LMX2571: Settings for 196.05 MHz (warning for VCO)

Alex Strelbytskyy

Expert 1960 points

Part Number: LMX2571
Other Parts Discussed in Thread: USB2ANY,

Hello,

I'm working with LMX2571EVM board connected to PC using USB2ANY module. I have st up the port TX (Set of settings F1) to the test frequency 440MHz and it works fine.

I have problems to set up frequency 196.050 MHz on the port RX (Set of settings F2). Some edit boxes e.g. VCO have red background, what does it mean? The VCO=1568.4 MHz that is in the proper range 4.3-5376MHz. I don't see expected tone on the port RX. How could it be fixed? Could you provide settings for Fref = 40 MHz, FoutTX=440MHz and FoutRx=196.05MHz?

Thanks,

Alex

over 6 years ago

0 Derek Payne over 6 years ago

TI__Mastermind 33950 points

Hello Alex,

Unless you are using an external VCO, 1568.4 MHz is out of range for the LMX2571 internal VCO. The range is 4300 MHz to 5376 MHz.

To push the VCO frequency back into the usable range, I find that VCO = 4705.2 MHz, with a channel divide of 24 (SEG1 = 6, SEG2 = 4), should generate FoutRx = 196.05 MHz.

Regards,

0 Alex Strelbytskyy over 6 years ago in reply to Derek Payne

Expert 1960 points

Thanks.

Clock & timing

Clock & timing forum

LMX2571: Settings for 196.05 MHz (warning for VCO)