Replacement: None. We are no longer carrying this part. This page is for reference only.

The SMA661AS is the first low-noise amplifier with integrated matching networks and embedded power-down function in an incredibly tiny SOT666 package. The chip, which requires only one external input capacitor, drastically reduces the application bill of materials and the PCB area, resulting in an ideal solution for compact and cost-effective GPS LNA.

The SMA661AS, using the ST’s leading-edge 70GHz SiGe BiCMOS technology, achieves excellent RF performance at the GPS frequency of 1.575GHz, in terms of power gain, noise Figure and linearity with a current consumption of 8.5mA. The device is unconditionally stable and ESD protected.

  • SOT666 package
  • Power down function
  • Integrated matching networks
  • Low noise figure 1.15dB @ 1.575 GHz
  • High Gain 18dB @ 1.575 GHZ
  • High linearity (IIP3 = +3bBm)
  • Temperature compensated
  • ESD protection (HBM +/- 2kV)
  • 70GHz SiGe Technology
  • Operating temp -40C to +85C

Customer Comments

  • Maybe SFE will stock ST’s eval board for this. I doubt a standard breakout would work well, if at all, due to line length constraints in RF circuits. The chip is small for a reason: to save PCB space in a tightly integrated RF layout. Making a breakout board on 0.1" headers makes the unit huge (the point of breakouts) but defeats the purpose of this chip.
    It’s been a while since I checked SFE’s prototype tutorials. I think many would benefit from a tutorial on how to print layouts as a transparency then etch precise PCBs using pre-sensitized PCBs at home. 0.2mm line width can be achieved routinely using 1200 dpi printer and correct transparencies and printer settings. Having this capability opens up a whole new world to the home prototyper that doesn’t want to always send out PCBs to a fab house or wait a couple weeks.

  • if i use this LNA with a gps module that already have an inbuilt LNA then will it increase GPS sensitivity?

    • “It depends”. It could improve it, especially if you have a long cable to the antenna, but it could also make things worse (amplifiers amplify the noise as well). You’d really need to do a full RF circuit analysis to tell for sure, which isn’t trivial.

  • SOT666 is rather unfortunate name for a package.

  • Wow, awesome!
    Any chance of getting a breakout board for this? I don’t want to cough/sneeze/breath and see this thing disappear :)

  • I notice that they say the gerbers for the ST breakout board are available upon request. I note, however, that it’s a multi-layer board.

  • Another vote for a breakout board .. Please!

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