View TLE4921_1005627.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

Dynamic Differential Hall Effect Sensor IC
TLE 4921-2
Preliminary Data Features
q q q q q q q q
Bipolar IC
AC coupled Digital output signal Two-wire and three-wire configuration possible Large temperature range Large distance, low frequency cut-off Protection against overvoltage Protection against reversed polarity Output protection against electrical disturbances
P-SSO-4-1
Type w TLE 4921-2U w New type
Ordering Code Q67006-A9055
Package P-SSO-4-1
The differential Hall Effect sensor TLE 4921-2U 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.
Semiconductor Group
1
09.94
TLE 4921-2
Pin Configuration (top view)
Pin Definitions and Functions Pin No. 1 2 3 4 Symbol Function Supply voltage Output Ground Capacitor
VS
Q GND
C
Semiconductor Group
2
TLE 4921-2
Figure 1 Block Diagram 1
Semiconductor Group
3
TLE 4921-2
Figure 2 Block Diagram 2 Semiconductor Group 4
TLE 4921-2
Functional Description The Differential Hall Sensor IC detects the motion of, and static 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 (southpole of the magnet attached to the back, 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 low frequency cutoff. 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 4921-2U 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 4921-2U 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 1 and 2) The TLE 4921-2U is comprised of a supply voltage reference, a pair of Hall probes spaced at 2.5 mm, differential amplifier, Schmitt trigger, and open collector output. 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.
Semiconductor Group
5
TLE 4921-2
Absolute Maximum Ratings Tj = - 40 to 150 C Parameter Supply voltage Output voltage Output current Output revers current Capacitor voltage Junction temperature Junction temperature Junction temperature Storage temperature Thermal resistance PSSO-4-1 Current through inputprotection device Current through outputprotection device Symbol Limit Values min. - 40 - 0.7 max. 30 30 50 50 3 150 170 210 150 190 200 - 200 200 Units V V mA mA V C C C C K/W mA mA Remarks
VS VQ IQ - IQ VC Tj Tj Tj Ts Rth JA ISZ IQZ
- 0.3
1000 h 40 h
- 40
t < 2 ms ; v = 0.1 t < 2 ms ; v = 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
VLD VLD VLD VLD VLD VLD
- 100 100 - 150 100 -7 120
V V V V V V
td = 2 ms td = 0.05 ms td = 0.1 s td = 0.1 s td 20 s td = 400 ms; Rp = 450
Operating Range Supply voltage Junction temperature Junction temperature Pre-induction
VS Tj Tj B0
4.5 - 40 - 40 0
24 150 170 200
V C C mT
thresholds may exceed the limits Southpole at the backside of IC
Semiconductor Group
6
TLE 4921-2
AC/DC Characteristics Parameter Supply voltage Junction temperature Supply current Symbol min. Limit Values typ. max. 4.5 V VS 24 V - 40 C Tj 150 C 3.5 4.0 Output saturation voltage VQSat Output leakage current Switching frequency Switching flux density 8.5 9 0.25 5 -2 0 14 14.5 0.6 10 mA mA V A Unit Test Condition Test Circuit
VS Tj IS
VQ = high IQ = 0 mA VQ = low IQ = 40 mA IQ = 40 mA VQ = 24 V C = 470 nF B = 5 mT f = 100 Hz; BO = 150 mT C = 470 nF;
B max = 1.75 mT
1 1 1 1 2 2
IQL f
BOP
20000 Hz 1 mT
Hysteresis
BHy
0.5
1.5
2.5
mT
f = 100 Hz; BO = 150 mT C = 470 nF;
B max = 1.75 mT
2
Overvoltage protection at supply voltage at output
VSZ VQZ
27 27
35 35
V V
IS = 16 mA IS = 16 mA
2 2
Semiconductor Group
7
TLE 4921-2
Figure 3 Test Circuit 1
- B0 = 100 mT; southpole at the back of IC - tooth wheel with module m = 2 mm - Distance IC-object L = 1 mm Figure 4 Test Circuit 2
Semiconductor Group
8
TLE 4921-2
Application Notes Two possible applications are shown in figure 7 and 8 (Toothed and Magnet Wheel). The differences 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 southpole of a permanent magnet (e.g. SECo5 (Vacuumschmelze VX145) with the dimensions 8 mm x 5 mm x 3 mm) which should cover both hall-probes. The maximum air gap depends on - - - - the magnetic field strength (magnet used), the tooth wheel that is used (dimensions, material, etc.), the ambient temperature, the connected capacitor
a centred distance of hall-probes b hall-probes to IC surface L IC surface to tooth wheel
a = 2.5 mm b = 0.25 mm
Figure 5 Sensor Spacing
Conversion DIN - ASA m = 25.4 mm/p t = 25.4 mm x CP DIN diameter (mm) number of teeth module m = d/z (mm) pitch t = x m (mm) ASA p diametral pitch p = z/d (inch) PD pitch diameter PD = z/p (inch) CP circular pitch CP = 1 inch x /p
d z m t
Figure 6 Tooth Wheel Dimensions
Semiconductor Group
9
TLE 4921-2
Figure 7 TLE 4921-2U, with Ferromagnetic Toothed Wheel
Semiconductor Group
10
TLE 4921-2
Figure 8 TLE 4921-2U, with Magnet Wheel
Semiconductor Group
11
TLE 4921-2
Figure 9 Application Circuits Semiconductor Group 12
TLE 4921-2
Figure 10 System Operation
Semiconductor Group
13
TLE 4921-2
Quiescent Current versus Supply Voltage
Quiescent Current versus Junction Temperature
Quiescent Current Difference versus Supply Voltage
Saturation Voltage versus Output Current
Semiconductor Group
14
TLE 4921-2
Maximum Preinduction versus Junction Temperature
Switching Induction versus Preinduction
Switching Induction versus Temperature
Hysteresis Induction Versus Junction Temperature
Semiconductor Group
15
TLE 4921-2
Distance IC-tooth Wheel versus Junction Temperature
Relative Distance versus Module
Relative Distance versus Switching Frequency
Fall- and Rise-Time versus Junction Temperature
Semiconductor Group
16
TLE 4921-2
Delay Time between Zero-Axis Crossing of B and Falling Edge of VQ at Tj = 25 C
Delay Time between Zero-Axis Crossing of B and Falling Edge of VQ at Tj = 160 C
Delay time Tj versus Junction Temperature for VS Switching from 0 V to 4.5 V
Influence of Filter and Delay Time for Different Bmax values
Semiconductor Group
17

▲Up To Search▲

Price & Availability of TLE4921

	To Download TLE4921 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .