Siemens TLE4923 Datasheet

Dynamic Differential Hall Effect Sensor IC TLE 4923

Bipolar IC

Features

• Advanced performance

• Higher sensitivity

• Symmetrical thresholds

• High piezo resistivity

• Reduced power consumption

• South and north pole pre-induction possible

• AC coupled

• Digital output signal

• Two-wire interface

• Large temperature range

• Large airgap

• Low cut-off frequency

• Protection against reversed polarity

P-SSO-3-6

Type Ordering Code Package

▼ TLE 4923 Q62705-K408 P-SSO-3-6
▼ New type

The differential Hall effec t sensor TLE 4923 is compatible to the TLE 4921-3U, except
for having a 2-wire interface. The TLE 4923 provides high sensitivity, a superior stability
over temperature and symme trical thresholds in order to achieve a s table duty cycle.
TLE 4923 is particularly suitable for rotational speed detection and timing applications of
ferromagnetic toothed wheels such as in anti-lock braking systems, transmissions,
crankshafts, etc. The integrate d circuit (based on Hall effect) provides a dig ital 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.

Semiconductor Group 1 1998-04-29

Pin Configuration

(top view)

1.53

2.67

TLE 4923

Center of

sensitive area ± 0.15

2.5
231

V

GND

S

C

AEP02039

Figure 1

Pin Definitions and Functions
Pin No. Symbol Function

1

V

S

Supply voltage
2 GND Ground
3

C

Capacitor

Semiconductor Group 2 1998-04-29

TLE 4923

Protection

Device

1

V

S

Hall-Probes

Figure 2 Block Diagram

2

GND

Internal Reference and Supply

V

(3V)

reg

Highpass-

Amplifier

Filter

C

F

Schmitt-

Trigger

3

AEB01896

Semiconductor Group 3 1998-04-29

TLE 4923

Functional Description

The Differential Hall sensor IC detects the motion and position of ferromagnetic and
permanent magnet structure s by mea suring the dif feren tial flux density of the mag netic
field. To detect ferromagne tic 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 cap acitor the gene rated Hall vo ltage signal is slowly adju sted via an
active high pass filter with low frequency cut-off. This causes the output to switch in to a
biased mode after a time constant is e lapsed. The time constant is determi ned by the
external capacitor. Filtering avoids aging and temperature influence from Schmitt-trigger
input and eliminates device and magnetic offset.

The TLE 4923 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.

The on and off state of the IC are indicated by high and low current consumption.

Circuit Description (see Figure 2)

The TLE 4923 is comprised of a supply voltage referenc e, a pair of Hall probes sp ace d
at 2.5 mm, differential amplifier, filter for offset compensation, Schmitt-trigger, and a
switched current source.

The TLE 4923 was designed to have a wide range of application parameter
variations. Differential fields up to ± 40 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

1)

not influence the switching points

. The improved temperature compensation
enables a superior sensitivity and accuracy over the tempera ture 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 reverse polarity.

1)

Differential bias fields exceeding ± 20 mT, e. g. caused by a mis aligned magnet, should be avoided.

Semiconductor Group 4 1998-04-29

TLE 4923

Absolute Maximum Ratings
Parameter Symbol Limit Values Unit Remarks

min. max.

Supply voltage

V

S

– 18

1)

24 V
Capacitor voltage
Junction temperature

Junction temperature
Junction temperature
Junction temperature

Storage temperature
Thermal resistance

1)

Reverse current drawn by the d ev ic e < 10 mA

2)

Can be reduced significant ly by f urt her packaging process, e. g. overm olding.

The device is ESD protected up t o 2 kV (HL test proc edure)

V
T

T
T
T

T
R

C

j
j
j
j

S

th JA

– 0.3 3 V

150

160

170

190

°C
°C
°C
°C

– 40 150 °C

190 K/W

5000 h
2500 h
500 h
4h

2)

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

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

Operating Range
Parameter Symbol Limit Values Unit Remarks

min. max.

Supply voltage
Junction temperature
Pre-induction

V
T
B

S

j

0

4.5 18 V
– 40 190 °C
– 500 500 mT At Hall probe;

independent of
magnet
orientation

Differential induction ∆

B – 40 40 mT

Note: Unless otherwise noted, all temperatures refer to junction temperature.

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

Semiconductor Group 5 1998-04-29

TLE 4923

AC/DC Characteristics

The device characteristics listed below are guaranteed in the full operating range.

Parameter Symbol Limit Values Unit Test Condition Test

min. typ. max.

Circuit

Supply current

Supply current
difference

Supply current ratio

Center of switching
points:

B

(∆

+ ∆BRP) / 2

OP

Center of switching
points:

B

(∆

+ ∆BRP) / 2

OP

Hysteresis ∆

Current rise time

I

S

I

son

I

SON

I

SOFF

∆

B

∆

B

B

t

r

m

m

hy

- I

3.1

8.1

5.0 6.4 8.3 mA 1

soff

/

22.43 1

4.1

10.5

5.3

13.6

mA
mA

– 0.5 0 0.5 mT ∆B = 2.0 mT,

f = 200 Hz,

T

1) 2)

≤

j

– 40 °C<
150 °C

– 0.7 0 0.7 mT ∆B = 2.0 mT,

f = 200 Hz,

T

1) 2)

<

j

3)

150 °C<
190 °C

11.52.2mT∆B = 2.0 mT,

f = 200 Hz

0.5 µs2

1
1

2

2

2

Current fall time
Delay time

4)

Filter input resistance
Filter sensitivity to ∆

BS

Filter bias voltage
Frequency
Resistivity against

mechanical stress
(piezo)

6)

t

f

t

dop

t

drp

t

dop

R

C

V
f

∆B
∆B

0.5 µs2
25

10

- t

drp

C

35 43 52 kΩ 25 °C ± 2 °C1

15

µs
µs
µs

f = 10 kHz,

B = 5 mT

∆

2

8.5 mV/mT25 °C ± 2 °C1

C

m
Hy

1.6 2.0 2.4 V ∆B = 0 1

5)

– 0.1
– 0.1

10000 Hz ∆B = 5 mT 2

0.1

0.1

mT
mT

F = 2 N 2

Semiconductor Group 6 1998-04-29