Purpose of 2.2K resistors in the SPI bus of CYWUSB6934 | Cypress Semiconductor
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Purpose of 2.2K resistors in the SPI bus of CYWUSB6934
What is the reason for the 2.2K resistors in the SPI bus as shown in Figure 4-2 on page 4 of 27 of the CYWUSB6934 datasheet?
The reason for the 2.2K resistor shown in Figure 4-2 of the CYWUSB6932/34 data sheet is to limit the current. This has to be done because enCoRe devices are powered from the USB connector (VBus ~5.0volts source) while the WirelessUSB LS device is powered from 3.3volts source (LDO).
Hence, the radio chip needs some check over the current.