Need replacement for discontinued BBA chip!

Discussion in 'The Projects Forum' started by cds333, Aug 1, 2014.

  1. cds333

    Thread Starter Member

    Nov 5, 2007
    Linx BBA 519/322

    So these things are incredibly useful but for some reason they are no longer being made.

    I am wanting a replacement for these two, but mainly the 519. Something that I can drop in between a transmitter and the antenna, such as is depicted in the "typical applications" section of the above sheet.

    When I search for general purpose RF amp on digikey there are over 800 results. My electronics proficiency is intermediate, so I really don't know the difference between all the different types of RF amplifier chips.

    And no the company did not have any suggestions :(

    Many thanks in advance!
  2. timwhite


    Apr 10, 2014
    The ADL5544 seems to match up pretty well with the BBA 519, it's a little pricey though at 4 bucks a pop.

    Here's a link: Digikey - ADL5544ARKZ-R7

    Should work for whatever you were using it for! Maybe a little bit different wiring. Relatively similar gain and current though.
  3. Papabravo


    Feb 24, 2006
    So these things are BROADBAND amplifiers. Tell me why you need a broadband amplifier. Are you using signals over such a wide bandwidth? The reason I ask is that you might have more success with a redesign if you state your requirements.

    The ADL5544 has a lower frequency range of 30 MHz and an upper range of 6 GHz. It looks like a SOT-89 package.

    Your original part was 10 MHz to 3 GHz. in and 8-pin SMD package, so the AD part is not exactly a "drop-in" replacement. So please clarify your requirements so we have at least a snowballs's chance in Florida of helping you.
    Last edited: Aug 1, 2014
  4. Lestraveled

    Well-Known Member

    May 19, 2014
    1,224 would be the first place I would look for that kind of amp.
  5. Papabravo


    Feb 24, 2006
    Great, except we don't really know what kind of amp he needs, and he said his skills for identifying a replacement part are intermediate, so we really really need to know what the actual requirements are, preferably all at once as opposed to dribble-drab.
  6. cds333

    Thread Starter Member

    Nov 5, 2007
    Of course, I should have been more clear. I am using them in conjunction with the Linx transceiver and transmitter chips produced by the same company. Actually the aforementioned datasheet displayed pretty much exactly what I'm using it for.

    The ES Series Transmitter would be one use, which is an 800/900 MHz FM/FSK transmitter.

    The BBA 519 was supposed to work well with the other transmitters such as the LR Series which is a 260-470 MHz serial OOK transmitter chip.

    The original part just dropped in between the transmitter output and the antenna and boosted the power output.

    So anything that boosts output power for those types of single-chip transmitters, preferably without additional tuning circuitry, if that is possible; and form factor or package type doesn't matter, actually DIP would be easiest for me to solder but if it's SMT only that's fine too.

    And then there was the BBA 322 which did the same thing only for the receivers. But if you can only find one replacement for me I would choose the 519 first.

    Tim- Thanks so much for your suggestion! Honestly I don't know what exactly a gain block amp is, even after looking at the datasheet and googling it I'm still not sure; there's not a lot of info about them. That would be for increased output power correct? The 519 is listed as an "RF AMP HI-POWER BROADBAND" and the 322 as "RF AMP HI-GAIN BROADBAND". I'm not too clear on how the two differ internally, but I had thought the high-gain one was for boosting the signal to the receiver. Unfortunately the datasheet on the ADL5544 does not list common uses.

    I would find it hard to believe that there was only one company making these in the whole industry, and there was so little demand for them they just stopped. I hadn't got the chance to formally test their capability but if they do half of what they claim they would be incredibly useful.

    Thanks much!
    Last edited: Aug 4, 2014
  7. Papabravo


    Feb 24, 2006
    It is probably the case that the discontinued parts are made in an obsolete fab. All chips have a finite production run and when the line stops, there is either a replacement part with a smaller geometry or there isn't. Once a part goes EOL there is very little motivation to restart an obsolete fab.

    My suggestion is to look for a family of narrow band amplifiers. You will get much better receiver performance with respect to incidental noise sources. You could get a bandpass amplifier for 800/900 and another one for 250/500.

    As to the difference between receivers and transmitters. You can have two blocks with an identical gain of +30 dB. One of them has a power output of say -60 dBm which would be suitable for a receiver, and the other has a power output of say +30 dBm which would be suitable for a transmitter. See the difference?
    Last edited: Aug 4, 2014
  8. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Useful for what? Violating the allowed emission limits? I suspect that these are no longer available because the FCC and/or EU equiv shut them down...
  9. cds333

    Thread Starter Member

    Nov 5, 2007
    No they didn't mention anything about that. And if you check the datasheet you will notice that they do not have a fixed output power; the output is dependent on the input; if you had designed a transmitter that is meant for short range and operates at 10% of max legal output, and for some reason you wanted to retrofit your product line to increase range you can drop this in with no additional circuitry. And the other one is meant to increase the sensitivity of a receiver. It just so happens that they can also be used to boost output power of their line of transmitters if you live in an area without restrictions.

    Bravo, thank you for your suggestion. I will check out some digikey results within a narrow band search and likely ask for a recommendation when I find some I think may be suitable.

    And the reason I was confused as to which was for the reciever and which was for the transmitter is because they both have similar listed specs:

    The 322, which is meant for recievers, lists:
    +20dB small signal gain at 900MHz
    Up to +10dB (10mW) linear output power

    And the 519, which is for transmitters, lists:
    +18dB small signal gain at 900MHz
    Up to +17dB (50mW) linear output power

    I'm sure I'm missing something that an EE would probably point out, but to me they look like they might be almost interchangeable.

    Thanks again!
    Last edited: Aug 7, 2014
  10. bertus


    Apr 5, 2008

    Have a look at the MMIC's in th following PDF:
    ERA and MAR MMIC's

    The ERA 5 will do what you want.