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LMX2820: OUTB_PD specification

Part Number: LMX2820


Tool/software:

Hi,

In the datasheet for LMX2820 there is a specification for the dynamic range and speed of the MUTE function (using the external pin), i.e. Pmute, tMute, tUnmute.

Similar to the mute function I'm interested in switching between the A and B outputs, i.e. either the A or the B output is muted and the other enabled. I would only switch between A and B output at the same time as performing an instant calibration, so this switching doesn't have to faster than the VCO calibration. I will use DBLBUF_OUTBUF_EN to make sure the switch happens at the calibration instant.

Questions:

  • How fast is the enable/disable when changing the state of OUTA_PD/OUTB_PD, i.e. turn-on and turn-off settling times (given some definition of settling error)?
  • What's the leakage output power level for a powered down output?

I'm basically contemplating if I can use this functionality to substitue an external SPDT switch.

Thanks!

  • Hi Christer,

    Power down time is very short, in nano-second range. 

    Power up takes longer time, approx. 1.5µs. You can ignore the DC-level change in below plot, this is due to the AC-coupling capacitor (0.1µF). 

    Power down power with power setting = 7.

    -56dBc at 5.5GHz

    -72dBc at 11GHz

    -59dBc at 22GHz