tle4942 Infineon Technologies Corporation, tle4942 Datasheet - Page 28

• Manufacturer Part Number: tle4942
• Description: Differential Two-wire Hall Effect Sensor-ic For Wheel Speed Applications With Direction Detection
• Manufacturer: Infineon Technologies Corporation

TLE4942-1
TLE4942-1C
Appendix B
Release 2.0
t
Occurrence of initial calibration delay time
d, input
If there is no input signal (standstill), a new initial calibration is triggered each 0.7 s. This
t
calibration has a duration
of max. 300 µs. No input signal change is detected
d, input
during that initial calibration time.
t
In normal operation (signal startup) the probability of
to come into effect is:
d, input
t
/time frame for new calibration = 300 µs/700 ms = 0.05%.
d, input
t
After IC resets (e.g. after a significant undervoltage)
will always come into effect.
d, input
Magnetic input signal extremely close to a PGA switching threshold during signal
startup
After signal startup normally all PGA switching into the appropriate gain state happens
n
within less than one signal period. This is included in the calculation for
. For the
DZ-Startup
very rare case that the signal amplitude is extremely close to a PGA switching threshold
and the full range of the following speed ADC respectively, a slight change of the signal
amplitude can cause one further PGA switching. It can be caused by non-perfect
magnetic signal (amplitude modulation due to tolerances of polewheel, tooth wheel or air
gap variation). This additional PGA switching can result in a further delay of the
calibrated output signal up to two magnetic edges leading to a worst case edges of
n
= 8.
DZ-Start up rare
For a more detailed explanation please refer to the document
"TLE4941/42 Application Notes - Frequently Asked Questions".
Data Sheet
28
V3.1, 2005-03