Magnetic Field Sensors
KMY 20 M
Function principle
Magnetoresistive materials can change their resistivity in an external magnetic field. The
variation of the resistivity is determined by the rotation of magnetisation with respect to the
direction of the current flow. Permalloy (Ni Fe ) is commercially used as
81 19
magnetoresistive material. The relative change of resistivity is 2-3 % for this material. The
high sensitive and small size magnetoresistive sensor consists of the chip 174B coated
with thin film permalloy stripes. These stripes form a Wheatstone bridge, whose output
voltage is proportional to the magnetic field component H .
y
Characteristic
The bridge imbalance is a value for the magnetic field component H in the plane of the
y
chip. It is of advantage to apply an auxiliary field H = 3 kA/m which avoids flipping of the
x
magnetisation of the stripes caused by disturbing magnetic fields. A perpendicular field H
x
is necessary to stabilize sensor operation. This can be done by using a small permanent
magnet. Magnetic fields vertical to the chip surface have no influence on the output
voltage.
Special feature
In contrast to KMY 20 S, sensor KMY 20 M features a permanent magnet integrated in the
housing. The compact sensor is ready to use. No external auxillary fields are required for
safe operation in a disturbing field up to 30 kA/m.
Sensors in thin film technology
HL-Planartechnik GmbH
Hauert 13, D - 44 227 Dortmund, Tel.: +49 (0) 231/97400, Fax.: +49 (0) 231/974020
Internet: http://www.hlplanar.com E-Mail: service@hlplanar.deMagnetic Field Sensors
KMY 20 M
Technical data
Applications
Absolute maximum ratings
- detection of weak magnetic fields,
e.g. earth magnetic field
Parameter Symbol Unit Value
- contactless mechanical switch
- displacement measurement with
Supply voltage VB V 12 high resolution
Total power dissipation Pto mW 120 - revolution speed detection
Operating temperature range Tamb °C -40 ... + 125 on ferromagnetic gear wheels
Storage temperature range Tstg °C -65 ... +150 - contactless angle measurement
Disturbing field Hd kA/m ≤ 30 - mga el ava sun ric ea mll ey ns te perated current
Electrical characteristics (T = 25°C)
amb
U
0
[mV/V]
H x = 3 kA/m
Parameter Symbol Unit Value 8
6
B Or pid eg ne c r ire cs uis itt a sn ec ne s itivity R SB V (mV/V)/(k kO A/h mm ) 51 .. 54 ±.. 12 .. 52 4 H x = 1 kA/m
Output voltage range ?VO /VB mV/V 18.0 ± 4.0 2
Hysteresis of output voltage VO H /VB μV/V ≤ 50
Offset voltage VOFF /VB mV/V ≤ ± 1.5 -4 -3 -2 -1 1 2 3 H y [kA/4 m]
Permanent auxiliary field Hx kA/m 1.5 ± 0.4 -2
-4
Temperature coefficients ( - 25 °C < T < 125 °C)
amb -6
of
-8
Parameter Symbol Unit Value
Output voltage versus field component Hy
Bridge resistance TCBR %/K 0.30 ± 0.05 for different stabilizing magnetic fields Hx
Open circuit sensitivity
(VB = const) TCSV %/K -0.25 ± 0.05
(IB = const) TCSI %/K 0.05 ± 0.05
Offset voltage TCOFF (μV/V)/K ≤ ± 3
Difference of offset voltage ?TCOFF (μV/V)/K ≤ ± 0.5
for sensor pair
Hausing KMY 20: SOT-223-S
2 KMY 20 M
We also offer selected
pairs of KMY 20 M.
These pairs have a
similar temperature
characteristic of the
voltage offset and are
well suited for differential
measuring techniques.
The temperature drift of
the magnetoresistive
sensor is strongly
reduced by applying this
technique.
SOT-223-S
1: +V0 2: -V0 V0: Ausgangsspannung
metrische Dimensionen 3: +VΒ 4: -VB VB: Betriebsspannung
Sensors in thin film technology
HL-Planartechnik GmbH
Hauert 13, D - 44 227 Dortmund, Tel.: +49 (0) 231/97400, Fax.: +49 (0) 231/974020
Internet: http://www.hlplanar.com E-Mail: service@hlplanar.de 7.12.01

KMY 20M是一款磁阻傳感器，其中"M"通常代表Metal-Oxide-Semiconductor (金屬氧化物半導(dǎo)體) 磁阻效應(yīng)，這是一種利用材料（如金屬或合金）電阻率隨磁場(chǎng)變化特性來檢測(cè)磁場(chǎng)強(qiáng)度的技術(shù)。在這款具體型號(hào)中，"KMY"可能是生產(chǎn)廠商、產(chǎn)品系列或者商標(biāo)的縮寫，而"20M"可能表示該磁阻傳感器的工作頻率范圍、測(cè)量精度等級(jí)或者是最大允許工作電流等規(guī)格參數(shù)中的某一項(xiàng)。 作為一款磁阻傳感器，KMY 20M廣泛應(yīng)用于各種需要高精度磁場(chǎng)檢測(cè)的場(chǎng)合，例如電機(jī)控制、位置反饋、速度和轉(zhuǎn)速監(jiān)測(cè)、車輛防抱死制動(dòng)系統(tǒng)(ABS)、工業(yè)自動(dòng)化設(shè)備以及家用電器等領(lǐng)域。它通過非接觸方式感應(yīng)磁場(chǎng)，具有響應(yīng)速度快、抗干擾性能好以及線性度高等優(yōu)點(diǎn)。用戶在使用時(shí)需要按照相應(yīng)的數(shù)據(jù)手冊(cè)進(jìn)行接線與參數(shù)設(shè)置，并確保工作環(huán)境符合其額定條件。