SX1262 LoRa Matching Network Design

flux

For exact numeric values, I would not guess. The Semtech material I could access says the 915 MHz network is region-specific, that each region has its own BOM, and that the shown matching values may not be the most up to date; it also notes real designs usually need final tuning for PCB parasitics. That lines up with the rule to use the datasheet/reference design as the source of truth rather than memory
What I can say from the Semtech documentation:
Recommended starting point
  • For 902–928 MHz (US/Canada): start from the PCB_E428V03A SX1262 reference design.
  • For 915–928 MHz (Australia): start from the PCB_E449V01A SX1262 reference design.
Topology Semtech expects at 915 MHz
  • RX balun / impedance transform: 3-element network plus optional shunt part
  • TX match / harmonic filtering: multi-element network from RFO/VR_PA to antenna
  • Semtech gives these 915 MHz impedance targets in the note:
    • TX example load target: 11.7 + j4.8 Ω for max power, or 13.5 + j7.6 Ω for better efficiency
    • RX optimal differential source impedance: 74 + j134 Ω
In your schematic
Your U1 already has the right kind of external network, but the RF parts are still generic and don’t currently show values:
My recommendation
  • Use the Semtech 902–928 MHz SX1262 reference BOM values exactly as the first-spin starting point
  • Then expect to trim with:
    • VNA/S11 on the antenna port
    • conducted TX power / current
    • harmonic measurements
If you want, I can do one of these next:
  1. map your current RF network to the Semtech reference topology node-by-node, or
  2. help you find the exact 902–928 MHz BOM values from the reference schematic/BOM if you upload that PDF.
Map to reference
Upload reference BOM
Review RF layout
U4
https://cdn2.flux.ai/flux-comment-files/files/commentFileId-83692f5f84a9e3fb7cb4...
vasyl

vasyl

Image

Image

https://cdn2.flux.ai/flux-comment-files/files/commentFileId-83692f5f84a9e3fb7cb44cf67ade7905ebca3360ffc349fbf0171b761cbe23f1.svg?GoogleAccessId=706308333141-compute%40developer.gserviceaccount.com&Expires=4928102457&Signature=N0WVv2NB8eB%2BXXhCTGBzGi0RgbeNpjpqYtgIdMDlzX%2BaMQR6IzBE0BQlzkRlJ5%2BvAYMQ6OmSgGihPm0lVTn9Uc2cel%2F5xDcgTWkfmCCg2WNUVY3L1LPPybOnH5QiXO2qFI9n0zQBenIq%2BSzL3UFYDSpotJ%2BQLxczVcraRbvRCYz6gAR2m%2FvkyuYsDcQk1GS8s1booWyiYtm%2FMtCx7cND1Vii%2FqNbEPEa0SjBLvslw3uzYQLKu38y7SV%2BqOc%2B1sHM33jLSkNeRAgRRgQLJeere2MQKIriFHYCQirF3BKx69%2FDkAhLLGbkyJ9bMXd1aQETANJ8aXKrt9nOIeu%2FHfjjzA%3D%3D
4mo
Someone is typing...
2
BOOT
C37
Capacitance
100nF
Voltage
6.3V
C36
Capacitance
100nF
Voltage
6.3V
3V3
3V3
VDD_RF
S1
R6
Resistance
10KΩ
R17
Resistance
10KΩ
  • Generic Inductor
    Generic Inductor
    A generic fixed inductor suitable for rapid circuit topology development. The footprint automatically adapts based on the selected package, supporting standard SMD sizes (e.g., 0402, 0603, 0805) as well as well-known inductor packages such as SDR1806, PA4320, SRN6028, and SRR1260. Standard inductor values: 1.0 nH, 10 nH, 100 nH, 1.0 µH, 10 µH, 100 µH, 1.0 mH 1.2 nH, 12 nH, 120 nH, 1.2 µH, 12 µH, 120 µH, 1.2 mH 1.5 nH, 15 nH, 150 nH, 1.5 µH, 15 µH, 150 µH, 1.5 mH 1.8 nH, 18 nH, 180 nH, 1.8 µH, 18 µH, 180 µH, 1.8 mH 2.2 nH, 22 nH, 220 nH, 2.2 µH, 22 µH, 220 µH, 2.2 mH 2.7 nH, 27 nH, 270 nH, 2.7 µH, 27 µH, 270 µH, 2.7 mH 3.3 nH, 33 nH, 330 nH, 3.3 µH, 33 µH, 330 µH, 3.3 mH 3.9 nH, 39 nH, 390 nH, 3.9 µH, 39 µH, 390 µH, 3.9 mH 4.7 nH, 47 nH, 470 nH, 4.7 µH, 47 µH, 470 µH, 4.7 mH 5.6 nH, 56 nH, 560 nH, 5.6 µH, 56 µH, 560 µH, 5.6 mH 6.8 nH, 68 nH, 680 nH, 6.8 µH, 68 µH, 680 µH, 6.8 mH 8.2 nH, 82 nH, 820 nH, 8.2 µH, 82 µH, 820 µH, 8.2 mH #generics #CommonPartsLibrary
    jharwinbarrozo
    16.7k
  • Generic Capacitor
    Generic Capacitor
    A generic fixed capacitor ideal for rapid circuit topology development. You can choose between polarized and non-polarized types, its symbol and the footprint will automatically adapt based on your selection. Supported options include standard SMD sizes for ceramic capacitors (e.g., 0402, 0603, 0805), SMD sizes for aluminum electrolytic capacitors, and through-hole footprints for polarized capacitors. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard capacitor values: 1.0pF, 10pF, 100pF, 1000pF, 0.01uF, 0.1uF, 1.0uF, 10uF, 100uF, 1000uF, 10000uF 1.1pF, 11pF, 110pF, 1100pF 1.2pF, 12pF, 120pF, 1200pF 1.3pF, 13pF, 130pF, 1300pF 1.5pF, 15pF, 150pF, 1500pF, 0.015uF, 0.15uF, 1.5uF, 15uF, 150uF, 1500uF 1.6pF, 16pF, 160pF, 1600pF 1.8pF, 18pF, 180pF, 1800pF 2.0pF, 20pF, 200pF, 2000pF 2.2pF, 22pF, 220pF, 2200pF, 0.022uF, 0.22uF, 2.2uF, 22uF, 220uF, 2200uF 2.4pF, 24pF, 240pF, 2400pF 2.7pF, 27pF, 270pF, 2700pF 3.0pF, 30pF, 300pF, 3000pF 3.3pF, 33pF, 330pF, 3300pF, 0.033uF, 0.33uF, 3.3uF, 33uF, 330uF, 3300uF 3.6pF, 36pF, 360pF, 3600pF 3.9pF, 39pF, 390pF, 3900pF 4.3pF, 43pF, 430pF, 4300pF 4.7pF, 47pF, 470pF, 4700pF, 0.047uF, 0.47uF, 4.7uF, 47uF, 470uF, 4700uF 5.1pF, 51pF, 510pF, 5100pF 5.6pF, 56pF, 560pF, 5600pF 6.2pF, 62pF, 620pF, 6200pF 6.8pF, 68pF, 680pF, 6800pF, 0.068uF, 0.68uF, 6.8uF, 68uF, 680uF, 6800uF 7.5pF, 75pF, 750pF, 7500pF 8.2pF, 82pF, 820pF, 8200pF 9.1pF, 91pF, 910pF, 9100pF #generics #CommonPartsLibrary
    jharwinbarrozo
    1.5M
  • Generic Resistor
    Generic Resistor
    A generic fixed resistor ideal for rapid circuit topology development. Its footprint automatically adapts based on the selected package case code—supporting 0402, 0603, 0805, 1203, and many other standard SMD packages, as well as axial horizontal and vertical configurations. Save precious design time by seamlessly add more information to this part (value, footprint, etc.) as it becomes available. Standard resistor values: 1.0 ohm, 10 ohm, 100 ohm, 1.0k ohm, 10k ohm, 100k ohm, 1.0M ohm 1.1 ohm, 11 ohm, 110 ohm, 1.1k ohm, 11k ohm, 110k ohm, 1.1M ohm 1.2 ohm, 12 ohm, 120 ohm, 1.2k ohm, 12k ohm, 120k ohm, 1.2M ohm 1.3 ohm, 13 ohm, 130 ohm, 1.3k ohm, 13k ohm, 130k ohm, 1.3M ohm 1.5 ohm, 15 ohm, 150 ohm, 1.5k ohm, 15k ohm, 150k ohm, 1.5M ohm 1.6 ohm, 16 ohm, 160 ohm, 1.6k ohm, 16k ohm, 160k ohm, 1.6M ohm 1.8 ohm, 18 ohm, 180 ohm, 1.8K ohm, 18k ohm, 180k ohm, 1.8M ohm 2.0 ohm, 20 ohm, 200 ohm, 2.0k ohm, 20k ohm, 200k ohm, 2.0M ohm 2.2 ohm, 22 ohm, 220 ohm, 2.2k ohm, 22k ohm, 220k ohm, 2.2M ohm 2.4 ohm, 24 ohm, 240 ohm, 2.4k ohm, 24k ohm, 240k ohm, 2.4M ohm 2.7 ohm, 27 ohm, 270 ohm, 2.7k ohm, 27k ohm, 270k ohm, 2.7M ohm 3.0 ohm, 30 ohm, 300 ohm, 3.0K ohm, 30K ohm, 300K ohm, 3.0M ohm 3.3 ohm, 33 ohm, 330 ohm, 3.3k ohm, 33k ohm, 330k ohm, 3.3M ohm 3.6 ohm, 36 ohm, 360 ohm, 3.6k ohm, 36k ohm, 360k ohm, 3.6M ohm 3.9 ohm, 39 ohm, 390 ohm, 3.9k ohm, 39k ohm, 390k ohm, 3.9M ohm 4.3 ohm, 43 ohm, 430 ohm, 4.3k ohm, 43K ohm, 430K ohm, 4.3M ohm 4.7 ohm, 47 ohm, 470 ohm, 4.7k ohm, 47k ohm, 470k ohm, 4.7M ohm 5.1 ohm, 51 ohm, 510 ohm, 5.1k ohm, 51k ohm, 510k ohm, 5.1M ohm 5.6 ohm, 56 ohm, 560 ohm, 5.6k ohm, 56k ohm, 560k ohm, 5.6M ohm 6.2 ohm, 62 ohm, 620 ohm, 6.2k ohm, 62K ohm, 620K ohm, 6.2M ohm 6.8 ohm, 68 ohm, 680 ohm, 6.8k ohm, 68k ohm, 680k ohm, 6.8M ohm 7.5 ohm, 75 ohm, 750 ohm, 7.5k ohm, 75k ohm, 750k ohm, 7.5M ohm 8.2 ohm, 82 ohm, 820 ohm, 8.2k ohm, 82k ohm, 820k ohm, 8.2M ohm 9.1 ohm, 91 ohm, 910 ohm, 9.1k ohm, 91k ohm, 910k ohm, 9.1M ohm #generics #CommonPartsLibrary
    jharwinbarrozo
    1.5M
  • Terminal
    Terminal
    An electrical connector acting as reusable interface to a conductor and creating a point where external circuits can be connected.
    natarius
  • RMCF0805JT47K0
    RMCF0805JT47K0
    General Purpose Thick Film Standard Power and High-Power Chip Resistor 47 kOhms ±5% 0.125W, 1/8W Chip Resistor 0805 (2012 Metric) Automotive AEC-Q200 Thick Film Features: - RMCF – standard power ratings - RMCP – high power ratings - Nickel barrier terminations standard - Power derating from 100% at 70ºC to zero at +155ºC - RoHS compliant, REACH compliant, and halogen free - AEC-Q200 compliant
    jharwinbarrozo
    1.2M
  • 875105359001
    875105359001
    10 µF 16 V Aluminum - Polymer Capacitors Radial, Can - SMD 30mOhm 2000 Hrs @ 105°C #commonpartslibrary #capacitor #aluminumpolymer #radialcan
    jharwinbarrozo
    1.2M
  • CTL1206FYW1T
    CTL1206FYW1T
    Yellow 595nm LED Indication - Discrete 1.7V 1206 (3216 Metric)
    jharwinbarrozo
    1.1M
  • 1070TR
    1070TR
    Battery Holder (Open) Coin, 20.0mm 1 Cell SMD (SMT) Tab bate or batt #forLedBlink
    jharwinbarrozo
    700.5k
  • Push Button
    Push Button
    A momentary or non-latching switch which causes a temporary change in the state of an electrical circuit only while the switch is physically actuated. SWITCH TACTILE SPST-NO 0.05A 24V
    jharwinbarrozo
    490.7k
  • T491D226K025AT
    T491D226K025AT
    22 µF Molded Tantalum Capacitors 25 V 2917 (7343 Metric) 800mOhm #Capacitors #Tantalum #22uF #part
    vasyl
    448.3k

meshtastic

meshtastic thumbnail
Welcome to your new project. Imagine what you can build here.

Properties

Properties describe core aspects of the project.

Pricing & Availability

Distributor

Qty 1

Arrow

$7.09–$10.66

Digi-Key

$9.38–$14.48

LCSC

$11.98

Mouser

$15.41

TME

$2.43

Verical

$10.13–$18.56

Controls