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Is it OK to mix 4 wire SPI(ADF5902, ADF5904) with a 3 wire SPI interface of (ADF 4159).

Category: Hardware
Product Number: ADF 4159

In my custom board, We are planning to interface SPI 4 wire controller with 3 chip selects/latch enable for 3 different devices ADF5902, ADF 5904 and ADF 4159 ICs.

Here, PLL ADF4159 has SPI interface with a 3 wire (CLK, DATA_IN, LE) . However, VCO transmitter ADF5902 and Receiver ADF5904 have 4 wire SPI interface  (CLK, DATA_IN, LE, DATA_OUT) . Now due to lack of pins on output connector, I need to connect using common SPI controller with 3 devices with common Clk, DATA_IN, CE, DATA_OUT with 3 different LE (CS).
Now, Is it ok to mix 4 wire SPI (ADF5902 and ADF5904) with a 3 wire SPI interface of (ADF 4159)? Are there any other constraints I need to take care of ?
  • Hi PSA1, 

    You can mix 3-wire SPI with 4-wire SPI communication as long as each chip has an individual chip select line. 

    I recommend placing a 30Ohm series resistance on the SPI lines to prevent peaking at the edges of the clock line and data line.