Impedance Matching

Why Add 22Ω or 33Ω Resistors to SPI Signal Outputs?

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Why Add 22Ω or 33Ω Resistors to SPI Signal Outputs?

Click the blue text above to follow us The main reason for adding a 22Ω or 33Ω resistor in series when a microcontroller uses SPI to connect to a sensor or controller is to suppress reflections and ringing. 1 Principle of Reflection and Source Matching In high-speed digital signal transmission, when the signal driver (such … Read more

Why Add 22 or 33 Ohm Resistors to SPI Signal Outputs?

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Why Add 22 or 33 Ohm Resistors to SPI Signal Outputs?

For more experience sharing, follow RF Engineer When a microcontroller or FPGA sends SPI control signals to a phase-locked loop chip, it often requires a series connection of a 22 ohm or 33 ohm resistor. What is the reason for this? Impedance discontinuities can cause electromagnetic wave reflections, which in turn lead to signal distortion. … Read more