NX15 LGA Pad Layout
This page explains the main LGA pad groups used when integrating the NX15 module into a custom PCB.
Use this page together with the official pad layout drawing before finalizing the PCB footprint.
Always verify the latest pad layout and recommended landing pattern before PCB release.
Module Package Summary
| Item | Value |
|---|---|
| Package type | LGA surface-mount module |
| Module body | 9.5 × 9.5 mm |
| Height | 1.95 mm with shield |
| Pad pitch | 0.65 mm |
| Mounting | SMT reflow |
Main Pad Groups
| Pad Group | Purpose |
|---|---|
| VDD_nRF | Main supply input |
| GND | Ground, RF reference, and thermal return path |
| SWDIO / SWDCLK | Programming and debugging |
| NRESET | Active-low reset |
| GPIO | General-purpose I/O and peripheral mapping |
| Analog input pins | SAADC / analog sensing |
| NFC pins | NFC antenna interface or GPIO, depending on firmware |
| XL1 / XL2 | 32.768 kHz crystal pins or GPIO |
| SWO | Debug trace or GPIO |
VDD_nRF Pads
| Item | Recommendation |
|---|---|
| Function | Main supply input |
| Voltage | 1.7–3.6 V |
| Decoupling | Place 100 nF + 1 µF capacitors close to each VDD pad |
| Routing | Keep power path short and stable |
| Test | Add VDD test point for bring-up |
GND Pads
GND pads are used for common ground, RF reference, and thermal return path.
| Rule | Recommendation |
|---|---|
| Connect all GND pads | Do not leave any GND pad floating |
| Via stitching | Use short vias to solid ground plane |
| Ground plane | Keep ground plane continuous below the module |
| RF reference | Treat GND as part of RF performance, not only power return |
Poor GND connection can cause unstable firmware behavior, weak RF performance, or inconsistent current measurement.
SWD and Reset Pads
| Signal | Purpose | Recommendation |
|---|---|---|
| SWDIO | Programming/debug data | Route to header or test pad |
| SWDCLK | Programming/debug clock | Route to header or test pad |
| NRESET | Active-low reset | Route to reset button, header, or test pad |
| SWO | Optional debug trace | Use only if debug trace is required |
Keep debug access available for development, recovery, and production programming.
GPIO Pads
GPIO pins can be mapped to different firmware functions.
| Function Type | Example Use |
|---|---|
| UART | Host communication or log output |
| SPI | External sensors or peripherals |
| I2C | Low-speed sensors or configuration devices |
| PWM | LED, buzzer, or control output |
| ADC | Analog sensor input |
| PDM | Digital microphone input |
| GPIO | Button, interrupt, enable, or status signal |
On Flash models, confirm whether QSPI-related pins are reserved before assigning them as GPIO.
Analog Input Pins
Analog-capable pins should be routed carefully.
| Design Item | Recommendation |
|---|---|
| Noise | Keep away from high-speed or switching signals |
| Protection | Add input protection if the signal leaves the PCB |
| Filtering | Add RC filter if required by the sensor |
| Voltage | Keep input within allowed voltage range |
NFC and Crystal Pins
Some pins can be used for special functions or GPIO, depending on the firmware configuration.
| Pin Group | Possible Use | Design Note |
|---|---|---|
| XL1 / XL2 | 32.768 kHz LFXO or GPIO | Reserve if external low-frequency crystal is required |
| NFC1 / NFC2 | NFC antenna or GPIO | Keep as NFC if NFC function is required |
| SWO | Debug trace or GPIO | Confirm firmware configuration before use |
PCB Footprint Checklist
Before releasing the PCB footprint:
| Check | Status |
|---|---|
| LGA pad pitch confirmed | ☐ |
| Recommended landing pattern followed | ☐ |
| All VDD pads connected correctly | ☐ |
| All GND pads connected to ground plane | ☐ |
| SWDIO / SWDCLK accessible | ☐ |
| NRESET accessible | ☐ |
| GPIO function checked against firmware | ☐ |
| Flash-model pin reservation checked | ☐ |
| Antenna area reviewed | ☐ |