Information about the application circuit of the TLE 4917
Vs
Sensor
R =2700
L
W
1 Vs
6 Prg
Output
S1
TLE 4917
C= 10 nF
2 Gnd 5 Gnd
3 Q
4 Gnd
Gnd
Application circuit TLE 4917
The minimum value for the pull up resistor can be calculated with the power supply voltage
Vs, the maximum current IQmax and the minimum output saturation voltage VQSAT
.
Example:
for Vs = 3 V: RLmin = (Vs - VQSATmin)/IQmax = (3 V - 0,1 V)/0,002 A = 1435 W
Larger values for RL will reduce the current IQ and therefore the power consumption. If the
resistor RL is very large (>100 kW) a capacitor (app. 10pF) between Output and GND pin
could be useful if capacitive coupled noise occurs.
The load at the output Q should have a large input resistance to reduce the current trough
RL and the power consumption.
The TLE 4917 has 3 ground pins. From a mechanical point of view all ground pins should
be connected to ground. Shortest wires should be used to avoid ground loops.
If there is a need to reduce the number of used ground-pins any ground-pin combination
may me used. Furthermore it is possible using only one ground-pin at the application, all
pins are equivalent.
The capacitor C is highly recommended to reduce noise on the power supply voltage and it
will improve the EMI/EMC performance.
Furthermore it decreases the transient peak supply current during operation time. The IC
toggles between low and high current consumption. This behaviour might produce
additional noise at the power supply. The capacitor will reduce this noise.
Furthermore this capacitor is used to supply the sensor if microbreaks (short loss of supply
voltage) occur.
Shortest connection wires between IC and capacitor should be used to avoid noise.
The switch S1 shows the programming feature of the output.
Example:
If the PRG-pin is connected to Vs the IC will hold the output Q at a high voltage level for B= 0 mT in this circuit. A
magnetic field larger than the operating point will switch the output to low level. In typical applications the PRG-pin is
connected directly to Vs or to GND depending on the technical needs. Avoid using a floating PRG-pin.
Data Sheet
12
INFINEON [ Infineon ]
