u-blox SARA-R4 Series System Integration Manual

Contents

SARA-R4 series - System Integration ManualUBX-16029218 - R06 Design-inPage 34 of 1022 Design-in2.1 OverviewFor an optimal integration of SARA-R4 series modules in the final application board follow the design guidelinesstated in this section.Every application circuit must be properly designed to guarantee the correct functionality of the relativeinterface, however a number of points require high 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 connection: ANT and ANT_DET pins.Antenna circuit directly affects the RF compliance of the device integrating a SARA-R4 series module withapplicable certification schemes. Follow the suggestions provided in the relative section 2.4 for schematicand 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 withapplicable required certification schemes as well as antenna circuit design. Very carefully follow thesuggestions provided in the relative section 2.2.1 for schematic and layout design.3. USB interface: USB_D+, USB_D- and VUSB_DET pins.Accurate design is required to guarantee USB 2.0 high-speed interface functionality. Carefully follow thesuggestions provided in the relative section 2.6.2 for schematic and layout design.4. 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. Carefullyfollow the suggestions provided in the relative section 2.5 for schematic and layout design.5. System functions: RESET_N , PWR_ON pins.Accurate design is required to guarantee that the voltage level is well defined during operation. Carefullyfollow the suggestions provided in the relative section 2.3 for schematic and layout design.6. Other digital interfaces: UART, SPI, SDIO, I2C, I2S, GPIOs and Reserved pins.Accurate design is required to guarantee proper functionality and reduce the risk of digital data frequencyharmonics coupling. Follow the suggestions provided in sections 2.6.1, 2.6.2, 2.6.3, 2.6.4, 2.6.5, 2.7, 2.8and 2.9 for schematic and layout design.7. Other supplies: V_INT generic digital interfaces supply.Accurate design is required to guarantee proper functionality. Follow the suggestions provided in thecorresponding section 2.2.2 for schematic and layout design.It is recommended to follow the specific design guidelines provided by each manufacturer of any externalpart selected for the application board integrating the u-blox cellular modules.