sx8724s Semtech Corporation, sx8724s Datasheet - Page 43

• Manufacturer Part Number: sx8724s
• Description: Zoomingadc For Sensing Data Acquisition
• Manufacturer: Semtech Corporation

Revision 1.0
© Semtech
9.5 Improving Noise Immunity
Noise may cause incorrect device operation and incorrect data reception. Careful circuit design and PCB layout
prevents much of the problems. Noise immunity can be improved using the following methods:
The SCLK, MISO, MOSI and SS lines can also be decoupled with capacitors to increase noise performance. The values of
R and C then depend on the transmission speed of the SPI bus. For a transmission speed of around 100 kHz, an R of 100
Ω and C of 1nF is suggested. For higher transmission speeds, the values of R and C should be reduced accordingly. But
if the operating environment is very noisy, larger values of R and C must be selected, and the transmission speed
should be reduced.
ADVANCED COMMUNICATIONS & SENSING
The recommended value for theses resistors is around 100 Ω.
Keep SPI lines on the PCB away from noisy lines and devices such as switchers.
Terminate SPI lines at the device using termination resistors as shown in
February 2011
Figure 31. Resistors to improve noise immunity between master and slave
MASTER
MISO/READY
SCLK
MOSI
SS
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100
100
10K
100
ZoomingADC for sensing data acquisition
SCLK
MOSI
MISO/READY
SS
Figure
31.
SX872xS
SLAVE
SX8724S
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