TLE4998C3C Datasheet, PDF (35/42 Pages) Infineon Technologies AG – Programmable Linear Hall Sensor

TLE4998C3C
SPC Output Definition
in order to be able to maintain the herein given master pulse requirements. All these
parameters have considerable influence to find the proper unit time setup.
Table 22 Predivider Setting
Parameter
Symbol Limit Values
min. max.
Register size
Prediv
4
Unit time
t_UNIT
2.0 3.88
1) _{Prediv default is decimal = 8 for 3 µs nominal SPC unit time}
2) _{RC oscillator frequency variation +/- 20%}
Unit
bit
µs
Notes
Predivider¹⁾
Clk_UNIT=8MHz²⁾
The nominal unit time is calculated by:
t_UNIT = (Prediv + 16) / Clk_UNIT
Clk_UNIT = 8MHz ± 20%
12.3
Master Pulse Requirements
An SPC transmission is initiated by a Master pulse on the OUT pin. To detect a low level
on the OUT pin, the voltage must be below a threshold V_thf. The sensor detects that the
OUT line has been released as soon as V_thr is crossed. Figure 12 shows the timing
definitions for the master pulse. The master low time t_mlow as well as the total trigger time
t_mtr are individual for the different SPC modes and are given in the subsequent sections.
It is recommended to chose the typical master low time exactly between the minimum
and the maximum possible time: t_mlow,typ = (t_mlow,min + t_mlow,max) / 2. Although the
allowed timing windows are larger for longer low times, the master should use a quarz
clock source to provide a high timing accuracy (approx. 1%). For improved robustness,
the master pulse can be adopted by the master once the effective unit time is known
through the sensor’s synchronisation period length. If the master low time exceeds the
maximum low time, the sensor does not respond and is available for a next triggering
Data Sheet
35
Rev 1.1, 2009-09