Getting Started With nRF7002 & nRF52

It’s getting harder to find new electronics that don’t include WiFi and/or Bluetooth as standard features, and many of today’s components provide very easy paths to adding these features to a new product. The nRF7002 is one such device that works well with Bluetooth-enabled microcontrollers and offers a convenient way to add WiFi to a Bluetooth-based system. 

In this article, we’ll show you how the nRF7002 easily pairs with standard or Bluetooth-enabled microcontrollers, and where you can access resources for creating your own PCB with the nRF7002. 

How Does the nRF7002 Work? 

The nRF7002 is a WiFi transceiver chip that is complementary to a standard microcontroller. On the nRF7002 product page and in the datasheet, the component is primarily described as being a complementary part that adds WiFi capabilities to the nRF52/nRF53 microcontroller family. These microcontrollers have a 2.4 GHz interface that supports Bluetooth; adding the nRF7002 to this system gives WiFi capabilities. 

 The nRF7002 is part of a family of nRF700x components, all of which provide different generations of WiFi in a system. Although the Nordic documentation states these chips are meant for use with nRF52 or nRF53, the nRF700x parts work with standard microcontrollers and Bluetooth-enabled microcontrollers from any vendor. A brief comparison is shown below. 

All three of these components can be used to build a relatively simple architecture when used with a Bluetooth-enabled microcontroller, such as the nRF52 or nRF53. Among these three options, the nRF7002 is the most advanced by virtue of its packaging options and wireless capabilities. 

The nRF7002 comes in a variant with wafer-level chip-scale packaging (WLCSP), which is a type of high density BGA package with small ball pitch. One should note that the nRF52 is also available in WLCSP, and together the nRF7002 + nRF52 architecture is physically much smaller than many other off-the-shelf microcontroller modules. This is one of the big advantages of using nRF7002 in WLCSP as an add-on to nRF52 in WLCSP, and it is an area where many other Bluetooth-enabled microcontrollers cannot compete. 

Whether you decide to use the WLCSP or the QFN packaging, the system architectures that can be constructed with the nRF7002 will be the same. Both packages will interface with a microcontroller over SPI/QSPI and both with require additional RF components for the wireless interfaces to operate. 

System Architecture With a Bluetooth Microcontroller 

Because WiFi and Bluetooth can operate in different frequency bands and with different data formats, these interfaces may require different antennas. Supporting RF components, such as an antenna switch or diplexer, may also be required. Some examples from the nRF7002 datasheet are shown below. 

For example, take a look at the generic MCU-based architecture shown below. In the simplest architecture, each wireless interface (2.4 GHz WiFi, 5 GHz WiFi, and Bluetooth) would have its own separate antenna. One way to reduce the number of antennas is to use a diplexer with a dual-band antenna. The diplexer will passively separate the 2.4 GHz and 5 GHz WiFi signals received by the dual-band antenna during operation. 

Dual-band antenna architecture with generic host MCU.

Next consider the system architecture involving an nRF53 Bluetooth-capable microcontroller. Because Bluetooth also operates near 2.4 GHz, the diplexer will still be used to route 2.4 GHz and 5 GHz to the WiFi antenna, but an additional antenna switch is required to switch between 2.4 GHz outputs. The antenna switch is actively toggled in order to select between the Bluetooth output and the 2.4 GHz WiFi output. 

Dual-band antenna architecture with nRF53 host MCU.

In these system architecture examples, the antenna must be a dual-band antenna, which some designers may find challenging to design and simulate. However, it is possible to use two separate antennas, one for the 5 GHz WiFi output and another for the 2.4 GHz outputs. These antennas could also be printed antennas on the PCB, or antenna modules that plug into an SMA or U.FL connector. 

Fastest Way to Start Using nRF7002 

If you’re going to design a custom PCB with the nRF7002, you’ll need to start with verified schematics directly from the manufacturer. Normally, designers would need to combine portions of the reference designs for the nRF7002 and the microcontroller. In the case of a Bluetooth + WiFi system, a diplexer or antenna switch will also be needed to select between different wireless protocols. 

The best way to get started on this task is to create your system design in CELUS. Inside the CELUS Design Platform, users can build a system that will automatically combine the nRF7002 with a Bluetooth-capable microcontroller like the nRF52, as well as other sensors or components for your new product. 

CELUS currently features an nRF7002 Arduino Hat featured project that can be modified to integrate with other components on the CELUS platform. The block diagram is shown below; the nRF7002 schematics are currently lumped into the “Wireless Communication” block. 

nRF7002 block diagram on the CELUS Design Platform

To get started, make a copy of the project and start modifying the block diagram to suit your needs. Once you’ve completed your design, you can export the completed schematics to popular ECAD file formats and start designing your custom PCB. 

Learn more about using the CELUS Design Platform in the following video. 

With the CELUS Design Platform, designers can speed up their development efforts with components from their favorite manufacturers. By defining components and their associated circuitry as CUBOs, CELUS helps reduce risk for designers and allows generated designs to be immediately used in industry-standard ECAD tools. This shifts a designer’s focus from circuit design to system design and allows a designer to more efficiently integrate diverse features into a new product. 

To get access to these nRF7002 design resources, sign up for CELUS today.