SENIS 3-Axis Digital Teslameter SENIS GmbH Technoparkstrasse 1 CH-8005 Zurich www.senis.ch SENIS

Structure of a Teslameter Digital Module Computer 0.129 T RS 232 Connector CoH Module H Cable CaH Hall Probe Module E Output Cable Voltmeter Module H Module E +/- 12V Power Supply

All measures are in millimeters (mm). Module H: Hall Probe 1.0 14.5 50 Thin wires 4.0 50 mm 2.0 < 2 Y X Z 1.1 CaH All measures are in millimeters (mm). 5

Probe with a window Visible sensitive point High-accuracy positioning High-accuracy mapping of magnetic fields

Hall Probe Package C-H3A Position accuracy of the field sensitive volume: +/- 0.1 mm Angular accuracy of the axes: +/- 0.5° to the surface.

Type T-H3A Hall Probe

Type T-H3A Hall Probe X FSV Z Y 3000um X 150um 640um Z 150um 20um Y 0.64 12mm 50 Thin wires 4 12 2 < 2 5 Y Z X 2mm 3 FSV 0.55 mm 50 3000um 150um X 640um 150um 20um 550um Z Y

Integrated 3-Axes Hall Probe Chip Front-end electronics Sensing part Driving part Read-out electronics and buffers Bonding connections 200µm Dimensions: 4300 µm x 640 µm x 550 µm

Integrated Planar Hall Element Sensitive to perpendicular field component B CMOS Technology: N-Well Depletion Layer Isolation

Integrated Vertical Hall Element Sensitive to in-plane field component B CMOS Technology: N-Well Depletion Layer Isolation

Planar Hall Effect B Bp Bn I α Vp ∞ I B sin2α 2

MR Model of the Planar Hall effect B ΔR MR long. MR trans. “Voff” ≡ ∞ 2 Vp I R

Orthogonal Coupling of Hall Elements Reducing Offset: Orthogonal Coupling of Hall Elements 2I0 1 2 VH1 = VH2 Vout = VH

Reducing Offset and 1/f Noise « Switched Hall » or « Spinning Current » Technique

Block diagram of the integrated Hall probe

Structure of a Teslameter Digital Module Computer 0.129 T RS 232 Module H Module E

E-Module: inside Temp.Comp of Sens. Offset Comp. Nonlinearity Comp. Hall probe Sensitivity adjust Temperature conditioning

Analogue Signal Treatment Module H Module E Temp. Comp. of SENSITIVITY VINPOS Cs (T) * X VINNEG Pr_Z SENSITIVITY Adjust. Pr_Y 3D IC Hall Probe Pr_X X Out_X+ Input Amplifier Output Amplifier Pr_T Out_X- 2.5V Cnl (B)*X3 Output Conditioning -2.5V OFFSET Comp. (20 °C) NONLINEARITY Comp. Vpt Dif. Amp. Ct *(T-293K) VINPOS xCt Vpt(20°C) invertor +/- Ct *(T-293K) VINNEG Temp. Comp. of OFFSET

Cancellation of Residual Offset (1) Vx Voff_20 + Ct *(T-293K) Voff_20 Ct *(T-293K) Voff_Out T B = 0 20°C - Ct *(T-293K) (From Temperature Sensor)

Cancellation of Residual Offset (2): Block Diagram Input Amplifier OFFSET Comp. (20 °C) 2.5V -2.5V Vpt(20°C) Vpt Dif. Amp. Ct *(T-293K) xCt invertor VINPOS VINNEG X Temp. Comp. of OFFSET Pr_X 3D IC Hall Probe Pr_Z Pr_Y Pr_T - Ct *(T-293K) Vx + Voff_20 + Ct *(T-293K) Vx + Ct *(T-293K) Vx B = 0

Analogue Teslameter Specifications Full scale (nominal) ± 2 T Output voltages differential Sensitivity to d.c. magnetic field 5 V/T (0.5mV/G) Tolerances of sensitivity (B = 1T d.c ) < ± 0.1 % Temp. coefficient of sensitivity < 100 ppm /°C Non-linearity of output (B <= 2T) < 0.05 % Planar Hall effect: Vplan / Vvert (B = 1T) < 0.01% Long-term instability of sensitivity < 1 % over 10 years Offset (B = 0T) < ± 1 mV (0.2mT) Temp. coefficient of offset < (0.02mT/°C) Temperature out: [T(°C)-(23°C ±0.5°C)]x500mV/°C

Structure of a Teslameter Digital Module Computer 0.129 T RS 232 Module H Module E

Digital Module: Functions 16 bit A/D Conversions of signals from E-Module Calibration accuracy: up to 0.01% Digital display of Bx, By, Bz Fast RS232 interface(115200bps)

Teslameter - User Interface Digital Module Computer Load/Save calibration data Measurement Mode Graph setup Plot Measurement data on screen Serial interface

SENIS GmbH Technoparkstrasse 1 CH-8005 Zurich www.senis.ch