E981.07 Datasheet, PDF (43/46 Pages) ELMOS Semiconductor AG – Two independent operating channels

Two Channel Sensor Interface PSI5
ADVANCE PRODUCT INFORMATION JUL 26, 2011
6 Application notes
E981.07
6.1 Recommended application circuits
To ensure proper operation of the interfaces with the wiring harness and the sensors the following
recommendations have to be taken into account.
The regulator in the interface does not need a stabilisation capacitance to prevent instability. Nevertheless
external components are needed to reduce ringing at the output, especially in case of large inductors connected
to the pin.
98107
SATFDx
AGND
RE
CE
Figure 6.1-1: Recommended ECU-board circuitry
RE should be between 3.3Ohms and 12Ohms (5Ohms are the minimum resistance conform to PSI-5
specification). The resistor reduces the oscillations coming from the wiring harness. It damps the influence of
the wiring inductor and leads to an, over the frequency range constant, termination resistor.
The capacitor CE ensures a minimum input capacitance and is also mandatory to achieve a sufficient ESD-
performance. The next figure shows further possible ECU-circuits. The capacitor CEopt removes potential
oscillations in short circuit conditions. If RE is chosen to be less than 3.3Ohms CEopt should be larger 4.7nF,
with 10nF no oscillation in short circuit conditions have been observed
RE
RE
CE
CEopt
CE
Figure 6.1-2: further recommended ECU-board circuits
ELMOS Semiconductor AG
Data Sheet 43 / 45
QM-No.: 25DS0050E.00
This document contains information on a new product. ELMOS Semiconductor AG reserves the right to change specifications and information herein without notice.