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Vtune out-of-spec of HMC733

Category: Hardware
Product Number: HMC733

Hi, all. We're developing a frequency synthesizer using HMC733 and ADF41513.

HMC733 datasheet promise around Vtune of 18V for output of 20 GHz. But we observed 21.2 V for output of 20 GHz.

(we measure Vtune and output freq. as dot in the illustration above)

Does out-of-spec Vtune affect output power? The output power is -8.2 dBm after power splitter(EP2k-19+) and dc-block cap.

We would also like to check if this is caused by device aging. The lot number is HV64.

  • Hi,

    The plots given in the datasheet are typical performance characteristics and thus they are not guaranteed or promised specs. Vtune for a given frequency will vary substantially over process/temperature and other circuit characteristics. So it is not reasonable to be able to spec a particular vtune at a particular frequency. The plot is to serve as an guideline only.

    The spec table min/max values given on page 1 are the performance we guarantee, since these would be tested limits. For vtune you can see the spec is -0.25 to 23V. So the performance you have measured is not out of spec.

    Regards,

    Alex

  • We have also seen this high tune voltage. Normally, higher Vt is not an issue, but with these devices, the higher Vt  parts, the Vt will change or drift over time. Typically with Vt >20V@20GHz, the part will continue to drift higher over time/ /temp. We replace any parts that require >20V to tune to 20GHz (or is seen to drift) as we have seen most of these will continue to drift up in voltage exceeding our circuit limits. So far only about 5% of the parts have experiences the higher Vt voltages and drift. We have seen 23V @20GHz.  We have not seen this drift from parts that are typically Vt=18V. Also, the drift does not seem to ever stabilize or stop.

    You may want to let the circuit run over nite and see if the Vt  is drifting.

  • Hi,

    Would you be able to provide date codes for parts that you see this occur, and also date codes for parts that this doesn't occur?

    It would be good to narrow down the issue. 

    Regards,

    Kieran 

  • Hi,

    I've looked into this issue and confirmed that there was an assembly issue with some lots of HMC733. It has since been resolved. You will need to initiate a replacement return for these parts.

    Regards,

    Kieran