ST ST7540, Application Note

Page: 18 / 55

Board description AN2451
18/55 Doc ID 12791 Rev 3
5.1 Coupling interface
The mains coupling interface is composed of three different filters: the Tx active filter, the Tx
passive filter and the Rx passive filter.
All three filters are described in the sections Section 5.1.1 , 5.1.2 , and 5.1.3 . In each section,
calculations and measured frequency responses are given.
The filters are quite sensitive to the components' value tolerance. Actual components used
in the ST7540 reference design have the following tolerances:
● +/- 10% for coils and for the X2 capacitor
●
+/- 1% for SMD resistors
● +/- 5% for SMD ceramic capacitors.
To evaluate sensitivity of the filters to the tolerances listed above, the following sections
include simulated responses of the filters with Montecarlo statistical analysis. Statistical
simulation helps understanding the relationship between components' value tolerance and
variations on the responses of the filters. In simulation curves, the ideal response is drawn in
blue, while red curves indicate statistical variations generated through simulation.
Table 4. ST parts on the ST7540 reference design board
Value Description
ST7540 Powerline transceiver
VIPER12AS SMPS controller / switch
STTH1L06A Ultrafast diode
STPS1H100 Schottky diode
SM6T12CA 12V bidirectional transil diode