Sensitivity and 3 dB Bandwidth in Single and Series-Connected Tunneling Magnetoresistive Sensors.
As single tunneling magnetoresistive (TMR) sensor performance in modern high-speed applications is limited by breakdown voltage and saturation of the sensitivity, for higher voltage applications (i.e., compatible to 1.8 V, 3.3 V or 5 V standards) practically only a series connection can be applied. Thus, in this study we focused on sensitivity, 3 dB bandwidth and sensitivity-bandwidth product (SBP) dependence on the DC bias voltage in single and series-connected TMR sensors. We show that, below breakdown voltage, the strong bias influence on sensitivity and the 3 dB frequency of a single sensor results in higher SBP than in a series connection. However, the sensitivity saturation limits the single sensor SBP which, under 1 V, reaches the same level of 2000 MHz∙V/T as in a series connection. Above the single sensor breakdown voltage, linear sensitivity dependence on the bias and the constant 3 dB bandwidth of the series connection enable increasing its SBP up to nearly 10,000 MHz∙V/T under 5 V. Thus, although by tuning bias voltage it is possible to control the sensitivity-bandwidth product, the choice between the single TMR sensor and the series connection is crucial for the optimal performance in the high frequency range.
Department of Electronics, AGH University of Science and Technology, Krakow 30-059, Poland. mchdbk@agh.edu.pl.|Silicon Creations, 49 Highway 23 NE, Suwanee 30024, GA, USA. mchdbk@agh.edu.pl.
Michał
M
Dąbek
Department of Electronics, AGH University of Science and Technology, Krakow 30-059, Poland. piotr.wisniowski@agh.edu.pl.
Piotr
P
Wiśniowski
Department of Electronics, AGH University of Science and Technology, Krakow 30-059, Poland. stobieck@agh.edu.pl.
Tomasz
T
Stobiecki
Singulus Technologies AG, Kahl am Main 63796, Germany. jerzy.wrona@singulus.de.
Jerzy
J
Wrona
INESC-MN and IN, Lisbon 1000-029, Portugal. scardoso@inesc-mn.pt.|Physics Department, Instituto Superior Tecnico, Universidade de Lisboa, Lisbon 1600-276, Portugal. scardoso@inesc-mn.pt.
Susana
S
Cardoso
INESC-MN and IN, Lisbon 1000-029, Portugal. paulo.freitas@inl.int.|Physics Department, Instituto Superior Tecnico, Universidade de Lisboa, Lisbon 1600-276, Portugal. paulo.freitas@inl.int.|INL-International Iberian Nanotechnology Laboratory, Avenida Mestre José Veiga s/n, Braga 4715-330, Portugal. paulo.freitas@inl.int.
Paulo P
PP
Freitas
current sensors; high-speed electronics; magnetoresistive sensors; sensitivity-bandwidth product; tunneling magnetoresistance