INFINEON TLE4942-2C

Data Sheet Supplement
Differential Two-Wire Hall Effect Sensor IC
TLE4942-2
TLE4942-2C
For all parameters not specified in this document the TLE4942 data sheet is valid.
P-SSO-2-1
Type
Marking
Ordering Code
Package
TLE4942-2
4202E4
Q62705-K633
PSSO2-1
TLE4942-2C
42C2E4
Q62705-K630
PSSO2-2
TLE4942-2, TLE4942-2C Supplement
1
Functional description
peak detection
initial
settling
time
d2
d2
offset= (m ax + min) / 2
offset correction
d1
d2
d1
0
standstill
pulse
(cut off)
1
2
3
4
5
6
7
PGA
switching
uncalibrated mode
calibrated mode
Fig. 1: example for start-up behaviour
Uncalibrated mode:
Occasionally a short initial offset settling time td,input might delay the detection of the
input signal. (The sensor is "blind").
The magnetic input signal is tracked by the speed ADC and monitored within the
digital circuit. For detection the signal transient needs to exceed a threshold (digital
noise constant d1). When the signal slope is identified as a rising edge (or falling
edge), a comparator is triggered. The comparator is triggered again as soon as a
falling edge (or rising edge respectively) is detected (and vice versa). Depending on
the initial state of the comparator the IC output is first triggerd on the first or second
detected edge.
Between the startup of the magnetic input signal and the time when its second
extreme is reached, the PGA (programmable gain amplifier) will switch to its
appropriate position. This value is determined by the signal amplitude and initial
offset value. The digital noise constant value is changing accordingly (d1 → d2),
leading to a change in phase shift between magnetic input signal and output signal.
After that consecutive output pulses should have a nominal delay of about 180°.
During the uncalibrated mode the offset value is calculated by the peak detection
algorithm as described in the TLE4942 data sheet.
Transition to calibrated mode:
In the calibrated mode the phase shift between input and output signal is no longer
determined by the ratio between digital noise constant and signal amplitude.
Therefore a sudden change in the phase shift may occur during the transition from
uncalibrated to calibrated mode.
TLE4942-2 - TLE4942-2C Data sheet supplement 2
February 2002
TLE4942-2, TLE4942-2C Supplement
Calibrated mode:
See TLE4942 data sheet.
Additional notes:
Unlike the TLE4942 the first output pulse might occur before the first zero-crossing of
the magnetic input signal. Therefore the maximum number of edges until the
calibrated mode is active is increased by one for TLE4942-2. However, referring to
the input signal the delay between startup of the signal and first calibrated output
signal is identical with TLE 4942.
Typically the phase error due to PGA-transition (row 7 to 15) reduces the error
caused by switching the mode from uncalibrated to calibrated.
In very rare cases a further PGA switching can occur during the calibration process.
It can take place when the signal is extremely close to a PGA switching threshold.
This additional switching might delay the transition to calibrated mode by two to three
more pulses. The probability of this case is mainly depending on variations of
magnetic amplitude under real automotive conditions. (See appendix B)
The direction detection feature is active in the calibrated mode only. Therefore
identical to TLE4942 the correct direction information is available after the first three
output pulses in calibrated mode. Regarding the rare case mentioned before
combined with other initial conditions this may lead to a worst case of 11 pulses
before correct direction information is guaranteed. The typical value is 5 pulses.
TLE4942-2 - TLE4942-2C Data sheet supplement 3
February 2002
TLE4942-2, TLE4942-2C Supplement
1
0
1
2
3
4
5
6
90...270°
150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal)
180° (cal)
180° (cal)
180°
(uncal)
180°
(uncal)
90...270°
150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal)
180° (cal)
180°
(uncal)
180°
(uncal)
180°
(uncal)
90...270°
150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal)
180°
(uncal)
180°
(uncal)
180°
(uncal)
180°
(uncal)
90...270°
45µs...737 180°...300°
ms
(PGA,
uncal)
45µs...737 180°...300°
8
ms
(PGA,
uncal)
45µs...737 180°...300°
9
ms
(PGA,
uncal)
45µs...737 180°...300°
10
ms
(PGA,
uncal)
45µs...737 180°...300°
11
ms
(PGA,
uncal)
180...220°
180°
180°
(uncal)
150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal)
12 45µs...737 45µs
ms
...180°
5
6
180°
(uncal)
10
180° (cal)
4
150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal)
9
180° (cal)
3
90...270°
8
180° (cal)
2
45µs...737 180°
ms
(uncal)
45µs...737 45µs
ms
...180°
(uncal)
45µs...737 45µs
ms
...180°
(uncal)
45µs...737 45µs
ms
...180°
(uncal)
45µs...737 45µs
ms
...180°
(uncal)
7
7
(uncal)
45µs...737 45µs
13
ms
...180°
(uncal)
45µs...737 45µs
14
ms
...180°
(uncal)
45µs...737
45µs
15
ms
...180°
(uncal)
(uncal)
150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal)
180° (cal)
180° (cal)
180° (cal)
180°
(uncal)
180...220°
150°..200° 150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal) (cal/uncal)
180°
(uncal)
180°
(uncal)
90...270°
150°..200° 150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal) (cal/uncal)
180°
(uncal)
180°
(uncal)
180°
(uncal)
90...270°
150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal)
180°
(uncal)
180°
(uncal)
180°
(uncal)
180°
(uncal)
90...270°
180°...260° 180...220°
180°
(PGA,
uncal)
(uncal)
150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal)
180°...260° 180°
(PGA,
(uncal)
uncal)
150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal)
180° (cal)
180° (cal)
180...220°
150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal)
180° (cal)
180°...260° 180°
(PGA,
(uncal)
uncal)
180°
(uncal)
90...270°
150°..200° 150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal) (cal/uncal)
180°...260° 180°
(PGA,
(uncal)
uncal)
180°
(uncal)
180°
(uncal)
90...270°
150°..200° 150°..200° 180° (cal)
(cal/uncal) (cal/uncal)
Table1: overview of the startup-behaviour.
In the first row the pulse number is given. Pulse number 0 is the last pulse before signal
startup, e.g. the standstill (stopped) pulse. The following rows show different possibilities for
the nominal delays between the pulses. Numbers are calculated for sinusoidal input signals.
Additionally the specified tolerances have to be taken into account (e.g. Jitter)
Rows 2..6: behaviour at small input amplitudes (∆B< approx. 3.5mT)
Rows 7..11: behaviour at initial phases of –90° .. 0°
Rows 12..15: behaviour at initial phases of 0°.. 90°
Remark: the additional PGA switching can only occur once per row. Therefore also the
additional phase shift marked "150°..200° (cal/uncal)" will only occur once per row. (see
example)
TLE4942-2 - TLE4942-2C Data sheet supplement 4
February 2002
TLE4942-2, TLE4942-2C Supplement
Example: The 14th row describes the behaviour shown in Fig. 1: The standstill pulse length
can be cut by the first detected speed pulse, therefore the minimum distance between the
rising edges will be 45µs. The distance between the first and second detected speed pulse is
determined by the initial signal phase and amplitude and a possible first PGA switching. As
the first pulse length also can theoretically be cut off by the following pulse, the minimum
distance could be 45µs. The rising edge between the first signal minimum and the first signal
maximum can cause the PGA switching into a lower gain range. As a result the digital noise
constant value can increase in relation to the signal amplitude. That typically leads to an
increased delay between the second and the third pulse, its maximum value is 260°. The
following minimum and maximum are necessary for peak detection. After offset correction,
the delay between the 5th and the 6th pulse can have a maximum value 270°. As this marks
the transition from uncalibrated to calibrated mode, the following consecutive pulses (4, 5, 6
...) will be spaced 180° nominally.
Same example with numbers: ∆B = 10mT sin (ωt + ϕ). ϕ = 30°
Typical startup-behaviour at a sinusoidal input signal of 10mT amplitude, initial phase= 30°.
1
2
ϕ 43,6° 133,9°
∆ϕ
90,3°
(PGA,
uncal)
3
4
5
6
7
8
9
10
333,2°
513,2°
693,2°
900°
1080°
1260°
1440°
...
199,3°
(PGA,
uncal)
180°
(uncal)
180°
(uncal)
206,8°
(Offsetcorrection)
180°
(cal)
180°
(cal)
180°
(cal)
180°
(cal)
→ This corresponds to row 14 in the table, behaviour similar to Fig. 1
As a special (and rare) case instead of an offset correction after edge number 5, a further
(extra) PGA switching could occur before edge number 5. PGA switching inhibits an
immediate offset update. It can happen if one of the signal peaks is exactly at a PGA
switching threshold (speed-ADC overflow). In this case the offset update (switching from
uncalibrated mode to calibrated mode) would be delayed by two to three further edges. The
referring phase shifts of the example would then be as follows:
1
2
ϕ 43,6° 133,9°
∆ϕ
90,3°
(PGA,
uncal)
3
4
5
6
7
8
9
10
333,2°
513,2°
727,5°
907,5°
1087,5°
1260°
1440°
...
199,3°
(PGA,
uncal)
180°
(uncal)
214,3°
(extra PGA)
180°
(uncal)
180°
(uncal)
172,5°
(Offsetcorrection)
180°
(cal)
180°
(cal)
→ This corresponds to row 13 of the table.
TLE4942-2 - TLE4942-2C Data sheet supplement 5
February 2002
TLE4942-2, TLE4942-2C Supplement
Circuit Description
See TLE4942 data sheet
TLE4942-2 - TLE4942-2C Data sheet supplement 6
February 2002
TLE4942-2, TLE4942-2C Supplement
2
Additions/Changes for TLE4942–2 versus TLE4942
(All values are valid for constant amplitude and offset of input signal, f<2500Hz)
Parameter
Signal behaviour after
undervoltage or
standstill>tStop
Symbol
min.
typ.
max. Unit
nDZ-Start
Conditions
Magnetic edge
amplitude according to
∆Bˆ
Limit, early startup
Edges that occur before
nDZ-Start can be
suppressed
Systematic phase error
of output pulses during
startup- and
uncalibrated mode
Phase shift change
during PGA switching
Phase shift change
during transition from
uncalibrated to
calibrated mode
Number of pulses in
uncalibrated mode
in rare cases (see
appendix B)
Number of pulses with
invalid supplementary
information
in rare cases (see
application notes)
∆Φswitch
2
pulses
3
pulses
38
45
52
µs
38
45
52
µs
-88
+88
°
0
80
°
-90
+90
°
nDZ-Startup
6
pulses
nDZ-Startup
8
pulses
nDR-Startup
9
pulses
11
pulses
1Hz ≤ f ≤ 2000Hz
f > 2000Hz
td,input has to be taken
into account
Shortest time delay
between pulse 0 (stop
pulse) and pulse 1
td,input has to be taken
into account
Shortest time delay
between
wheel speed pulse 1
and 2
Systematical phase
error of “uncal” pulse;
nth vs. n+1th pulse
(does not include jitter)
After nDR-Startup pulses
the supplementary
information is correct
(starting with the
nDR-Startup+1-th pulse the
pulse length is correct)
nDR-Startup
TLE4942-2 - TLE4942-2C Data sheet supplement 7
February 2002
TLE4942-2, TLE4942-2C Supplement
Parameter
Symbol
Jitter during startup
and uncalibrated
mode
min.
typ.
max.
Unit
Conditions
SJitClose
±3
%
-40°C ≤Tamb ≤ 150°C:
(1σ-value)
±4
%
150°C ≤Tamb ≤ 170°C:
SJitFar
±5
%
-40°C ≤Tamb ≤ 150°C
(1σ-value)
±7
%
150°C≤Tamb ≤170°C
SJitAC
±3
%
see TLE 4942 spec
(1σ-value)
Magnetic field
amplitude change
necessary for early
startup of the –2
Versions
∆Bˆ
∆Bˆ Limit, early
Limit, early startup
0.7
> 2 * ? Bˆ Limit + X% (X
= 10)
Permitted time for
edges to exceed
∆BˆLimit,
These magnetic field
changes are necessary
for startup with the
second magnetic edge
startup
0.7
1.6
3.0
+10% +10%
1.76
∆t Limit, slow
early startup
3.3
590
mT
mT
ms
necessary for startup
with the second edge
f < 1s
early startup
Behaviour at magnetic input signals slower than Tstop (self-calibration time period):
Unlike the TLE4941 magnetic changes exceeding ∆BˆLimit, early startup can cause output switching
of the TLE4941-2, even at f significantly lower than 1Hz. Depending on their amplitude edges
slower than ∆t Limit, slow early startup might be detected. If the digital noise constant ( ∆BˆLimit,early startup )
is not exceeded before a new initial self-calibration is started, the output of the corresponding
edge will be inhibited. This depends on signal amplitude and initial phase.
3
Additional remarks
All additional parameters for TLE4942-2 are guaranteed by design, based on lab
characterisations. For series production additional to the parameters of TLE4942
(standard type) only nDZ-start is tested.
TLE4942-2 - TLE4942-2C Data sheet supplement 8
February 2002
TLE4942-2, TLE4942-2C Supplement
Appendix B: TLE4942-2 Application Notes Release 1.0
1. Occurrence of initial calibration delay time td,input
Identical to TLE 4942, TLE 4942 C Application notes.
2. 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 occurs within
less than one signal period. This is included in the calculation for nDZ-Startup. For the very rare
case that the signal amplitude is extremely close to a switching threshold of the PGA and the
the full range of 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 pole-wheel, tooth wheel or air gap variation). This
additional PGA switching can result in a further delay of the output signal (nDZ-Startup) up to
three magnetic edges leading to a worst case of nDZ-Start=9 and nDR-Startup=11.
However, the speed signal startup, comprised of nDR-Startup and td,input is not affected by this
behaviour for TLE 4942-2.
3. - 6. Identical to TLE4942, TLE4942C Application notes.
TLE4942-2 - TLE4942-2C Data sheet supplement 9
February 2002