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LMX8410L: CE pin

Noriyuki Takahashi
Genius 10420 points
Part Number: LMX8410L

Hi team

 

Customer has questions about the CE (pin1) port function of the LMX8410L. Could you support?

Q1. If CE port is enabled, will the register information set by SPI be retained?

Q2. If CE port is enabled, will all RF functions (PLL, LO AMP, MIXER) lose their functions? Will the power consumption at that time be greatly reduced?

Q3. If you change the CE port from disabled to enabled, please tell me the time it takes to restore the RF function.

Regards,

Noriyuki Takahashi

  • +1
    TI__Mastermind 31750 points

    Hi Takahashi-san,

    CE pin is a powerdown pin, toggling CE powers down internal LDOs for everything except digital.

    1. Toggling CE LOW does not clear register contents. Register contents will be retained next time CE goes HIGH.
    2. Toggling CE LOW disables all elements in the device except the digital. PLL, LO AMP, and MIXER will all be disabled. Power consumption will be greatly reduced, I measure about 10mA with CE LOW.
    3. This time is variable and depends on the size of the VCO bias capacitors. If you are using the internal VCO it will be several hundred microseconds, and we typically recommend waiting 1ms before assuming function is restored (we can reduce this time slightly by shrinking the capacitors on VBIAS_VCO1, VBIAS_VCO2, and VBIAS_VARAC, but this reduces internal VCO phase noise performance). If you are using external LO and the PLL is not used, restart time will likely be much quicker, but we have never measured it.

    Regards,

    Derek Payne