SARA-R4 series - System integration manual
UBX-16029218 - R20
Design-in
Page 41 of 128
C1-Public
2
Design-in
2.1
Overview
For an optimal integration of the SARA-R4 series modules in the final application board, follow the
design guidelines stated in this section.
Every application circuit must be suitably designed to guarantee the correct functionality of the
relative interface, but a number of points require particular attention during the design of the
application device.
The following list provides a rank of importance in the application design, starting from the highest
relevance:
1.
Module antenna(s) connection:
ANT
,
ANT_GNSS
, and
ANT_DET
pins.
Cellular antenna circuit directly affects the RF compliance of the device integrating a SARA-R4
series module with applicable certification schemes. Follow the suggestions provided in the
relative section
for the schematic and layout design.
2.
Module supply:
VCC
and
GND
pins.
The supply circuit affects the RF compliance of the device integrating a SARA-R4 series module
with the applicable required certification schemes as well as the antenna circuit design. Very
carefully follow the suggestions provided in the relative section
for the schematic and layout
design.
3.
SIM interface:
VSIM
,
SIM_CLK
,
SIM_IO
,
SIM_RST
pins.
Accurate design is required to guarantee SIM card functionality reducing the risk of RF coupling.
Carefully follow the suggestions provided in relative section
for schematic and layout design.
4.
System functions:
RESET_N
and
PWR_ON
/
PWR_CTRL
pins.
Accurate design is required to guarantee that the voltage level is well defined during operation.
Carefully follow the suggestions provided in relative section
for schematic and layout design.
5.
USB interface:
USB_D+
,
USB_D-
and
VUSB_DET
/
USB_5V0
,
USB_3V3
pins.
Accurate design is required to guarantee USB 2.0 high-speed interface functionality. Carefully
follow the suggestions provided in the relative section
for the schematic and layout design.
6.
Other digital interfaces: UART, SPI, SDIO, I2C, I2S, GPIOs, GNSS PIOs 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
for the schematic and layout design.
7.
Other supplies:
V_INT
generic digital interfaces supply.
Accurate design is required to guarantee correct functionality. Follow the suggestions provided in
the corresponding section
for the schematic and layout design.
☞
It is recommended to follow the specific design guidelines provided by each manufacturer of any
external part selected for the application board integrating the u-blox cellular modules.
