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

2. 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

3. 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

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

5. 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.

6. Type T-H3A Hall Probe

7. 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

8. 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

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

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

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

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

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

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

15. Block diagram of the integrated Hall probe

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

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

18. 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

19. 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)

20. 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

21. 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

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

23. 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)

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

25. SENIS GmbH
Technoparkstrasse 1
CH-8005 Zurich