Ublox SARA-R52 Series System Integration Manual
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Ublox SARA-R52 Series System Integration Manual

Lte-m/nb-iot modules based on ubx-r52 chipset
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SARA-R52 series
LTE-M / NB-IoT modules based on UBX-R52 chipset
System integration manual
Abstract
This document describes the features and the integration of the size-optimized SARA-R52 series
cellular modules, based on the latest u-blox UBX-R52 cellular chipset. The modules are specifically
designed for IoT, integrating an in-house developed cellular modem and A-GPS technology, and the
u-blox's leading M10 GNSS technology. The modules deliver high performance satellite positioning
alongside data connectivity in the very small and compact SARA form factor.
UBX-23004806 - R02
C1-Public
SARA-R52
www.u-blox.com

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Summary of Contents for Ublox SARA-R52 Series

  • Page 1 SARA-R52 Abstract This document describes the features and the integration of the size-optimized SARA-R52 series cellular modules, based on the latest u-blox UBX-R52 cellular chipset. The modules are specifically designed for IoT, integrating an in-house developed cellular modem and A-GPS technology, and the u-blox’s leading M10 GNSS technology.

  • Page 2: Document Information

    SARA-R52 series - System integration manual Document information Title SARA-R52 series Subtitle LTE-M / NB-IoT modules based on UBX-R52 chipset Document type System integration manual Document number UBX-23004806 Revision and date 16-Feb-2024 Disclosure restriction C1-Public Product status Corresponding content status...

  • Page 3: Table Of Contents

    SARA-R52 series - System integration manual Contents Document information ..........................2 Contents ................................3 System description ..........................6 1.1 Overview ................................ 6 1.2 Architecture ..............................8 1.3 Pin-out .................................10 1.4 Operating modes ............................15 1.5 Supply interfaces ............................16 1.5.1 Module supply input (VCC) ......................16 1.5.2 Generic digital interfaces supply output (V_INT) ...............19...
  • Page 4 2.10.2 Guidelines for GNSS RTC layout design ..................94 2.11 Reserved pin (RSVD) ..........................94 2.12 Module placement ............................94 2.13 Module footprint and paste mask ......................95 2.14 Schematic for SARA-R52 series module integration ................96 2.15 Design-in checklist ............................98 2.15.1 Schematic checklist .........................98 2.15.2 Layout checklist ..........................99 2.15.3 Antennas checklist ...........................99...
  • Page 5 SARA-R52 series - System integration manual 3.3.1 Soldering paste ..........................101 3.3.2 Reflow soldering ..........................101 3.3.3 Optical inspection .......................... 102 3.3.4 Cleaning ............................102 3.3.5 Repeated reflow soldering ......................103 3.3.6 Wave soldering ..........................103 3.3.7 Hand soldering ..........................103 3.3.8 Rework .............................

  • Page 6: System Description

    System description 1.1 Overview The SARA-R52 series LTE Cat M1 / NB2 modules are ideal solutions for IoT, in the miniature SARA LGA form factor (26.0 x 16.0 mm, 96-pin). They allow an easy integration into compact designs and a seamless drop-in migration from other u-blox cellular module families.
  • Page 7 SARA-R52 series - System integration manual SARA-R52 series modules include the following variants / product versions: • SARA-R520 LTE Cat M1 / NB2 module for multi regions, power-optimized to reach ultra-low power consumption in PSM / eDRX deep-sleep mode, integrating the u-blox SpotNow Assisted-GPS receiver technology with separate GPS antenna interface •...

  • Page 8: Architecture

    Figure 2: SARA-R520M10 module simplified block diagram ☞ The current products version of the SARA-R52 series modules do not support SPI and SDIO interfaces. They should be left unconnected and should not be driven by external devices. UBX-23004806 - R02...
  • Page 9 SARA-R52 series - System integration manual SARA-R52 series modules internally consist of the following sections, described with more details than the simplified block diagrams of Figure 1 Figure RF section Composed of the following main elements: • RF switch connecting the antenna port (ANT) to the suitable RF Tx / Rx paths for LTE Cat M1 / NB2 Half-Duplex operations •...

  • Page 10: Pin-Out

    SARA-R52 series - System integration manual 1.3 Pin-out Table 3 lists the pin-out of the SARA-R52 series modules, with pins grouped by function. Function Pin name Module Pin no. Description Remarks Power 51,52,53 I Module supply VCC supply circuit affects the RF...
  • Page 11 SARA-R52 series - System integration manual Function Pin name Module Pin no. Description Remarks VSIM SIM supply VSIM = 1.8 V / 3 V output as per the output connected SIM type. See section for functional description. See section for external circuit design-in.
  • Page 12 SARA-R52 series - System integration manual Function Pin name Module Pin no. Description Remarks UART data USIO variants 0 / 1: terminal ready Primary UART circuit 108/2 (DTR) in input / ITU-T V.24. AUX UART Internal active pull-up enabled. data input...
  • Page 13 SARA-R52 series - System integration manual Function Pin name Module Pin no. Description Remarks SDIO SDIO_D0 SDIO serial Alternatively configurable as SPI. data [0] SDIO not supported. SDIO_D1 SDIO serial Alternatively configurable as SPI. data [1] SDIO not supported. SDIO_D2 Alternatively configurable as SPI.
  • Page 14 Leave unconnected if not used or if clock is generated internally. Reserved RSVD SARA-R520 N/A Reserved pin Leave unconnected. See sections 1.15 and 2.11. Table 3: SARA-R52 series modules pin definition, grouped by function UBX-23004806 - R02 System description Page 14 of 119 C1-Public...

  • Page 15: Operating Modes

    The initial operating mode of SARA-R52 series modules is the not-powered mode: VCC supply is not present or below the operating range. The modules are switched off. Once a valid VCC supply is applied to the SARA-R52 series modules, the switch-on routine is triggered and the modules enter the active mode.

  • Page 16: Supply Interfaces

    GNSS activities. For eDRX cycles equal or longer than 327.68 s, the SARA-R52 series modules can enter the ultra-low power eDRX deep- sleep mode, out of the Paging Time Window (PTW).
  • Page 17 1.5.1.2 VCC current consumption in LTE connected mode During an LTE connection, the SARA-R52 series modules transmit and receive in half duplex mode. The current consumption depends on output RF power, which is always regulated by the network (the current base station) sending power control commands to the module. These power control commands are logically divided into a slot of 0.5 ms (time length of one Resource Block), thus the rate...
  • Page 18 (DRX) mode. Detailed current consumption values can be found in the SARA-R52 series data sheet [1]. Current [mA]...

  • Page 19: Generic Digital Interfaces Supply Output (V_Int)

    VCC main supply input of the module. The V_INT voltage regulator output of SARA-R52 series modules is disabled (i.e. 0 V) when the module is switched off, and it can be used to monitor the operating mode of the module as follows: •...

  • Page 20: Gnss Backup Supply Input (V_Bckp_Gnss)

    Applying a voltage at the VCC module supply input within the operating range (see SARA-R52 series data sheet [1]). When the SARA-R52 series modules are in the power-off mode (i.e. switched off, but with a valid voltage present at the VCC module supply input) or in deep-sleep mode, they can be switched on or they can be woken up as following: •...
  • Page 21 The module is ready to operate after all interfaces are configured. Start-up Module interfaces event are configured PWR_ON RESET_N V_INT Greeting ~2 s Figure 12: SARA-R52 series switch-on / early wake-up sequence description from power-off / deep-sleep mode UBX-23004806 - R02 System description Page 21 of 119 C1-Public...

  • Page 22: Module Power-Off

    Module power-off 1.6.2.1 Switch-off events The proper graceful power-off of the SARA-R52 series modules, with storage of the current parameter settings in the non-volatile memory of the module and a clean network detach, can be triggered by: • AT+CPWROFF command (see AT commands manual [2]) •...
  • Page 23 ☞ It is highly recommended to avoid an abrupt removal of the VCC supply during SARA-R52 series modules normal operations. An abrupt software reset, consisting in asserting the RESET_N input, must be preferred, if considered necessary (see section 1.6.2.3).

  • Page 24: Module Reset

    It is highly recommended to monitor the V_INT pin to sense the end of the switch-off sequence. ☞ The duration of each phase in the SARA-R52 series modules’ switch-off routines can largely vary, depending on the application / network settings and the concurrent module activities.
  • Page 25 Detailed electrical characteristics with voltages and timings are described in the SARA-R52 series data sheet [1]. SARA-R52 series Baseband processor RESET_N Reset Figure 15: SARA-R52 series RESET_N input equivalent circuit description UBX-23004806 - R02 System description Page 25 of 119 C1-Public...

  • Page 26: Antenna Interfaces

    1.7.1 Cellular antenna RF interface (ANT) SARA-R52 series modules provide an RF interface for connecting the external cellular antenna. The ANT pin represents the RF input/output for transmission and reception of LTE RF signals. The ANT pin has a nominal characteristic impedance of 50  and must be connected to the Tx / Rx cellular antenna through a 50 ...

  • Page 27: Gnss Antenna Rf Interface (Ant_Gnss)

    [17]; for additional information regarding SpotNow feature, see the SpotNow application note [19]. SARA-R52 series modules provide an RF interface for connecting the external GNSS antenna. The ANT_GNSS pin represents the RF input reception of GNSS RF signals.

  • Page 28: Cellular Antenna Detection Interface (Ant_Det)

    See the AT commands manual for more details on this feature. The ANT_DET pin generates a DC current (for detailed characteristics see the SARA-R52 series data sheet [1]) and measures the resulting DC voltage, thus determining the resistance from the antenna connector provided on the application board to GND.

  • Page 29: Data Communication Interfaces

    1.9.1.1 UART features SARA-R52 series modules include 1.8 V unbalanced asynchronous serial interfaces for communications with external host application processor. UART interfaces can be configured by AT commands (see the AT commands manual [2], +USIO AT command) in the following variants: •...
  • Page 30 The default frame format is 8N1 (8 data bits, no parity, 1 stop bit) SARA-R52 series modules are designed to operate as cellular modems, i.e. as the data circuit-terminating equipment (DCE) according to the ITU-T V.24 recommendation [5]. A host application processor connected to the module UART interface represents the data terminal equipment (DTE).
  • Page 31 SARA-R52 series modules’ UART interface is by default configured for AT commands: the module waits for AT command instructions and interprets all the characters received as commands to execute. All the functionalities supported by SARA-R52 series modules can be in general set and configured by AT commands: •...
  • Page 32 SARA-R52 series - System integration manual The different power saving configurations that can be set by the +UPSV AT command are described in detail in the following subsections. Table 8 summarizes the UART interface communication process in the different power saving configurations, in relation with HW flow control settings and RTS and DTR input lines status.
  • Page 33 SARA-R52 series - System integration manual AT+UPSV=0: power saving disabled, fixed active mode The module does not enter idle mode and the UART interface is enabled (data can be sent and received): the CTS line is always held in the ON state after UART initialization. This is the default configuration.
  • Page 34 SARA-R52 series - System integration manual The hardware flow control output (CTS line) indicates when the UART interface is enabled (data can be sent and received over the UART), if HW flow control is enabled, as illustrated in Figure 17: UART interface of the module is enabled when CTS is ON or low level;...
  • Page 35 SARA-R52 series - System integration manual When an OFF-to-ON transition occurs on the DTR input line, the UART is re-enabled and the module, if it was in idle mode, switches from idle to active mode after ~15 ms: this is the UART and module “wake-up time”.
  • Page 36 SARA-R52 series - System integration manual UART DCE UART is enabled for 2000 GSM frames (~9.2 s) time input Wake-up time: ~1 5 ms Wake-up character time Not recognized by DCE Figure 18: Wake-up via data reception without further communication Figure 19 shows the case where in addition to the wake-up character further valid characters are sent.

  • Page 37: Usb Interface

    1.9.1.4 UART multiplexer protocol SARA-R52 series modules include multiplexer functionality as per 3GPP TS 27.010 [8], on the UART physical link. This is a data link protocol which uses HDLC-like framing and operates between the module (DCE) and the application processor (DTE) and allows a number of simultaneous sessions over the used physical link (UART).

  • Page 38: Sdio Interface

    Communication with an external GNSS receiver is not supported by SARA-R520M10 modules. SARA-R52 series modules include a 1.8 V I2C-bus compatible interface over the SDA and SCL pins, available to communicate with an external u-blox GNSS receiver and/or with external I2C devices: the SARA-R52 series module acts as an I2C host that can communicate with I2C devices in accordance with the I2C bus specifications [10].

  • Page 39: General Purpose Input / Output (Gpio)

    SARA-R52 series - System integration manual 1.11 General purpose input / output (GPIO) SARA-R52 series modules include pins which can be configured as general purpose input/output or to provide custom functions via u-blox AT commands (for more details see AT commands manual...

  • Page 40: Cellular Antenna Dynamic Tuner Interface

    SARA-R52 series - System integration manual 1.12 Cellular antenna dynamic tuner interface SARA-R52 series modules include two output pins, RFCTRL1 and RFCTRL2, that can optionally be used to control in real time an external antenna tuning IC, as the two pins change their output value dynamically according to the specific current LTE band in use by the module.

  • Page 41: Design-In

    Design-in 2.1 Overview For an optimal integration of the SARA-R52 series modules in the final application board, follow the design guidelines stated in this section. Every application circuit must be suitably designed to ensure the correct functionality of the relative interface, but a number of points require greater attention during the design of the application device.

  • Page 42: Supply Interfaces

    (low impedance) connection to external ground can minimize power loss and improve RF and thermal performance. SARA-R52 series modules must be sourced through the VCC pins with a suitable DC power supply that should comply with the module VCC requirements summarized in...
  • Page 43 The selected regulator or battery must be able to support with adequate margin (e.g. at least twice) the highest averaged current consumption value specified in the SARA-R52 series data sheet [1]. The following sections highlight some design aspects for each of the supplies listed above providing...
  • Page 44 150 k resistor 0.1 W Step-down regulator 1 A 1 MHz TS30041 – Semtech Table 11: Components for the VCC supply circuit for SARA-R52 series modules, using a step-down regulator ☞ See the section 2.2.1.8, and in particular Figure 26...
  • Page 45 Table 12 show an example of a power supply circuit for SARA-R52 series modules, where the module VCC is supplied by an LDO linear regulator capable of delivering maximum peak / pulse current specified for LTE use-case, with suitable power handling capability.
  • Page 46 VCC pins must be capable of delivering the maximum current occurring during a transmission at maximum Tx power, as specified in SARA-R52 series data sheet [1]. The maximum discharge current is not always reported in the data sheets of batteries, but the maximum DC discharge current is typically almost equal to the battery capacity in Amp-hours divided by 1 hour.
  • Page 47 SARA-R52 series - System integration manual The battery charger IC, as linear charger, is more suitable for applications where the charging source has a relatively low nominal voltage (~5 V), so that a switching charger is suggested for applications where the charging source has a relatively high nominal voltage (e.g. ~12 V, see section 2.2.1.7...
  • Page 48 SARA-R52 series - System integration manual A power management IC should meet the following prerequisites to comply with the module VCC requirements summarized in Table • High efficiency internal step-down converter, with characteristics as indicated in section 2.2.1.2 • Low internal resistance in the active path Vout – Vbat, typically lower than 50 m...
  • Page 49 SARA-R52 series - System integration manual Using a battery pack with an internal NTC resistor, the MP2617H can monitor the battery temperature to protect the battery from operating under unsafe thermal conditions. Several parameters as the charging current, the charging timings, the input current limit, the input...
  • Page 50 SARA-R52 series - System integration manual 2.2.1.8 Additional guidelines for VCC supply circuit design To reduce voltage drops, use a low impedance power source. The series resistance of the supply lines (connected to the modules’ VCC and GND pins) on the application board and battery pack should also be considered and minimized: cabling and routing must be as short as possible to minimize losses.
  • Page 51 RF signal. This is more likely to happen with switching DC-DC converters, in which case it is better to select the highest operating frequency for the switcher and add a large L-C filter before connecting to the SARA-R52 series modules in the worst case.

  • Page 52: Generic Digital Interfaces Supply Output (V_Int)

    Generic digital interfaces supply output (V_INT) 2.2.2.1 Guidelines for V_INT circuit design SARA-R52 series modules provide the V_INT generic digital interfaces 1.8 V supply output, which can be mainly used to: • Indicate when the module is switched on and it is not in the deep-sleep mode or power-off mode •...

  • Page 53: Gnss Backup Supply Input (V_Bckp_Gnss)

    To make these features always available, connect an independent power supply to V_BCKP_GNSS to ensure backup domain supply when the internal u-blox M10 chipset is switched off, as in Figure V_BCKP_GNSS pin electrical characteristics are described in the SARA-R52 series data sheet [1]. SARA-R520M10 GNSS...

  • Page 54: System Functions Interfaces

    2.3.1.1 Guidelines for PWR_ON circuit design SARA-R52 series PWR_ON input is equipped with an internal active pull-up resistor; an external pull-up resistor is not required and should not be provided. If connecting the PWR_ON input to a push button, the pin will be externally accessible on the application device.

  • Page 55: Module Reset (Reset_N)

    2.3.2.1 Guidelines for RESET_N circuit design SARA-R52 series RESET_N is equipped with an internal active pull-up; an external pull-up resistor is not required and should not be provided. If connecting the RESET_N input to a push button, the pin will be externally accessible on the application device.

  • Page 56: Antenna Interfaces

    RESET_N pin as short as possible. 2.4 Antenna interfaces SARA-R52 series modules provide a cellular RF interface for connecting the external cellular antenna: the ANT pin represents the cellular RF input/output for cellular signals transmission and reception. SARA-R52 series modules provide also a GNSS RF interface for connecting the GNSS antenna: •...
  • Page 57 SARA-R52 series - System integration manual 2.4.1.2 Guidelines for RF transmission lines design Any RF transmission line, such as the ones from the ANT and ANT_GNSS pads up to the related antenna connector or up to the related internal antenna pad, must be designed so that the characteristic impedance is as close as possible to 50 .
  • Page 58 SARA-R52 series - System integration manual Additionally to the 50  impedance, the following guidelines are recommended for transmission lines: • Minimize the transmission line length: the insertion loss should be minimized as much as possible, in the order of a few tenths of a dB, •...
  • Page 59 SARA-R52 series - System integration manual 2.4.1.3 Guidelines for RF termination design The RF termination must provide a characteristic impedance of 50  as well as the RF transmission line up to the RF termination, to match the characteristic impedance of ANT and ANT_GNSS ports.

  • Page 60: Cellular Antenna Rf Interface (Ant)

    SARA-R52 series modules with all the applicable required certification schemes depends on antenna’s radiating performance.
  • Page 61 SARA-R52 series - System integration manual In both of cases, selecting external or internal antennas, these recommendations should be observed: • Select an antenna providing optimal return loss / VSWR / efficiency figure over all the operating cellular frequencies. •...
  • Page 62 SARA-R52 series - System integration manual Manufacturer Part number Product name Description AMOTECH AMMAL004 / Cellular SMD Antenna AMMAL008 699..960 MHz, 1710..2690 MHz 35.0 x 9.0 x 3.2 mm AMOTECH AMMAL021 / Cellular SMD Antenna AMMAL022 617..960 MHz, 1710..6000 MHz 39.0 x 9.0 x 3.2 mm...
  • Page 63 SARA-R52 series - System integration manual Table 20 lists some examples of possible external cellular antennas. Manufacturer Part number Part name Description Taoglas GSA.8835 Phoenix II 5G/4G Adhesive Mount Antenna, IP67-rated enclosure 600..6000 MHz 105 x 30 x 7.9 mm Taoglas GSA.8842...

  • Page 64: Gnss Antenna Rf Interface (Ant_Gnss)

    SARA-R52 series - System integration manual 2.4.3 GNSS antenna RF interface (ANT_GNSS) ☞ For additional information and guidelines regarding the GNSS design, see the positioning implementation application note [17]; for additional information regarding SpotNow feature, see the SpotNow application note [19].
  • Page 65 SARA-R52 series - System integration manual SARA-R52 series ANT_GNSS ANT_ON / GPIO8 Figure 38: Typical circuit for best performance and improved jamming immunity with GNSS passive antenna The external LNA can be selected to deliver the performance needed by the application in terms of: •...
  • Page 66 SARA-R52 series - System integration manual Table 22 lists examples of LNA. Manufacturer Part number Comments Maxim MAX2659ELT+ Low noise figure, up to 10 dBm RF input power JRC New Japan Radio NJG1143UA2 Low noise figure, up to 15 dBm RF input power...
  • Page 67 Higher protection level can be achieved by mounting an ultra-low capacitance (i.e. less than 1 pF) ESD protection (see Table 26) close to accessible point. Table 26 lists examples of ESD protection suitable for the GNSS RF input of SARA-R52 series modules. Manufacturer Part number Description ON Semiconductor ESD9R3.3ST5G...

  • Page 68: Cellular And Gnss Rf Coexistence

    SARA-R52 series - System integration manual Table 27 lists examples of active antennas. Manufacturer Part number Product name Description Tallysman TW3400 – TW3402 Active antenna, 2.5 – 16 V GPS / SBAS / QZSS / GLONASS Tallysman TW3710 – TW3712 Active antenna, 2.5 –...
  • Page 69 SARA-R52 series - System integration manual Jamming signals may come from in-band and out-band frequency sources. In-band jamming is caused by signals with frequencies falling within the GNSS frequency range, while out-band jamming is caused by very strong signals with frequencies adjacent to the GNSS frequency range so that part of the strong signal power may leak at the input of the GNSS receiver and/or block GNSS reception.
  • Page 70 Table 28: Examples of GNSS band-stop SAW filters Additional considerations As far as Tx power is concerned, SARA-R52 series modules maximum output power during LTE transmission is 23 dBm. High-power transmission occurs very infrequently: typical output power values are in the range of -3 to 0 dBm (see Figure 1 in the GSMA official document TS.09 [11]).

  • Page 71: Cellular Antenna Detection Interface (Ant_Det)

    SARA-R52 series - System integration manual 5.5 cm SARA GNSS module antenna Cellular antenna Figure 42: PCB top rendering for the u-blox B36 blueprint with annotated distance between cellular and GNSS antennas ☞ For additional information and guidelines regarding the GNSS design, see the positioning implementation application note [17].
  • Page 72 SARA-R52 series - System integration manual The antenna detection and diagnostic circuit suggested in Figure 43 Table 29 are here explained: • When antenna detection is forced by the +UANTR AT command (see AT commands manual [2]), the ANT_DET pin generates a DC current measuring the resistance (R2) from the antenna connector (J1) provided on the application board to GND.

  • Page 73: Cellular Antenna Dynamic Tuning Control Interface

    2.4.6 Cellular antenna dynamic tuning control interface SARA-R52 series modules support a wide range of frequencies, from 600 MHz to 2200 MHz. To provide more efficient antenna designs over a wide bandwidth, RFCTRL1 and RFCTRL2 pins can be configured to change their output value in real time according to the operating LTE band in use by the module.
  • Page 74 45(a), tuning the antenna impedance optimizes the power delivered into the antenna by dynamically adjusting the RF impedance seen by ANT pin of SARA-R52 series module. By creating a tuned matching network for each operating band, the total radiated power (TRP) and the total isotropic sensitivity (TIS) metrics are improved.

  • Page 75: Sim Interface

    SARA-R52 series - System integration manual 2.5 SIM interface 2.5.1 Guidelines for SIM circuit design 2.5.1.1 Guidelines for SIM cards, SIM connectors and SIM chips selection The ISO/IEC 7816, the ETSI TS 102 221 and the ETSI TS 102 671 specifications define the physical,...
  • Page 76 SARA-R52 series - System integration manual 2.5.1.2 Guidelines for single SIM card connection without detection A removable SIM card placed in a SIM card holder must be connected to the SIM card interface of SARA-R52 series modules as described in...
  • Page 77 Guidelines for single SIM chip connection A Surface-Mounted SIM chip (M2M UICC form factor) must be connected to the SIM card interface of the SARA-R52 series modules as described in Figure Follow these guidelines to connect the module to a Surface-Mounted SIM chip without SIM presence detection: •...
  • Page 78 SARA-R52 series - System integration manual • Connect one pin of the normally-open mechanical switch integrated in the SIM connector (as the SW2 pin in Figure 48) to the GPIO5 input pin, providing a weak pull-down resistor (e.g. 470 k, as...

  • Page 79: Guidelines For Sim Layout Design

    The layout of the SIM card interface lines (VSIM, SIM_CLK, SIM_IO, SIM_RST) may be critical if the SIM card is placed far away from the SARA-R52 series modules or in close proximity to the cellular antenna and/or GNSS antenna: these two cases should be avoided or at least mitigated as described below.

  • Page 80: Data Communication Interfaces

    SARA-R52 series - System integration manual 2.6 Data communication interfaces 2.6.1 UART interfaces 2.6.1.1 Guidelines for UART circuit design Providing 1 UART with the full RS-232 functionality (using the complete V.24 link) ☞ Compatible with USIO variant 1; not compatible with USIO variants 0/2/3/4 (see section 1.9.1.1).
  • Page 81 SARA-R52 series - System integration manual ☞ Provide accessible test points directly connected to TXD and RXD pins for FW update purpose; accessible test points may be provided to DCD and DTR pins for diagnostic purposes, alternatively to the highly recommended test points on the USB interface pins.
  • Page 82 SARA-R52 series - System integration manual ☞ Provide accessible test points directly connected to TXD and RXD pins for FW update purpose; accessible test points may be provided to DCD and DTR pins for diagnostic purposes, alternatively to the highly recommended test points on the USB interface pins.
  • Page 83 SARA-R52 series - System integration manual ☞ Provide accessible test points directly connected to TXD and RXD pins for FW update purpose; accessible test points may be provided to DCD and DTR pins for diagnostic purposes, alternatively to the highly recommended test points on the USB interface pins.
  • Page 84 SARA-R52 series - System integration manual Providing 1 UART with the TXD and RXD lines only ☞ Compatible with USIO variants 0/1/3; not compatible with USIO variants 2/4 (see section 1.9.1.1). ☞ Providing the TXD and RXD lines only is not recommended if the multiplexer functionality is used in the application: providing also at least the HW flow control (RTS and CTS lines) is recommended, and it is particularly necessary if the low power mode is enabled by +UPSV AT command.
  • Page 85 SARA-R52 series - System integration manual Providing 2 UARTs with the TXD and RXD lines only ☞ Compatible with USIO variants 2/3/4; not compatible with USIO variants 0/1 (see section 1.9.1.1). ☞ Providing the TXD and RXD lines only is not recommended if the multiplexer functionality is used in the application: providing also at least the HW flow control (RTS and CTS lines) is recommended, and it is in particular necessary if the low power mode is enabled by +UPSV AT command.
  • Page 86 SARA-R52 series - System integration manual Additional considerations If a 3.0 V application processor (DTE) is used, the voltage scaling from any 3.0 V output of the DTE to the corresponding 1.8 V input of the module (DCE) can be implemented, as an alternative low-cost solution, by an appropriate voltage divider.

  • Page 87: Usb Interface

    Figure 2.6.3 SPI interface ☞ The SPI interface is not supported by current SARA-R52 series products version, except for diagnostic purposes. ☞ Accessible test points directly connected to the SDIO_D0, SDIO_D1, SDIO_D2 and SDIO_D3 pins may be provided for diagnostic purposes, alternatively to the highly recommended test points on the USB interface pins.

  • Page 88: Sdio Interface

    SARA-R52 series - System integration manual 2.6.4 SDIO interface ☞ The SDIO interface is not supported by current SARA-R52 series products version, except for diagnostic purposes. ☞ Accessible test points directly connected to the SDIO_D0, SDIO_D1, SDIO_D2 and SDIO_D3 pins may be provided for diagnostic purposes, alternatively to the highly recommended test points on the USB interface pins.
  • Page 89 SARA-R52 series - System integration manual u-blox GNSS SARA-R520 GNSS LDO 1.8 V receiver VMAIN regulator GNSS supply enable GPIO2 SHDN GNSS data ready GPIO3 GNSS time stamp GPIO4 EXTINT GNSS time pulse TIMEPULSE SDIO_CMD Figure 62: Application circuit for connecting SARA-R520 modules to a u-blox 1.8 V GNSS receiver...
  • Page 90 SARA-R52 series - System integration manual u-blox GNSS SARA-R520 3.0 V receiver VMAIN LDO regulator GNSS supply enable GPIO2 SHDN I2C-bus bidirectional voltage translator V_INT VCCB VCCA SDA_B SDA_A SCL_B SCL_A Unidirectional voltage translator VCCA VCCB DIR1 DIR3 GNSS data ready...

  • Page 91: Adc

    SARA-R52 series - System integration manual 2.7 ADC SARA-R52 series modules include an analog-to-digital converter input pin, ADC, configurable via a dedicated AT command (for further details, see the AT commands manual [2]). 2.7.1 Guidelines for ADC circuit design As a design example, the ADC input pin can be connected to an external voltage divider for voltage...

  • Page 92: Guidelines For General Purpose Input/Output Layout Design

    ☞ Use transistors with at least an integrated resistor in the base pin or otherwise put a 10 k resistor on the board in series to the GPIO of SARA-R52 series modules. ☞ Do not apply voltage to any GPIO of the module before the switch-on of the GPIOs supply (V_INT), to avoid latch-up of circuits and allow a clean module boot.

  • Page 93: Gnss Real-Time Clock

    Table 43. The external clock signal must always be available to allow the receiver to perform a periodical offset calibration for the RTC clock. Detailed RTC_GNSS pin electrical characteristics are described in the SARA-R52 series data sheet [1]. SARA-R520M10 CLKOUT...

  • Page 94: Guidelines For Gnss Rtc Layout Design

    ☞ The heat dissipation during continuous transmission at maximum power can raise the temperature of the application baseboard below the SARA-R52 series modules: avoid placing temperature sensitive devices close to the module. UBX-23004806 - R02...

  • Page 95: Module Footprint And Paste Mask

    Stencil: 1 50 H’ H’’ µm J’ J’’ F’ F’’ F’ F’’ Figure 69: SARA-R52 series modules suggested footprint and paste mask (application board top view) Parameter Value Parameter Value Parameter Value 26.0 mm 1.10 mm 2.75 mm 16.0 mm H’...

  • Page 96: Schematic For Sara-R52 Series Module Integration

    SARA-R52 series - System integration manual 2.14 Schematic for SARA-R52 series module integration Figure 70 is an example schematic diagram where a SARA-R520 module is integrated into an application board using most of the available interfaces and functions of the module.
  • Page 97 SARA-R52 series - System integration manual Figure 71 is an example schematic diagram where a SARA-R520M10 module is integrated into an application board using most of the available interfaces and functions of the module. SARA-R520M10 Cellular antenna Matching circuit depends on...

  • Page 98: Design-In Checklist

    Check UART signals direction, considering the modules’ signal names follow the ITU-T V.24 recommendation [5]. Provide accessible test points directly connected to the TXD and RXD pins of the SARA-R52 series modules for FW update purpose, in particular providing a 0  series jumper on each line to detach each pin of the module from the DTE application processor.

  • Page 99: Layout Checklist

    Optimize placement for minimum length of RF lines. Check the footprint and paste mask designed for SARA-R52 series module as illustrated in section 2.13. VCC line should be enough wide and as short as possible.

  • Page 100: Handling And Soldering

    The term is usually used in the electronics and other industries to describe momentary unwanted currents that may cause damage to electronic equipment. The ESD sensitivity for each pin of SARA-R52 series modules (as Human Body Model according to JESD22-A114F) is specified in the SARA-R52 series data sheet [1].

  • Page 101: Soldering

    3.3 Soldering 3.3.1 Soldering paste “No Clean” soldering paste is strongly recommended for SARA-R52 series modules, as it does not require cleaning after the soldering process has taken place. The paste listed in the example below meets these criteria. Soldering paste: OM338 SAC405 / Nr.143714 (Cookson Electronics)

  • Page 102: Optical Inspection

    SARA-R52 series - System integration manual Cooling phase A controlled cooling avoids negative metallurgical effects of the solder (solder becomes more brittle) and possible mechanical tensions in the products. Controlled cooling helps to achieve bright solder fillets with a good shape and low contact angle.

  • Page 103: Repeated Reflow Soldering

    Boards with combined through-hole technology (THT) components and surface-mount technology (SMT) devices require wave soldering to solder the THT components. No more than one wave soldering process is allowed for a board with a SARA-R52 series module already populated on it. ⚠...

  • Page 104: Grounding Metal Covers

    SARA-R52 series - System integration manual 3.3.11 Grounding metal covers Attempts to improve grounding by soldering ground cables, wick or other forms of metal strips directly onto the EMI covers is done at the customer’s own risk. The numerous ground pins should be sufficient to provide optimum immunity to interference and noise.

  • Page 105: Approvals

    Verizon Wireless network operator in United States ▪ The manufacturer of the end-device that integrates a SARA-R52 series module must take care of all certification approvals required by the specific integrating device to be deployed in the market. The required certification scheme approvals and relative testing specifications applicable to the...

  • Page 106: Federal Communications Commission Notice

    ⚠ Manufacturers of mobile or fixed devices incorporating SARA-R52 series modules are authorized to use the FCC Grants of the SARA-R52 series modules for their own final host products according to the conditions referenced in the certificates. UBX-23004806 - R02...

  • Page 107: Innovation, Science, Economic Development Canada Notice

    Manufacturers of mobile or fixed devices incorporating SARA-R52 series modules are authorized to use the FCC Grants of the SARA-R52 series modules for their own final host products if, as per FCC KDB 996369, the antenna trace design implemented on the host PCB is electrically equivalent to the antenna trace design implemented on the u-blox host PCB used for regulatory type approvals of the SARA-R52 series modules.

  • Page 108: Modifications

    Listing (new application) procedure followed by an ISED Class IV Permissive Change application. ⚠ If the ISED Certificates of the SARA-R52 series modules can be used for the final host product, as the conditions above are met, the ISED Label of the module shall be visible from the outside, or the host device shall bear a second label stating: “Contains IC: 8595A-UBX19KM01”...
  • Page 109 ⚠ IMPORTANT: Manufacturers of portable applications incorporating the SARA-R52 series modules are required to have their final product certified and apply for their own Industry Canada Certificate related to the specific portable device. This is mandatory to meet the SAR requirements for portable devices.

  • Page 110: European Conformance Ce Mark

    11.3 dBi in 1800 MHz, i.e. LTE FDD-3 band uplink 11.8 dBi in 2100 MHz, i.e. LTE FDD-1 band uplink The conformity assessment procedure for the SARA-R52 series modules, referred to in Article 17 and detailed in Annex II of Directive 2014/53/EU, has been followed.

  • Page 111: Acma Rcm Australia

    T D230041003 R 003-230096 The gain of the system antenna used for SARA-R52 series modules must not exceed 3 dBi to comply with Japan Technical Standard Conformity Certification (GITEKI Certification) requirements. Additionally, the antenna used in the end-device system for SARA-R52 series modules has to be listed on the technology conformity certified Antenna list of the related module.

  • Page 112: Product Testing

    Product testing 5.1 Validation testing and qualification SARA-R52 series modules are validated and tested by u-blox in the operating conditions and in certain integration, but not all the specific characteristics of the host application end-product integrating the module can be validated and tested by u-blox.

  • Page 113: Production Testing

    SARA-R52 series - System integration manual 5.2 Production testing 5.2.1 u-blox in-line production tests u-blox focuses on high quality for its products. All units produced are tested automatically in all their interfaces along the production line. Stringent quality control processes have been implemented in the production line.
  • Page 114 SARA-R52 series - System integration manual In addition, module AT commands can be used to perform functional tests on the digital interfaces. For example: • Communication with the host can be checked by AT command, • Communication with the SIM card/chip by the +CPIN read command, •...

  • Page 115: Appendix

    Appendix A Migration between SARA modules Guidelines to migrate from u-blox SARA-G3, SARA-G4, SARA-U2, SARA-N2, SARA-N3, SARA-R4 and SARA-R5 series modules to SARA-R52 series modules are available in the u-blox SARA modules migration guidelines application note [21]. B Glossary Abbreviation...
  • Page 116 SARA-R52 series - System integration manual Abbreviation Definition Firmware Galileo European satellite navigation system Global Certification Forum GLONASS GLObal Navigation Satellite System (Russian satellite navigation system) GNSS Global Navigation Satellite System GPIO General Purpose Input Output Global Positioning System Global System for Mobile communication...
  • Page 117 SARA-R52 series - System integration manual Abbreviation Definition Ring Indicator RSSI Received Signal Strength Indication RSVD Reserved Real Time Clock Request To Send Receiver SAIF Sub-meter-class Augmentation with Integrity Function Surface Acoustic Wave SBAS Satellite-Based Augmentation System SDIO Secure Digital Input Output...

  • Page 118: Related Documentation

    SARA-R52 series - System integration manual Related documentation u-blox SARA-R52 series data sheet, UBX-22038918 u-blox SARA-R5 series AT commands manual, UBX-19047455 u-blox EVK-SARA-R52 user guide, UBX-23006467 Universal Serial Bus revision 2.0 specification, https://www.usb.org/ ITU-T recommendation V.24 – 02-2000 – List of definitions for interchange circuits between Data Terminal Equipment (DTE) and Data Circuit-terminating Equipment (DCE), http://www.itu.int/rec/T-REC-V.24-200002-I/en...

  • Page 119: Contact

    SARA-R52 series - System integration manual Contact u-blox AG Address: Zürcherstrasse 68 8800 Thalwil Switzerland For further support and contact information, visit us at www.u-blox.com/support. UBX-23004806 - R02 Contact Page 119 of 119 C1-Public...

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