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HMC349A and HMC472A

hi, what is the difference between HMC349 with HMC349A, and HMC472 with HMC472A? thanks.


Some HMC products are/will be obsolete due to foundry/process discontinuation. Many of these have/will have replacement products designed in a similar process from a different foundry targeting functional drop-in replacement. "A" suffix on the part number is used to identify replacement products.

The HMC349A/HMC472A are the FFF (form, fit, functional) replacements of the HMC349/HMC472 and existing applications of original parts can switch to replacement parts without any change in design/performance.


  • thanks, Selcuk.

    Are there any change about the internal structure, such as voltage control pins(V1 to V6) of HMC472A?

    customer used HMC472 in his previous design, and in quiescent testing, the earth impedance is about 50Kohm, but for HMC472A, it is 1Mohm. could you please help check about this?

  • Hello,

    HMC472ALP4E is completely a new design in a GaAs process from another foundry by targeting to meet or exceed the electrical performance/operating conditions of old HMC472LP4E.

    Due to redesign of integrated 1-to-2 logic driver circuitry on each control paths (V1-V6), there could be some change in control current but the change is not such significant as you measured.

    HMC472LP4E and HMC472ALP4E is measured to have control input resistances of around 150k and 100k respectively.


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