TOBY-L4 series - System Integration Manual
UBX-16024839 - R04
Design-in
Page 52 of 143
2
Design-in
2.1
Overview
For optimal integration of the modules in the application PCB, follow the design guidelines stated in this section.
Every application circuit must be properly designed to guarantee the correct functionality of the relative
interface, but a number of points require greater attention during the design of the application device.
The following list provides a rank of importance in the application design, starting with the most significant:
1.
Module antenna connection:
Antenna circuit directly affects the RF compliance of the device integrating a TOBY-L4 series module with
applicable certification schemes. Very carefully follow the suggestions provided in section 2.4 for the
schematic and layout design.
2.
Module supply:
The supply circuit affects the RF compliance of the device integrating a TOBY-L4 series module with
applicable required certification schemes as well as the antenna circuit design. Very carefully follow the
suggestions provided in section 2.2.1 for the schematic and layout design.
3.
USB interface:
Accurate design is required to guarantee USB functionality. Carefully follow the suggestions provided in
section 2.6.1 for the schematic and layout design.
4.
SIM interface:
Accurate design is required to guarantee SIM card functionality reducing the risk of RF coupling. Carefully
follow the suggestions provided in section 2.5 for the schematic and layout design.
5.
System functions:
Accurate design is required to guarantee well defined voltage level during operation at Reset and Power-on
inputs. Carefully follow the suggestions provided in section 2.3 for the schematic and layout design.
6.
Analog audio:
Accurate design is required to obtain clear and high quality audio reducing the risk of noise from audio lines
due to both supply burst noise coupling and RF detection. Carefully follow the suggestions provided in
section 2.8.1 for the schematic and layout design.
7.
SDIO, RGMII, eMMC interfaces:
Accurate design is required to guarantee SDIO, RGMII, eMMC interfaces functionality. Carefully follow the
suggestions provided in section 2.6.5, 2.6.6, 2.7 for the schematic and layout design.
8.
ADC interfaces:
Accurate design is required to guarantee ADC interfaces functionality. Carefully follow the suggestions
provided in section 2.9 for the schematic and layout design.
9.
Other digital interfaces: (UART, SPI, I
2
C, I
2
S, Host Select, GPIOs, and Reserved pins).
Accurate design is required to guarantee correct functionality and reduce the risk of digital data frequency
harmonics coupling. Follow the suggestions provided in sections 2.6.1, 2.6.3, 2.6.4, 2.8.2, 2.3.3, 2.10, 2.11.
10.
Other supplies:
V_BCKP
RTC supply and
V_INT
generic digital interfaces supply.
Correct design is required to guarantee functionality. Follow the suggestions provided in 2.2.2 and 2.2.3.
It is recommended to also follow the specific design guidelines provided by each manufacturer of any
external part selected for the application board that integrates the u-blox cellular modules.
