Diodes ZMT32 User Manual

ZMT32

()

()

α

α

α

2

2

2

1

2

Tan

Cos

Sin

V

V

O

O

==

-VO1(cos)

-V

O2

(sin)

V

CC2

(bridge 2)

V

CC1

(bridge 1)

+V

O1

(cos)

+V

O2

(sin)

GND2 (bridge 2)

GND (bridge 1)

2

3

4

5

6

7

8

1

Magnetic Field Angle Sensor

Description

The ZMT32 is a thin film permalloy magnetic
field sensor, which contains two galvanic
isolated Wheatstone Bridges for high
precision angle measurement applications
under low field conditions. This angle sensor
is based on the anisotropic magnetoresistive
effect (AMR). The two internal (V

CC1

, V

CC2

bridges enclose a relative sensitive angle of
45 degrees. The input field is a rotating
magnetic field in the chip plane (parallel to
the surface of package). This rotating field will
make available two independent sinusoidal
output signals with the following relationship

()

where α = angle between sensor axis and field

direction

The precise ZMT32 works with low field
applications (H
than similar devices. The ultimate output signal
quality depends on the external magnetic
material and on the mechanical realization.

)

The ZMT32 is a passive part and the Arc­Tangent interpolation needs external signal
processing. Typical areas of application are
angle and speed measurement.

= 8 to 25kA/m), much lower

rot

Features

• contactless angle measurement up to 180°

• flexible measuring solutions for moved
systems

• stable operation over long time

• high temperature range up to +160°C

Applications

• angle and angular velocity measuring systems

• absolute angle and angle change

• automotive electronic (steering, throttle
control, pedal positioning, etc

• contactless rotary switches and potentiometer

• automatic adjustment

Ordering Information

Device Reel size

(Inches)

ZMT32TA 7 12 1,000 ZETEX

Tape w idt h

(mm)

Quantity

per reel

Device

marking

ZMT32

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© Zetex Semiconductors plc 2008

ZMT32

Absolute maximum ratings

Parameter Symbol Limit Unit

Supply Voltages V

Single Bridge Current I

Operating Temperature

T

cc1

cc1

A

and V

or I

cc2

cc2

10 V

4 mA

-40 to +160 °C

Range

Storage Temperature

T

-55 to +175 °C

stg

Range

Recommended operating conditions

Symbol Parameter Min Typ Max Unit

V

, V

cc1

cc2

H

rot

Supply Voltages 5 8.5 V

Applied Magnetic Field Strength 8 25 kA/m

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© Zetex Semiconductors plc 2008

Electrical characteristics

NOTES:

%100

)T(

V

V

)T(

V

V

)T(

V

V

TT

1

TCV

0

CC

O

1

CC

O

2

CC

O

12

O

×

Δ

Δ

−

Δ

×

−

=

)T(

V

V

n

CC

O

Δ

General test conditions (unless otherwise noted)

TA= +23±5oC, V

CC1=VCC2

= +5V, H

ROT

=25kA/m

SYMBOL PARAMETER CONDITIONS MIN

Sα1 or S

V

PO1

or V

Sensitivities (zero crossing)

α2

Peak Output Voltages

PO2

(sinusoidal signals)

k Amplitude bridge matching 99.77 100 100.23 %

Temperature coefficient of
amplitude bridge matching

Bridge resistances

B

TC of Bridge Resistances +0.28 +0.32 +0.36 %/K

B

A

Peak to peak output swing

A

TC of peak to peak output

B

O

swing

A

CC1

Output offset voltage

A

CC2

B

TC of output offset voltage -4 0 +4 µV/V/K

A

Angular Inaccuracy 0.05 0.2 deg

A

Angular hysteresis

Isolation Bridge Current

TCR

∆V

O1/VCC1

∆V

O2/VCC2

TCV

V

OFF1

V

OFF2

TCV

TCk

R

B1

or

R

B2

or

or

∆α

∆αH

I

iso1-2

/V

/V

OFF

(†)

, k=100•(V

α1=135°, α2=0°

TA = -40 to +160°C

no H

ROT

H

= 8 kA/m

ROT

H

= 8 kA/m

ROT

no H

ROT

H

ROT

no H

PO1/VPO2

TA = -40°C

TA = 23°C

TA = +160°C

TA = -40°C

TA = 23°C

TA = +160°C

(†)

T

TA = -40°C

TA = +160°C

(†)

T

= 8 kA/m

ROT

= 23°C

A

= 23°C

A

(†)

) with V

CC1=VCC2

TYP

(*)

0.35 mV/V/deg

40 50 60 mV

-0.008 +0.008 %/K

2017 3040

2500 3000 3600

3345 5114

19.2 30.4

16 20 24

6.7 13.4

16 20 24

-0.35 -0.32 -0.28 %/K

-1.25 +1.25

-1.55 +1.55

-1 0 +1

-2 0 +2

00.1µA

ZMT32

MAX UNIT

Ω

mV/V

mV/V

0.1 deg

0.5

(‡)

deg

(*) Typical values apply to an ambient temperature of 23oC

(†) See point “Magnetic Field Tests” below

(‡) The accurate control of this parameter (Lim

=0.1deg, H

max

=25kA/m) takes place by means of sample tests

ROT

A: Output characteristic definitions

∆VO1/V

V

OFF1/VCC1

∆αH = MAX | α
∆α = MAX | α

CC1

= (V

= ½(V

o

– V

OMAX1

OMAX1

LEFT TURN

OMIN1

+ V

OMIN1

– α

RIGHT TURN

)/V

or/ ∆VO2/V

CC1

)/V

or/ V

CC1

= (V

CC2

OFF2/VCC2

OMAX2

= ½(V

– V

OMAX2

OMIN2

+ V

)/V

CC2

OMIN2

)/V

| (max. angular difference between left and right turn)

CC2

– α | (max. angular difference between actual value αoand measured angle,

without offset error)

B: Temperature coefficient (TC) equations

T1 = -25°C, T0 = +25°C, T2 = +125°C

where

is the peak-peak output voltage at temperature T

n

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