TLE4998S3C Datasheet, PDF (32/36 Pages) Infineon Technologies AG – Programmable Linear Hall Sensor

TLE4998S3C
SENT Output Definition (SAE J2716)
It is important to know that the sampling time (when values are taken for temperature
compensation) here is always defined as the beginning of the synchronization period;
during this period, the resulting data is always calculated from scratch.
As only one Hall value needs to be transferred within one sequence, the second data
package is divided into two parts (see Table 19):
• First, the remaining 4 LSBs of the Hall signals are transferred in the first data nibble.
This means the receiver may use the whole 16-bit data available in the sensor when
reading and using all 4 nibbles transferred.
• Second, the temperature is transferred as an 8-bit value. The value is transferred in
unsigned integer format and corresponds to -55°C to 200°C. For example, transferring
the value 55 corresponds to 0°C. The temperature is additional information and
although it is not calibrated, may be used for a plausibility check, for example.
Table 17 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.
• The first two bits of the status nibble contain the selected magnetic range of the sensor
and therefore allow the received data to be interpreted easily.
• 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 SENT 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
Data Sheet
32
Rev 1.1, 2009-09