UM1557 Datasheet, PDF (100/111 Pages) STMicroelectronics – The aim of this document is to give the design engineer

Operation with AMICO
Figure 70. Distortion of the SPI signal by a too high series resistor

UM1557
8.8.2

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Table 15.
Recommended max. SPI clock frequency as a function of the series
resistance
Resistor value
Max. recommended SPI clock frequency
1k
2.2 k
4.7 k
10 k
1 MHz
1 MHz
500 kHz
250 kHz
A 1 kΩ series resistor on these pins is generally a good compromise between the data rate
and decoupling between µC/AMICO.
Interface HSD/AMICO
This section deals with external components between the HSD and AMICO, in order to
protect the devices against ISO transients and reverse battery conditions. A differentiation
between monolithic (VND5T035Ax, VND5T050Ax, VND5T100Ax) and hybrid devices is
done (VN5T006ASP, VND5T016ASP, VN5T016AH).
ISO pulses on monolithic devices
Negative ISO pulses are directly transferred to the HSD’s input pin (noted IN) and the
FR_Stby and CS pins of monolithic devices. The worst case is when no load is connected to
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