensitivity of the sensor as small as 74 ppm K −1 . In contrast to conventional sensor rosettes, the new sensor has the advantage of offering a differential output signal. The measured signal is successfully used to decrease the stress-impact on the sensitivity of CMOS Hall sensors by a factor of five.

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“…Finally, the compensation factor λ is derived considering (9) and an optimal matching between the mechanical stress seen by the Hall plate and by the stress sensor…”

Section: Compensation Of the Piezo-hall Effectmentioning

confidence: 99%

mentioning

confidence: 99%

Package Stress Monitor to Compensate for the Piezo-Hall Effect in CMOS Hall Sensors

Huber¹,

Schott²,

Oliver

2013

IEEE Sensors J.

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“…Drifts of electronic circuits due to changes in mechanical stress have been verified in smart Hall sensor circuits [21,22]. For these applications mechanical stress sensors and stress compensation circuits have been developed [23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Compensation of Mechanical Stress-Induced Drift of Bandgap References With On-Chip Stress Sensor

2015

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Today's smart sensor systems rely heavily on bandgap circuit techniques to achieve the required high accuracy. However all presently known bandgap references show a notable lifetime drift of about 1 mV caused by instable mechanical stress in common plastic encapsulated packages. This paper proposes a versatile digital stress compensation scheme which works for arbitrary packages and silicon technologies. It uses a new mechanical stress sensor to measure the sum of inplane normal stress components. The mechanical stress drifts of bandgap reference, stress and temperature sensors were characterized on wafer stripes in a four-point bending fixture. With these results a compensation algorithm was derived. Mechanical stress drifts were provoked by thermal cycling measurements on samples in a QFN-like plastic encapsulated package after moisture soaking. These measurements show that the mechanical stress related drift of a Brokaw bandgap voltage can be reduced by about one order in magnitude over the whole automotive temperature range. Due to the low process spread of the proposed stress sensor only a single-trim at room temperature on wafer level is necessary.

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“…The close spacing of sensor die to current rail, packaging, soldering and moisture swelling of mould compound cause mechanical stress on sensor elements, which affects their gain drift in the order of 2 to 4%. Magnetic feedback could be used to compensate for it [1,2], but consumes relatively high compensation current for the coil. Analog compensation of mechanical stress effects [2] provides a good compensation at much lower additional current consumption, but guarantees optimization only at one temperature.…”

Section: Introductionmentioning

confidence: 99%

“…Magnetic feedback could be used to compensate for it [1,2], but consumes relatively high compensation current for the coil. Analog compensation of mechanical stress effects [2] provides a good compensation at much lower additional current consumption, but guarantees optimization only at one temperature. Digital compensation Figure 1.…”

Section: Introductionmentioning

confidence: 99%

A miniature digital current sensor with differential Hall probes using enhanced chopping techniques and mechanical stress compensation

et al. 2012

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A 10kHz bandwidth 50Amax current sensor using a Hall effect gradiometer without magnetic core provides 80kHz update rate with a digital interface. Very low un-calibrated offset of 30mA (1σ) and after calibration typical 10mA over temperature is accomplished by a chopped multi-bit feedback continuous-time 3rd order ΔΣ-ADC. This also realizes low noise of 13mA rms in 1kHz signal bandwidth. The ADC uses enhanced chopping techniques and additional digital feedback loops to avoid chopper ripple. New analog and digital stresscompensation circuits with lateral and vertical n-doped resistors achieve lifetime gain drifts below 1% and temperature compensation. Auto-zeroing ping-pong comparators offer a fast over-current detection of 1...2µs on a dedicated output pin. The monolithic integrated sensor chip and the 4kV galvanic isolated current rail fit into a very small 7x7x1mm 3 package.

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Effect of Stress Due to Plastic Package Moisture Absorption in Hall Sensors

Cited by 25 publications

References 13 publications

Package Stress Monitor to Compensate for the Piezo-Hall Effect in CMOS Hall Sensors

Package Stress Monitor to Compensate for the Piezo-Hall Effect in CMOS Hall Sensors

Compensation of Mechanical Stress-Induced Drift of Bandgap References With On-Chip Stress Sensor

A miniature digital current sensor with differential Hall probes using enhanced chopping techniques and mechanical stress compensation

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