P-SSO-4-1

Data Sheet

2000-07-01

Dynamic Differential Hall Effect Sensor IC

TLE 4921-3U

Bipolar IC

The differential Hall Effect sensor TLE 4921-3U provides a high sensitivity and a superior
stability over temperature and symmetrical thresholds in order to achieve a stable duty
cycle. TLE 4921-3U is particularly suitable for rotational speed detection and timing
applications of ferromagnetic toothed wheels such as anti-lock braking systems,
transmissions, crankshafts, etc. The integrated circuit (based on Hall effect) provides a
digital signal output with frequency proportional to the speed of rotation. Unlike other
rotational sensors differential Hall ICs are not influenced by radial vibration within the
effective airgap of the sensor and require no external signal processing.

Type

Marking

Ordering Code

Package

TLE 4921-3U

21C3U

Q67006-A9171

P-SSO-4-1

Features

· Advanced performance
· High sensitivity
· Symmetrical thresholds
· High piezo resistivity
· Reduced power consumption
· South and north pole pre-induction possible
· AC coupled
· Digital output signal
· Two-wire and three-wire configuration possible
· Large temperature range
· Large airgap
· Low cut-off frequency
· Protection against overvoltage
· Protection against reversed polarity
· Output protection against electrical disturbances

TLE 4921-3U

Data Sheet

2000-07-01

Functional Description

The Differential Hall Sensor IC detects the motion and position of ferromagnetic and
permanent magnet structures by measuring the differential flux density of the magnetic
field. To detect ferromagnetic objects the magnetic field must be provided by a back
biasing permanent magnet (south or north pole of the magnet attached to the rear
unmarked side of the IC package).

Using an external capacitor the generated Hall voltage signal is slowly adjusted via an
active high pass filter with a low cut-off frequency. This causes the output to switch into
a biased mode after a time constant is elapsed. The time constant is determined by the
external capacitor. Filtering avoids aging and temperature influence from Schmitt-trigger
input and eliminates device and magnetic offset.

The TLE 4921-3U can be exploited to detect toothed wheel rotation in a rough
environment. Jolts against the toothed wheel and ripple have no influence on the output
signal.

Furthermore, the TLE 4921-3U can be operated in a two-wire as well as in a three-wire-
configuration.

The output is logic compatible by high/low levels regarding on and off.

Circuit Description (see Figure 2)

The TLE 4921-3U is comprised of a supply voltage reference, a pair of Hall probes
spaced at 2.5 mm, differential amplifier, filter for offset compensation, Schmitt trigger,
and an open collector output.

The TLE 4921-3U was designed to have a wide range of application parameter
variations. Differential fields up to

80 mT can be detected without influence to

the switching performance. The pre-induction field can either come from a
magnetic south or north pole, whereby the field strength up to 500 mT or more will
not influence the switching points. The improved temperature compensation
enables a superior sensitivity and accuracy over the temperature range. Finally
the

optimized

piezo

compensation

and

the

integrated

dynamic

offset

compensation enable easy manufacturing and elimination of magnet offsets.

Protection is provided at the input/supply (pin 1) for overvoltage and reverse polarity and
against overstress such as load dump, etc., in accordance with ISO-TR 7637 and
DIN 40839. The output (pin 2) is protected against voltage peaks and electrical
disturbances.

TLE 4921-3U

Data Sheet

2000-07-01

Note: Stresses above those listed here may cause permanent damage to the device.

Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.

Absolute Maximum Ratings

= 40 to 150

Parameter

Symbol

Limit Values

Unit

Remarks

min.

max.

Supply voltage

Output voltage

0.7

Output current

Output reverse current

Capacitor voltage

0.3

Junction temperature
Junction temperature
Junction temperature
Junction temperature

150
160
170
210

5000 h
2500 h
1000 h
40 h

Storage temperature

150

Thermal resistance
P-SSO-4-1

th JA

190

K/W

Current through input-
protection device
Current through output-
protection device

200

< 2 ms;

= 0.1

< 2 ms;

= 0.1

Electro Magnetic Compatibility

ref. DIN 40839 part 1; test circuit 1

Testpulse 1
Testpulse 2
Testpulse 3a
Testpulse 3b
Testpulse 4
Testpulse 5

100

150

100

120

V
V
V
V
V
V

= 2 ms

= 0.05 ms

= 0.1

20 s

= 400 ms;

= 400

Reverse current < 10 mA

TLE 4921-3U

Data Sheet

2000-07-01

Note: In the operating range the functions given in the circuit description are fulfilled.

Operating Range

Parameter

Symbol

Limit Values

Unit

Remarks

min.

max.

Supply voltage

4.5

Junction temperature

170

Pre-induction

500

at Hall probe;
independent of
magnet orientation

Differential induction

AC/DC Characteristics

Parameter

Symbol

Limit Values

Unit Test Condition

Test
Circuit

min.

typ.

max.

Supply current

4.7

5.1

6.1

6.7

8.0

8.8

= high

= 0 mA

= low

= 40 mA

Output saturation
voltage

QSat

0.25 0.6

= 40 mA

Output leakage
current

= 24 V

Center of
switching points:
(

) / 2

 1

 20 mT <

20 mT

1) 2)

200 Hz

Operate point

= 200 Hz,

= 20 mT

Release point

= 200 Hz,

= 20 mT

Hysteresis

0.5

1.5

2.5

200 Hz,

= 20 mT

Overvoltage
protection at supply
voltage at output

27
27

35
35

V
V

= 16 mA

1
1

Output rise time

0.5

= 40 mA

= 10 pF

TLE 4921-3U

Data Sheet

2000-07-01

Note: The listed characteristics are ensured over the operating range of the integrated

circuit. Typical characteristics specify mean values expected over the production
spread. If not otherwise specified, typical characteristics apply at

= 25

C and

the given supply voltage.

Output fall time

0.5

= 40 mA

= 10 pF

Delay time

dop

drp

dop

drp

25
10
15

= 10 kHz

= 5 mT

Filter input
resistance

Filter sensitivity to

mV/
mT

Filter bias voltage

0.8

2.2

= 0

Frequency

20000 Hz

= 5 mT

Resistivity against
mechanical stress
(piezo)

0.1
0.1

mT
mT

F = 2 N

Leakage currents at pin 4 should be avoided. The bias shift of

caused by a leakage current

can be

calculated by:

For higher

the values may exceed the limits like following

0.05

For definition see page 16.

Depends on filter capacitor

. The cut-off frequency is given by

. The switching points are

guaranteed over the whole frequency range, but amplitude modification and phase shift due to the 1

order

highpass filter have to be taken into account.

See page 17.

AC/DC Characteristics (cont'd)

Parameter

Symbol

Limit Values

Unit Test Condition

Test
Circuit

min.

typ.

max.

( )

------------------------------

----------------------------------

TLE 4921-3U

Data Sheet

2000-07-01

Application Configurations

Two possible applications are shown in Figure 7 and 8 (Toothed and Magnet Wheel).

The difference between two-wire and three-wire application is shown in Figure 9.

Gear Tooth Sensing

In the case of ferromagnetic toothed wheel application the IC has to be biased by the
south or north pole of a permanent magnet (e.g. SmCO

(Vacuumschmelze VX145) with

the dimensions 8 mm

5 mm

3 mm) which should cover both Hall probes.

The maximum air gap depends on

the magnetic field strength (magnet used; pre-induction) and
the toothed wheel that is used (dimensions, material, etc.; resulting differential field)

Figure 5

Sensor Spacing

Figure 6

Toothed Wheel Dimensions

a centered distance

of Hall probes

b Hall probes to

IC surface

L IC surface to

tooth wheel

= 2.5 mm

= 0.3 mm

AEA01259

AEA01260

Conversion DIN ASA

= 25.4 mm/p

= 25.4 mm CP

DIN

diameter (mm)

number of teeth

module

(mm)

pitch

(mm)

ASA

diameter pitch

(inch)

pitch diameter PD =

(inch)

circular pitch

CP = 1 inch

TLE 4921-3U

Data Sheet

2000-07-01

Figure 9

Application Circuits

AES01263

GND

SIGNAL

Line

Sensor

Mainframe

470 nF

Two-wire-application

R =

330

for example :

120

AES01264

GND

SIGNAL

Line

Sensor

Mainframe

Three-wire-application

470 nF

4.7 nF

for example :

R = 330

330

...

TLE 4921-3U

Data Sheet

2000-07-01

Figure 10 System Operation

AED01697

Missing Tooth

Wheel Profile

Magnetic Field Difference

B = B2-B1

Large Airgap

Small Airgap

HYS

Output Signal

Operate point :
Release point :

B2
B2

HYS

B +

switches the output ON

(

switches the output OFF (

V =

0.75 mT

-0.75 mT

The magnetic field is defined as positive if the south pole of
the magnet shows towards the rear side of the IC housing.

(N)

HIGH)

LOW)

-
- B1

B1 <

N (S)

TLE 4921-3U

Data Sheet

2000-07-01

Quiescent Current versus
Supply Voltage

Quiescent Current Difference
versus Temperature

Quiescent Current versus
Temperature

Quiescent Current versus
Output Current

AED01698

2.5

5.0

7.5

10.0

Q ON

40 mA

S ON

S OFF

AED01700

0.25

0.5

0.75

1.0

Q ON

40 mA

S ON

S OFF

AED01699

-50

2.5

5.0

7.5

10.0

°C

OFF

100

200

S diff

AED01701

2.5

5.0

7.5

10.0

12 V

S ON

TLE 4921-3U

Data Sheet

2000-07-01

Saturation Voltage versus Temperature

Saturation Voltage versus Supply
Voltage

Saturation Voltage versus Output
Current

Switching Points versus Preinduction

AED01702

0.1

0.2

0.3

0.4

-50

4.5 V

50 mA

200

100

°C

AED01704

0.1

0.2

0.3

0.4

40 mA

25 °C

AED01703

-0.4

-50

T = 25 °C

-0.3

-0.2

-0.1

0.1

0.2

0.3

-30

-10

30 mA 50

AED01705

0.5

1.0

1.5

2.0

-500

-250

500

()

typ

B < 80 mT

-80 mT <

TLE 4921-3U

Data Sheet

2000-07-01

Switching Induction versus
Temperature

Minimum Switching Field versus
Frequency

Hysteresis versus Temperature

Minimum Switching Field versus
Frequency

AED01706

-2

-50

100

200

-1

°C

= (

) /2

f = 200 Hz

max

typ

min

AED01708

0.001

0.01

0.1

100

min

C = 940 nF

kHz

0.5

1.0

1.5

2.0

3.0

2.5

25 °C

T = -40 °C

AED01707

-50

100

200

0.5

1.5

2.5

3.5

°C

f = 200 Hz

max

typ

min

AED01709

0.001

0.01

0.1

100

min

C = 940 nF

kHz

3.5

150 °C

T = 170 °C

0.5

1.0

1.5

2.0

2.5

3.0

TLE 4921-3U

Data Sheet

2000-07-01

Delay Time

between Switching Threshold

and Falling Edge of

= 25

Delay Time

versus Differential Field

Delay Time

between Switching Threshold

and Rising Edge of

= 25

Delay Time

versus Temperature

Switching points related to initial measurement
@

= 2 mT,

= 200 Hz

AED01710

dop

kHz

dop

B = 1.2 mT

AED01712

100

f = 10 kHz

d op

d rp

AED01711

drp

kHz

drp

B = 1.2 mT

AED01713

-50

100

200

f = 10 kHz

d op

°C

B = 2 mT

TLE 4921-3U

Data Sheet

2000-07-01

Rise and Fall Time versus Temperature

Capacitor Voltage versus Temperature

Rise and Fall Time versus Output
Current

Switching Thresholds versus
Mechanical Stress

AED01714

-50

100

200

°C

40 mA

100

AED01716

-50

100

200

0.5

1.0

1.5

2.0

3.0

°C

typ

2.5

AED01715

120

25 °C

100

AED01717

0.5

max

min

0.6

0.7

0.8

0.9

1.0

(
-

)

r = 0.5

TLE 4921-3U

Data Sheet

2000-07-01

Filter Sensitivity versus Temperature

Delay Time for Power on (

Switching

from 0 V to 4.5 V)

pon

versus Temp.

Filter Input Resistance versus
Temperature

AED01718

-50

-1

-2

-3

-5

100

200

°C

= 12 V

typ

mV
mT

-4

AED02646

-50

100

200

0.05

0.10

0.15

0.20

0.25

0.35

max

min

0.30

AED01719

-50

100

200

°C

0.5

1.5

max

min

(25 °C)

TLE 4921-3U

Data Sheet

2000-07-01

Package Outlines

5.16

±0.08

0.2

+0.1

-0.1

0.25

0.4

+0.05

3.81

0.6 max.

1 max.

±0.05

±0.3

±0.4

6.35

±0.3

12.7

±1

12.7

38 max.

-0.5

+0.75

±0.5

23.8

-1

±0.5

Adhesive Tape

Tape

0.25

-0.15

±0.1

0.5

±0.5

3.71

±0.08

1x45°

0.15 max.

1.9 max.

1.27

0.2

(0.25)

3.38

±0.06

5.38

±0.05

GPO05357

P-SSO-4-1

(

Plastic Single Small Outline Package

)

Sorts of Packing
Package outlines for tubes, trays etc. are contained in our
Data Book "Package Information".

Dimensions in mm

P-SSO-4-1 : 0.3

d : Distance chip to upper side of IC

±0.08

AEA02712

Hall-Probe

Branded Side

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