TLE4998P8D Grade1

General

Technical Product Description

10

Revision 1.0, 2014-05-21

2.3

Principle of Operation

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A magnetic flux is measured by a Hall-effect cell

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The output signal from the Hall-effect cell is converted from analog to digital signals

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The chopped Hall-effect cell and continuous-time A/D conversion ensure a very low and stable magnetic offset

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A programmable low-pass filter to reduce noise

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The temperature is measured and A/D converted

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Temperature compensation is done digitally using a second-order function

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Digital processing of the output value is based on zero field and sensitivity value

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The output value range can be clamped by digital limiters

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The final output value is transferred in a rectangular, periodic signal with varying duty cycle (Pulse Width

Modulation)

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The duty cycle is proportional to the 12-bit output value

2.4

Further Notes

Product qualification is based on “AEC Q100 Rev. G” (Automotive Electronics Council - Stress test qualification

for integrated circuits).

2.5

Transfer Functions

The examples in Figure 2-2 show how different magnetic field ranges can be mapped to the desired output value

ranges.

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Polarity Mode:

– Bipolar: Magnetic fields can be measured in both orientations. The limit points do not necessarily have to

be symmetrical around the zero field point

– Unipolar: Only north- or south-oriented magnetic fields are measured

•

Inversion: Both gain can be set to positive values, negative values or positive/negative values.

Figure 2-2

Examples of Operation

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-50

100

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0

B (mT)

B (mT)

B (mT)

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Example 1:

-Bipolar

Example 2:

-Unipolar

-Big offset

Example 3:

- Bipolar

- Inverted (neg. gain)