TLE4998C3C Datasheet, PDF (34/42 Pages) Infineon Technologies AG – Programmable Linear Hall Sensor

TLE4998C3C
SPC Output Definition
calibrated, may be used for a plausibility check, for example. Table 21 shows the
mapping between junction temperature and the transmitted value in the SPC frame.
Table 21 Mapping of Temperature Value
Junction Temperature Typ. Decimal Value from Sensor Note
- 55°C
0
Theoretical lower limit¹⁾
0°C
55
25°C
80
200°C
255
Theoretical upper limit¹⁾
1) _{Theoretical range of temperature values, not operating temperature range}
The status nibble allows to check internal states and conditions of the sensor.
• Depending on the selected SPC mode, the first two bits of the status nibble contain
either the selected magnetic range or the ID of the sensor and allow therefore an easy
interpretation of the received data.
• The third bit is set to “1” for the first transmission after the sensor returns from an
overvoltage operation with disabled open drain stage to regular operation (see
Chapter 7.1).
• The fourth bit is switched to “1” for the first data package transferred after a reset. This
allows the detection of low-voltage situations or EMC problems of the sensor.
12.2
Unit Time Setup
The basic SPC protocol unit time granularity is defined as 3 µs. Every timing is a multiple
of this basic time unit. To achieve more flexibility, trimming of the unit time can be used
to:
• Allow a calibration trim within a timing error of less than 20% clock error (as given in
SAE standard)
• Allow a modification of the unit time for small speed adjustments
This enables a setup of different unit times, even if the internal RC oscillator varies by
±20%. Of course, timing values that are too low could clash with timing requirements of
the application and should therefore be avoided, but in principle it is possible to adjust
the timer unit for a more precise protocol timing. The output characteristic depends on
the external load, the wiring, as well on the pull-up voltage and the temperature.
Furthermore, sufficient driving capability of the sensor counterpart (ECU) is mandatory,
Data Sheet
34
Rev 1.1, 2009-09