B404X Datasheet

This is a graphic of the B404. The B404X has the same exterior dimensions but the appearance may vary slightly from this graphic.

Functional description

Overview

The B-Series System-on-a-Module (SoM) is a cellular device with support for BLE (Bluetooth LE). It is based on the Nordic nRF52840 microcontroller.

The B-Series is designed to be integrated into your circuit board design, plugging into a M.2 NGFF connector on your board, allowing the module to be changed or upgraded easily.

Features

Features - B404X

• u-blox SARA-R510S-01B LTE modem (B404X)
  • LTE Cat M1 module
  • Support for United States, Canada, and Mexico only
  • 3GPP Release 14 LTE Cat M1
  • LTE Cat M1 bands: 2, 4, 5, 12, 13
  • Embedded Particle EtherSIM (B404X)
  • Requires Device OS 4.0.0 LTS (or later)

Features - all models

• Nordic Semiconductor nRF52840 SoC
  • ARM Cortex-M4F 32-bit processor @ 64MHz
  • 1MB flash, 256KB RAM
  • Bluetooth 5: 2 Mbps, 1 Mbps, 500 Kbps, 125 Kbps
  • Supports DSP instructions, HW accelerated Floating Point Unit (FPU) and encryption functions
  • Up to +8 dBm TX power (down to -20 dBm in 4 dB steps)
  • NFC-A tag
• On-module additional 4MB SPI flash
• 24 mixed signal GPIO (8 x Analog, 8 x PWM), UART, I2C, SPI
• USB 2.0 full speed (12 Mbps)
• JTAG (SWD) pins
• Pins for RGB LED used for connection status
• Pins for reset and mode buttons
• On-module MFF2 Particle SIM
• Two on-module U.FL connectors for external antennas
• M.2 interface
• FCC (United States) and ISED (Canada) certified
• RoHS compliant (lead-free)

Model comparison

• EtherSIM devices generally have a larger number of carriers and more may be added in the future
• NorAm: North America (United States, Canada, and Mexico)
• Americas: North America, Central, and South America (not all countries supported)
• LTE Cat M1: Low-power cellular intended for IoT devices
• LTE Cat 1: Available in more countries and has higher data rates
• EMEAA: Europe, Middle East, Africa, and Asia (not all countries supported)
• NRND: Not recommended for new designs
• See the Carrier list for specific carrier and country compatibility
• See the Supply secure FAQ for more information
• See Lifestyle stages for more information

Device OS support

It is recommended that you use the latest version in the 4.x LTS release line with the B404X. The minimum required version is 4.0.0. You cannot use the B404X with Device OS 2.x LTS.

For information on upgrading Device OS, see Version information. For the latest version shipped from the factory, see Manufacturing firmware versions page. See also Long Term Support (LTS) releases.

Interfaces

Block diagram

Power

VCC

VCC is used to supply power to the u-blox SARA-R510S cellular module. The recommended input voltage range on this pin is between 3.6V to 4.2V DC. This can be connected directly to a 3.7V LiPo battery.

If you are not using a battery, or using a battery of a different voltage, you should use a regulator to supply 3.7V to 4.2V. While you only need 600mA for the B404X, we recommend 2A for compatibility with future SoM modules.

3V3

3V3 is used to supply power to nRF52840, logic ICs, memory, etc.. The 3V3 input voltage range is between 3V to 3.6V DC, but 3.3V is recommended. Make sure that the supply can handle a minimum of 150 mA, however we recommend a minimum of 500 mA supplied from your base board to allow for compatibility with future modules.

These limits do not include any 3.3V peripherals on your base board, so that may increase the current requirements.

Power supply requirements:

• 3.3V output
• Maximum 5% voltage drop
• 100 mV peak-to-peak ripple maximum
• 500 mA minimum output current at 3.3V recommended for future compatibility
• Maintain these values at no-load as well as maximum load

We do not recommend using a single 3.6V supply for both VCC and 3V3 as the cellular modem performance may be lower below 3.7V. Use two separate regulators for best results.

VBus

VBus is connected to the USB detect pin of nRF52840 to enables the USB interface. The recommended input voltage range is between 4.35V to 5.5V DC.

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Antenna

There are two radios on the B402 module. A BLE radio (nRF52840) and a cellular radio (u-blox). We have provided two u.FL connectors to plug in the cellular and BLE antenna. These are required if you wish to use the cellular and BLE. If you do not need BLE, you do not need to connect the BLE antenna.

Certified cellular antenna

The following antenna is included in single-unit packages that include an antenna.

General antenna parameters:

Antenna parameters in frequency ranges:

Antenna parameters in specific frequency bands:

Mechanical:

Environmental:

Alternate cellular antenna

Additionally, the following antenna is certified as an alternative antenna.

General antenna parameters:

Antenna parameters in frequency ranges:

Antenna parameters in specific frequency bands:

Mechanical:

Environmental:

Certified BLE antenna

The following antenna is optional and can be omitted if you do not wish to use BLE. It can be purchased in the Particle online store.

General antenna parameters:

Mechanical:

Environmental:

Certified NFC antenna

General antenna parameters:

Mechanical:

Environmental:

General antenna guidance

• The antenna placement needs to follow some basic rules, as any antenna is sensitive to its environment. Mount the antenna at least 10mm from metal components or surfaces, ideally 20mm for best radiation efficiency, and try to maintain a minimum of three directions free from obstructions to be able to operate effectively.
• Needs tuning with actual product enclosure and all components.
• For the BLE antenna, it is recommended to use a 2.4 GHz single-frequency antenna and not a 2.4 GHz + 5 GHz antenna, so as to avoid large gain at the frequency twice of 2.4 GHz which can cause the second harmonic radiation of 2.4 GHz to exceed standards.

Peripherals and GPIO

There are some optional B402 module specific I/O:

• u-blox USB and VBUS (for u-blox firmware upgrades)

Note: All GPIOs are only rated at 3.3VDC max.

JTAG and SWD

The B402 module has 4 pads at the bottom exposing the SWD interface of the nRF52840. This interface can be used to debug your code or reprogram your B402 bootloader, device OS, or the user firmware. We use 4 pogo-pins connecting to these pads during production for firmware flashing.

Memory map

nRF52840 flash layout overview

• Bootloader (48KB, @0xF4000)
  • User Application
  • 256KB @ 0xB4000 (Device OS 3.1 and later)
  • 128KB @ 0xD4000 (Device OS 3.0 and earlier)
• System (656KB, @0x30000)
• SoftDevice (192KB)

External SPI flash layout overview (dfu offset: 0x80000000)

• OTA (1500KB, @0x00289000)
• Reserved (420KB, @0x00220000)
• FAC (128KB, @0x00200000)
• LittleFS (2M, @0x00000000)

Pins and button definitions

Pinout diagram

Common SoM pins

RESERVED and SOM pins may vary across different SoM models. If you are designing for this specific module, or similar modules, you can use the indicated functions even if the pin is marked RESERVED. Most nRF52840-based modules will have the same pin functions on the RESERVED pins.

The nRF52840 B-SoM has some differences from the RTL8722 M-SoM. Future modules with a different MCU may have different pin functions. An effort will be made to assign all of the listed functions for ADC, PWM, SPI, etc. from the set of common SoM pin functions in future modules, but the functions on RESERVED and SOM pins will likely vary.

GPIO and port listing

ADC (analog to digital converter)

The B404X supports 8 ADC inputs.

• ADC inputs are single-ended and limited to 0 to 3.3V
• Resolution is 12 bits

On the B404X, BRN404X, and E404X, the ADC reference is the nRF52840 internal 0.6V reference, with a 1/6 gain from the input pin. This is different than other Gen 3 devices which use 3V3 as the ADC reference.

This will only affect B404X designs that have a 3V3 voltage that is not 3.3V. Previously, the ADC values would vary with the 3V3 voltage.

This reference and gain combination is a range of 0 to 3.6V for 0 - 4095. This is scaled in software so 3.3V will still be 4095, so there will be a slight loss of resolution.

UART serial

The B404X supports one UART serial interfaces.

• The UART pins are 3.3V and must not be connected directly to a RS-232C port or to a 5V TTL serial port
• Hardware flow control is optional; if not used then the RTS and CTS pins can be used as regular GPIO
• You cannot use hardware flow control and Ethernet at the same time.

SPI

The B404X supports two SPI (serial peripheral interconnect) ports.

• The SPI port is 3.3V and must not be connected directly to devices that drive MISO at 5V
• If not using a SPI port, its pins can be used as GPIO
• Any pins can be used as the SPI chip select
• Multiple devices can generally share a single SPI port
• You cannot use SPI1 and Ethernet at the same time.

I2C

The B404X supports two I2C (two-wire serial interface) ports.

• The I2C port is 3.3V and must not be connected directly a 5V I2C bus
• Maximum bus speed is 400 kHz
• External pull-up resistors are recommended for I2C as the internal pull-up is 13K.
• If not using I2C, pins D0 and D1 can be used as GPIO or analog input.
• You cannot use Wire1 and Ethernet at the same time.

PWM

The B404X supports PWM (pulse-width modulation) on the following pins:

• PWM that share the same timer (PMW2 for example) must share the same frequency but can have different duty cycles.
• Pin D7 (PWM0) share a timer with the RGB LED and you should not change its frequency but it can have a different duty cycle.

USB

The B404X supports a USB interface for programming the device and for USB serial (CDC) communications. The module itself does not contain a USB connector; you typically add a micro USB or USB C connector on your base board. It is optional but recommended.

• The Cellular Modem USB connector is optional, and can be used for firmware updates of the cellular module.

RGB LED

The B404X supports an external common anode RGB LED.

One common LED that meets the requirements is the Cree CLMVC-FKA-CL1D1L71BB7C3C3 which is inexpensive and easily procured. You need to add three current limiting resistors. With this LED, we typically use 1K ohm current limiting resistors. These are much larger than necessary. They make the LED less blinding but still provide sufficient current to light the LEDs. If you want maximum brightness you should use the calculated values - 33 ohm on red, and 66 ohm on green and blue.

A detailed explanation of different color codes of the RGB system LED can be found here.

The use of the RGB LED is optional, however it is highly recommended as troubleshooting the device without the LED is very difficult.

SETUP and RESET button

It is highly recommended that you add MODE (SETUP) and RESET buttons to your base board using momentary switches that connect to GND. These are necessary to change the operating mode of the device, for example to enter listening or DFU mode.

The MODE button does not have a hardware pull-up on it, so you must add an external pull-up (2.2K to 10K) to 3V3, or connect it to 3V3 if not using a button.

The RST pin does have an internal weak pull-up, but you may want to add external pull-up on that as well, especially if you use an off-board reset button connected by long wires.

Pin description

¹These pins are connected to the internal MFF2 SIM and should be left open.

²A0-A7 are 12-bit Analog-to-Digital (A/D) inputs (0-4095).

³SoM-specific and Reserved pins will vary depending on module. They are able to be used on the B402, but their function may be be different on future modules.

By default, the Tinker application firmware enables the use of the bq24195 PMIC and MAX17043 fuel gauge. This in turn uses I2C (D0 and D1) and pin A6 (PM_INT). If you are not using the PMIC and fuel gauge and with to use these pins for other purposes, be sure to disable system power configuration. This setting is persistent, so you may want to disable it with your manufacturing firmware only.

System.setPowerConfiguration(SystemPowerConfiguration());

If you are using Ethernet with the B-Series SoM, the following pins are used by Ethernet:

Cellular modem USB pins

The cellular modem USB pins are optional on custom base boards. These pins are used for low-level diagnostics and reprogramming the cellular modem firmware.

Note, however, the Particle has never done a cellular modem firmware upgrade in the field because doing so generally requires recertification, and is there is a high likelihood that the upgrade will fail, rendering the modem unusable.

Cellular modem could be reprogrammed by removing the SoM from your board and putting it in the M.2 SoM breakout board, which has the cellular modem USB connector.

Complete module pin details

Show pin details

LED status

System RGB LED

Unlike the Boron, the B402 module does not have an on-module RGB system status LED. We have provided its individual control pins for you to connect an LED of your liking. This will allow greater flexibility in the end design of your products.

A detailed explanation of different color codes of the RGB system LED can be found here.

PMIC Notes

When using the B-Series SoM with a bq24195 PMIC, note the following:

By default, the bq24195 sets the input current limit, which affects powering by VIN and VUSB, to 100 mA. This affects the VSYS output of the PMIC, which powers both the cellular modem and 3V3 supply, and is not enough to power the B-Series SoM in normal operation.

If your device has the default firmware (Tinker), it will attempt to connect to the cloud, brown out due to insufficient current, then the device will reset. This may result in what appears to be the status LED blinking white, but is actually rolling reboot caused by brownout.

A factory new B-Series SoM does not enable the PMIC setup. To enable the use of the bq21415, you must enable the system power feature PMIC_DETECTION in your code. This defaults to off because the B-Series SoM can be used without a PMIC, or with a different PMIC, and also requires I2C on D0/D1, and some base boards may use those pins as GPIO.

Because the input current limit does not affect the battery input (Li+), for troubleshooting purposes it can be helpful to attach a battery to help rule out input current limit issues. It's also possible to supply 3.7V via a bench power supply to the battery input, instead of VIN.

The input current limit can result in a situation where you can't bring up a B-Series SoM because it browns out continuously, but also cannot flash code to it to stop if from browning out. There are two general solutions:

• Attach a battery or supply by Li+ when bringing up a board.
• Use SWD/JTAG and reset halt the MCU. This will prevent it from connecting to the cloud, so you can flash Device OS and firmware to it by SWD.

The input current limit is actually controlled by three factors:

• The power source max current setting in the PMIC. The default is 900 mA. It can be set to 100, 150, 500, 900, 1200, 1500, 2000, or 3000 mA.
• It is also limited by the hardware ILIM resistor. On Particle devices with a built-in PMIC, this is set to 1590 mA, but if you are implementing your own PMIC hardware, you can adjust this higher.
• When connected by USB, it will use DPDM, current negotiation via the USB DP (D+) and DM (D-) lines.

Note that some 2A tablet chargers and multi-port USB power supplies supply 2A but do not implement DPDM; these will be treated as if VIN was used, and you must set the power source current, otherwise the input current will be limited to 900 mA, which is not enough to power a 2G/3G cellular modem without an attached battery.

Technical specifications

Absolute maximum ratings ^[1]

Supply voltages

^[1] Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

Recommended operating conditions

Notes:

¹ Normal operating temperature range (fully functional and meet 3GPP specifications).

² Extended operating temperature range (RF performance may be affected outside normal operating range, though module is fully functional)

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Power consumption

Values are from B404/B402. Actual operating current with cellular using the R510 modem may vary but should be similar.

¹The min, and particularly peak, values may consist of very short transients. The typical (typ) values are the best indicator of overall power consumption over time. The peak values indicate the absolute minimum capacity of the power supply necessary, not overall consumption.

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Radio specifications

The B-Series SoM has two radio modules.

Nordic Semiconductor nRF52840 for BLE

Nordic Semiconductor nRF52840 for NFC tag

u-blox SARA-R510S-01B

• LTE Cat M1 for United States, Canada, and Mexico.
• FCC Certification in the United States only tests bands in use in the United States.
• Bands not listed as certified are disabled in the Device OS operating system and cannot be enabled from user firmware.
• Particle LTE Cat M1 devices are not certified for use in Europe or other countries that follow EU certification requirements.
• ¹3GPP Release 14 LTE Cat M1: Coverage Enhancement Mode B, Uplink TBS of 2984b

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I/O characteristics

These specifications are based on the nRF52840 datasheet.

• Rise and fall times based on simulations

• GPIO default to standard drive (2mA) but can be reconfigured to high drive (9mA) in Device OS 2.0.0 and later using the pinSetDriveStrength() function.

Mechanical specifications

Dimensions and weight

3D models

3D models of the B-Series SoM module are available in the hardware-libraries Github in formats including step, iges, stl, and f3d.

The 3D models are the same for the B404X and B402 as the cellular modem module is the same size.

Mechanical drawing

Dimensions are in millimeters.

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Mating connector and land pattern

The mating connector is a an M.2 (NGFF) type 4. Note that there are several different key configurations for the M.2, and type 4 is different than is commonly used on SSDs.

One compatible connector is the TE 2199230-4. It is widely available including at suppliers such as DigiKey.

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Screw assembly

The M.2 SoM requires a screw to hold the SoM in place because the M.2 connector does not have integrated locks and the SoM will pop up if not attached to the base board. The screw also provides better vibration resistance than locking clips.

• This is one style of standoff.

• An alternative design uses a JAE SM3ZS067U410-NUT1-R1200 standoff. It's reflow soldered to your base board and has a threaded hole for a M2*3 screw to hold down the SoM. This may be easier to obtain.
• The screw should be connected to the ground plane on your base board.

Design considerations

We strongly recommend against placing components under the SOM board because there is not enough height.

Product handling

ESD precautions

The B series contains highly sensitive electronic circuitry and is an Electrostatic Sensitive Device (ESD). Handling an B series without proper ESD protection may destroy or damage it permanently. Proper ESD handling and packaging procedures must be applied throughout the processing, handling and operation of any application that incorporates the B series module. ESD precautions should be implemented on the application board where the B series is mounted. Failure to observe these precautions can result in severe damage to the B series!

Connectors

The U.FL antenna connector is not designed to be constantly plugged and unplugged. The antenna pin is static sensitive and you can destroy the radio with improper handling. A tiny dab of glue (epoxy, rubber cement, liquid tape or hot glue) on the connector can be used securely hold the plug in place.

The M.2 edge connector is static sensitive and should be handled carefully. The M.2 connector is not designed for repeated removal and insertion of the module.

Schematics

Microcontroller

u-blox cellular modem

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M.2 connector

Note: An earlier version of this document had reversed the labels D2 and D3 in the diagram located here. The correct assignments are pictured above and are as follows:

SIM and Flash

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Assembly

Conformal coatings

B-Series SoM modules should not use a conformal coating to protect the module from water. Some components on the SoM cannot be coated and would need to be masked off during coating. This will make the coating process difficult to implement and test.

Furthermore, you cannot safely protect the the connection between the M.2 SoM and the M.2 NGFF connector by using a coating. Using an enclosure that protects both your base board and the B-Series SoM as a single waterproof assembly is recommended instead.

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Default settings

The B series comes pre-programmed with a bootloader and a user application called Tinker. This application works with an iOS and Android app also named Tinker that allows you to very easily toggle digital pins, take analog and digital readings and drive variable PWM outputs.

The bootloader allows you to easily update the user application via several different methods, USB, OTA, Serial Y-Modem, and also internally via the Factory Reset procedure. All of these methods have multiple tools associated with them as well.

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FCC ISED CE warnings and end product labeling requirements

Federal Communication Commission Interference Statement This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

FCC Caution: Any changes or modifications not expressly approved by the party responsible for compliance could void the user's authority to operate this equipment. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:

1. This device may not cause harmful interference, and
2. This device must accept any interference received, including interference that may cause undesired operation.

FCC Radiation Exposure Statement: This equipment complies with FCC radiation exposure limits set forth for an uncontrolled environment. This transmitter module must not be co-located or operating in conjunction with any other antenna or transmitter. This End equipment should be installed and operated with a minimum distance of 20 centimeters between the radiator and your body.

IMPORTANT NOTE: In the event that these conditions can not be met (for example certain laptop configurations or co-location with another transmitter), then the FCC authorization is no longer considered valid and the FCC ID can not be used on the final product. In these circumstances, the OEM integrator will be responsible for re-evaluating the end product (including the transmitter) and obtaining a separate FCC authorization.

End Product Labeling The final end product must be labeled in a visible area with the following:

• Contains FCC ID: 2AEMI-B404X

Manual Information to the End User The OEM integrator has to be aware not to provide information to the end user regarding how to install or remove this RF module in the user’s manual of the end product which integrates this module.

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Canada Statement This device complies with Industry Canada’s licence-exempt RSSs. Operation is subject to the following two conditions:

1. This device may not cause interference; and
2. This device must accept any interference, including interference that may cause undesired operation of the device.

Le présent appareil est conforme aux CNR d’Industrie Canada applicables aux appareils radio exempts de licence.

L’exploitation est autorisée aux deux conditions suivantes:

1. l’appareil ne doit pas produire de brouillage;
2. l’utilisateur de l’appareil doit accepter tout brouillage radioélectrique subi, même si le brouillage est susceptible d’en compromettre le fonctionnement.

Caution Exposure: This device meets the exemption from the routine evaluation limits in section 2.5 of RSS102 and users can obtain Canadian information on RF exposure and compliance. Le dispositif répond à l'exemption des limites d'évaluation de routine dans la section 2.5 de RSS102 et les utilisateurs peuvent obtenir des renseignements canadiens sur l'exposition aux RF et le respect.

The final end product must be labelled in a visible area with the following: The Industry Canada certification label of a module shall be clearly visible at all times when installed in the host device, otherwise the host device must be labelled to display the Industry Canada certification number of the module, preceded by the words “Contains transmitter module”, or the word “Contains”, or similar wording expressing the same meaning, as follows:

• Contains transmitter module ISED: 20127-B404X

This End equipment should be installed and operated with a minimum distance of 20 centimeters between the radiator and your body. Cet équipement devrait être installé et actionné avec une distance minimum de 20 centimètres entre le radiateur et votre corps.

The end user manual shall include all required regulatory information/warning as shown in this manual.

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Certification documents

Bluetooth - B404X B-Series SoM

• Bluetooth

CE (Europe) - B404X B-Series SoM

The B404X are not certified for use in Europe at this time. The B524 (LTE Cat M1 with 2G/3G fallback) is recommended instead.

FCC (United States) - B404X B-Series SoM

• FCC ID: 2AEMI-B404X
• Grant of equipment authorization (DTS)
• Grant of equipment authorization (PCB)
• Attestation 15 Subpart B, Class B (sDoC)
• RF Exposure Report FCC Part 2, Section 2.1091
• Test report FCC Part 15 Subpart C, Section 15.247
• Test report FCC Part 22, Part 24, Part 27

ISED (Canada) - B404X B-Series SoM

• ISED: 20127-B404X
• Certificate of Conformity
• Test Report RSS-247 Issue 2, RSS-Gen Issue 5
• Test Report ICES-003 Issue 7:2020 Class B
• Test Report RS-132 Issue 3, RSS-133 Issue 6, RSS-139 Issue 4

Country compatibility

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Ordering information

Revision history