GPS Module - Venus638FLPx-L 20Hz (14 Channel)

Venus638FLPx is a high performance, low cost, single chip GPS module targeting mobile consumer and cellular handset applications. It offers very low power consumption, high sensitivity, and best in class signal acquisition and time-to-first-fix performance.

Venus638FLPx contains all the necessary components of a complete GPS module, includes 1.2dB cascaded system NF RF front-end, GPS baseband signal processor, 0.5ppm TCXO, 32.768kHz RTC crystal, RTC LDO regulator, and passive components. It requires very low external component count and takes up only 100mm2 PCB footprint.

Not sure which GPS module is right for you? Check out our GPS Buying Guide!

Note: According to the manufacturer's specifications, the IC requires a 24 hour pre-bake at 125C before SMD mounting in order to prevent issues with moisture .


  • -148dBm cold start sensitivity
  • -165dBm tracking sensitivity
  • 29 second cold start TTFF
  • 3.5 second TTFF with AGPS
  • 1 second hot start
  • 2.5m accuracy
  • Multipath detection and suppression
  • Jamming detection and mitigation
  • SBAS (WAAS / EGNOS) support
  • 67mW full power navigation
  • Works directly with active or passive antenna
  • Internal flash for optional 75K point data logging
  • Supports external SPI flash memory data logging
  • Complete receiver in 10mm x 10mm x 1.3mm size
  • Contains LNA, SAW Filter, TCXO, RTC Xtal, LDO
  • 10 x 10 x 1.3mm, LGA69 package


GPS Module - Venus638FLPx-L 20Hz (14 Channel) Product Help and Resources

Core Skill: Soldering

This skill defines how difficult the soldering is on a particular product. It might be a couple simple solder joints, or require special reflow tools.

3 Soldering

Skill Level: Competent - You will encounter surface mount components and basic SMD soldering techniques are required.
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Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
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Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

4 Electrical Prototyping

Skill Level: Experienced - You will need to consult a datasheet for calculations to determine a components output format, linearity, and do a little math to get what you need. You will be using a datasheet or schematic beyond basic pinouts.
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Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • Ericp / about 13 years ago / 3

    When can we expect to see a dev board with this chip on it now that the Venus634 is retired?

    • spencerogden / about 13 years ago / 1

      Agree, very eager for a dev board like the GPS-09133.

  • signal7 / about 13 years ago / 2

    24 hours at 125C? That can't be right. I don't think anyone would want to prebake for that long if they were doing production.
    Atmel, for instance, ships their moisture sensitive parts in sealed bags to prevent that issue. I don't recall the atmel part number (attiny24 maybe), but every one I received was individually vacuum packed with an indicator card so you'd know if you needed to prebake it or not. Even so, the prebake period is fairly short.
    Just curious...

    • MikeGrusin / about 13 years ago * / 1

      The entire statement in the datasheet is:

      Like BGA device, the Venus638FLPx is moisture sensitive. It needs to be handled with care to void damage from moisture absorption and SMT re-flow. The device should be baked for 24 hours at 125-degC before mounting for SMT re-flow if it has been removed from the protective seal for more than 48* hours.
      *Actual (hours) will be longer, moisture sensitivity level still undergoing verification.

      • TRF / about 13 years ago /

        OK, but note that in the part description you write 125C, not 25C.

        • MikeGrusin / about 13 years ago /

          Sorry, I mangled the quote (now fixed), it does state 125C in the datasheet.

  • Scotty / about 13 years ago / 2

    The photos of your IC and the IC in the datasheet look different. Could you please clairify and let us know which one is correct and which pinout to use. Thanks.

    • Itai N / about 13 years ago / 1

      You are probably right. The photo is of a LGA44 package (possibly the older Venus634FLPx) and this is a LGA69 package.
      The Venus638FLPx-L is a drop-in replacement of the Venus634FLPx, but some new functions require use of the new pins.

      • MikeGrusin / about 13 years ago /

        These are older photos of the 634, we'll update them soon. The 638 has the same footprint as the 634 with the addition of BGA-style pads beneath the chip. Use the layout in the datasheet.

        • Scotty / about 13 years ago /

          Do you have an eagle footprint or any recommendations on accessing these pads underneath?

          • MikeGrusin / about 13 years ago * /

            The footprint is in the SFE library (VENUS638FLPX-L), but it hasn't been proven yet.

            • Scotty / about 13 years ago * / 1

              Do you think adding vias underneath would be able to access these pads? Sorry but I'm just trying to make my own GPS logger...

              • MikeGrusin / about 13 years ago / 1

                Two things: 1. yes, vias would be the only way to access the pads beneath the chip. 2. After talking with the manufacturer, it appears that the additional ports underneath the chip are only enabled if you write custom code for the chip. The stock firmware does not access them.

  • rl / about 9 years ago / 1

    Does anyone know if it's possible to communicate with this receiver via SPI or I2C instead of UART?

  • Member #528293 / about 10 years ago / 1

    Hi everyone. I have a question about active antenna. In datasheet is shown that active antenna is hooked up to power supply 3.3V and connected to input pin RFIN pin. I need to use an active antenna with power supply 5V. Is the RFIN pin 5V tolerant?

  • Ricozinn / about 10 years ago / 1

    I'm having trouble sending any commands to my receiver. I am using the FTDI serial converter, and connecting it to the board I can receive all the NMEA messages and see it acquire satellites and such, but whenever I try and send a command (like reset, or query version or whatever) it just hangs for a while then says it timed out. Any ideas?

    Anyone have some example C code to send a binary command to the receiver?


  • Member #121834 / about 11 years ago / 1

    I want to know if the chip is supplied with a preloaded firmware. If not, how can I download the firmware onto the chip?

  • Member #199945 / about 12 years ago / 1

    Has anyone been able to use the internal flash for data logging?? I have been trying to find any documentation about it but have not been very successful so far. Any help would be appreciated.

    • MikeGrusin / about 12 years ago / 1

      We're working on a tutorial for this, but in the meantime see the information at our Venus Breakout Board product page. Basically you use the GPS Viewer / Configuration Software to first load the internal logging firmware onto the Venus chip, and then use the same software to configure, start / stop, and download the internal log.

  • Member #335717 / about 12 years ago / 1

    What is a suitable evalution board for this module?

  • cyronin / about 12 years ago / 1

    The datasheet says that it is a 65 channel architecture, which is different from the product description. is there something that needs to be clarified

  • NerdyFirefighter / about 12 years ago / 1

    Does SF offer prebake services for those of us who are just using bench-top hot air stations to work with these?

Customer Reviews

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2 of 2 found this helpful:

Solid GPS chip

Using it in an autonomous sail boat project. Easy to setup and integrate. The low power standby is clutch.