Integration Manual

Table Of Contents
TOBY-L3 series - System Integration Manual
TSD-19090601 - R13 System Integration Manual Page 123 of 143
Check 50 nominal characteristic impedance of the RF transmission line connected to the ANT1
and the ANT2 ports (antenna RF interfaces).
Ensure no coupling occurs between the RF interface and noisy or sensitive signals (SIM signals,
high-speed digital lines such as the USB, SDIO, SGMII, eMMC, SPI and other data lines).
Optimize placement for minimum length of the RF line.
Check the footprint (copper mask), solder resist mask and stencil (paste mask) designed for TOBY-
L3 series modules as shown in section 2.13.
VCC line should be as wide and as short as possible.
Route VCC supply line away from RF lines / parts and other sensitive analog lines / parts.
The VCC bypass capacitors in the picoFarad range should be placed as close as possible to the VCC
pins, in particular if the application device integrates an internal antenna.
Ensure an optimal grounding connecting each GND pin with the application board solid ground
layer.
Use as many vias as possible to connect the ground planes on a multilayer application board,
providing a dense line of vias at the edges of each ground area, in particular along the RF and high
speed lines.
Keep routing short and minimize parasitic capacitance on the SIM lines to preserve signal integrity.
USB 2.0 data line traces must meet characteristic impedance requirements as per USB 2.0
specification [4], and should not be routed close to any RF line / part.
Keep the SDIO traces short, avoid stubs, avoid coupling with any RF line / part and consider low
value series damping resistors to avoid reflections and other losses in signal integrity.
Ensure appropriate RF precautions for the Wi-Fi and Cellular technologies coexistence.
Ensure appropriate RF precautions for the GNSS and Cellular technologies coexistence.
Route digital audio signals away from noisy sources (primarily RF interface, VCC, switching supplies).
The audio outputs lines on the application board must be wide enough to minimize series resistance.
2.15.3 Antenna checklist
Antenna termination should provide a 50 characteristic impedance with VSWR at least less than
3:1 (recommended 2:1) on operating bands in the deployment geographical area.
Follow the recommendations of the antenna producer for correct antenna installation and
deployment (PCB layout and matching circuitry).
Ensure compliance with any regulatory agency RF radiation requirement.
Ensure high and similar efficiency for both the primary (ANT1) and the secondary (ANT2) antennas.
Ensure high isolation between the primary (ANT1) and the secondary (ANT2) antennas.