QUESTION

Question

To update our existing PCB to the M20048 here is what I believe needs to be done. It interfaces to a micro running at 3V3

1. Run supply directly off the micro rail (which is coming off a switcher supply). Could there be issues with noise?
2. Tuning pins 1 and 28 must be disconnected from 0V and connected to 0V via suitable resistor, cap etc
3. VBCK needs to be connected to 1.8V
4. ANT_OUT needs to be connected to ANT_IN via a capacitor.

Is there anything else I may have missed?

kind regards

Liam

Answer 1

Hello Hazeman,

The M20048 is not the direct replacement for the M10478. The M20050 is the direct replacement. Our product website has detailed instructions on upgrading to the new Radionova module.

Best regards,

Geoff S.

Comments

Hi,

 Because I never saw this until today we ended up fitting the M20048 in place. Performance was poor - slow TTFF, no satelite above 30dB.

 If we switch to the M20050 will we see an improvement (with default matching components)? I've order one to try this.

Could you tell me where the instructions are exactly please?

kind regards

Liam

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Hi Liam,

From a chipset standpoint, yes, the M20050 is a better GNSS engine. It states in the datasheet that: "The module can run three GNSS systems simultaneously to enhance location and TTFF considerably."

You can download the datasheet on our website here:

GPS/GNSS Receiver Module - Antenova

Best regards,

Geoff S.

Answer 2

Hi Liam,

Let me briefly answer your questions:

1. Yes, there can be issues with noise. Our datasheet comes with schematics to help you implement our GPS Module.

2.The tuning pins go straight to ground so yes, 0V is necessary.

3. The VBCK should be between 2.0 and 4.2VDC. Typical is 3.3VDC.

4. Yes, that is correct. There should be a capacitor between the ANT_OUT and ANT_IN.

You will be able to verify the schematic once you have it downloaded. There is some filtering on the TX and RX signal lines that is necessary.

Best regards,

Geoff S.

Comments

I've done some further tests on this.

All your points above have been followed and anti noise components changed to match example circuit.

Even when outside the case (bare PCB) I find the M20050 US satellites are 5-15dB down on our old M10478 design when run side by side.

We have a M20050 Eval PCB which gives levels about the same as the M10478.

Like I said before we've adapted one of our M10478 PCBs to take the M20050. This does leave a few orphaned tracks. I see about 40mV of noise on the GPS supply. I see the same on the M10478 though.

I think the adaptation resembles the circuit in the M20050 datasheet. I can you schematic and pictures if required.

I'm reaching the end of things to try. We don't want to design the M20050 in until confident it will work.

regards

Liam

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Hi Liam,

I think it may be time to have you send your board into use to evaluate. Can you contact our techsupport@antenova.com email and we can continue evaluating the differences in your design?

Best regards,

Geoff S.