Im working on a project where i want to implement the MAX-M10S GNSS onto a pcb, but i noticed in the schematic R14 and C1 have no value. What value should these be?
After a bit of digging in the data sheet, it looks like R14 should be 10 Ω, and C1 should be 10 nF.
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R14 typically 10R to limit current
C1 10nF
RF blocking inductor, 27 nH, 5% Murata LQG15H, LQW15A series Johanson Technology L-07W series. Any other inductor with impedance >500 Ω at GNSS frequency and current rating above 300 mA.
Most active antenna these days are around 10 - 35mA
I’d avoid Coilcraft SMT inductors, bunch of headaches here with those disintegrating.
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A little strange they didn’t just say that on the schematic.
Some places do part selection at the BoM level, and don’t constantly back-annotate into the schematic. Especially true when one schematic has a dozen build options.
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We use R4 = 33 and C1 = 47pF. In retrospect, R4 should indeed be lower, 10 Ohm is great.
A little strange they didn’t just say that on the schematic.
Oversight on our part.
Some places do part selection at the BoM level, and don’t constantly back-annotate into the schematic.
That, but at the test-out phase. We needed the flexibility during the test phase, locked it in, but then failed to go back and update the schematic. Sorry!
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