Nordic Semiconductor's Tape And Reeled 2.4 GHz Wireless Modules ...

Tag : Semiconductor

Oslo, Norway - Ultra low power (ULP) RF specialist NordicSemiconductor ASA recently announced its official design partner,Irvine, CA-based RF Digital, has released a fully FCC andCE-compliant 2.4GHz ULP wireless module that is supplied tape andreeled at a US$8 unit cost for volume orders.
The tape and reeled format enables customers (or theirsubcontractors) to place the module on the PCB using automatedplacement equipment. Automated assembly, together with the lowprice and the fact that customers require no further certificationprior to releasing products to market, makes the module acompelling solution for production runs from 10 to 100,000 units.
The RFD21733 measures just 15 by 15 by 3mm and is powered byNordic's brand new, class leading nRF24LE1 2.4GHz ULP transceiver.The nRF24LE1 is a high performance wireless device integratingradio, microcontroller and flash memory (see "About the nRF24LE1"below).
The RFD21733 is supplied with RF Digital's proven Frequency HoppingSpread Spectrum (FHSS) firmware, or alternatively with nopre-loaded firmware (module part number RFD21731). Both modulesfeature a built in chip antenna which is matched, tuned andradiation pattern optimized. A 32kHz crystal required for precisiontiming when operating in a low duty cycle ULP mode is alsointegrated into the RFD21732 module which has no pre-loadedfirmware. Full access to the wireless module is provided to threedigital in/out lines, program line, reset line, power (+V) andground (GND) connections.
The RFD21733 is particularly suitable for designers that may be newto wireless as everything on the RF side of the device is in place,tested and proven (see "Why use a module?" below). In thisconfiguration, the module runs at 9600 baud and features N, 8, 1serial interface firmware allowing it to be connected directly toan RS232 level shifter. In addition, the module features a built inswitch follower mode. Pressing a button on the transmitter willcause the corresponding button on the receiver to activate; thisbutton could, for example, be connected to an LED to facilitaterange testing or used in end-product applications such as keylessentry door openers or long range RFID applications.
For more experienced designers who want to take advantage of themodules' high bandwidth (up to 2Mbps raw data rate), ultra lowpower consumption (down to microamps average current) and abilityto communicate with up to five other devices in apoint-to-multipoint topology, the modules can be programmed usingNordic's nRF24LE1 Development and Evaluation Kit. Because thetransceiver used in the modules is an integrated device, there isno requirement for a separate development and evaluation kit toaccess the microcontroller.
RF Digital is also releasing an adaptor board to interface themodules to the Nordic nRF24LE1 Development and Evaluation Kit, anda miniature evaluation board complete with module, three buttonsand three LEDs (enabling range testing) powered by a CR2032 3V coincell-type battery. (This battery is a typical choice for ULPwireless applications.) Since this miniature evaluation boardincludes the RFD21733 compliance tested module, it no longerrequires any further compliance testing and can even be used as thebasis of a marketable product. The miniature evaluation board alsohas 0.100 spacing SIP header which allows it to easily plug intousers' development boards.
Requiring only 15 by 15mm2 board area, the modules are suitable forall but the most space-constrained applications. And at a price ofas low as US$8 (in volume) they offer a cost effective alternativeto a discrete component RF design for production runs numbering upto hundreds of thousands of pieces per year. Should a manufacturerthen want to move to a discrete component design later in theproduct's life, the module represents an ideal reference design.
"Our philosophy is to make life as simple as possible for engineerswanting to implement a wireless link," explains RF DigitalPresident Armen Kazanchian. "With these new modules an engineer canhave a link up and running within minutes. And there is no need forany compliance testing as the module already conforms.
"Moreover, these modules are based on the leading 2.4GHztransceiver in its class, so the performance is the best money canbuy at this price point. In fact, these modules significantlyoutperform competitive products costing three or four times asmuch. And at only 15 by 15mm the modules do not compromise compactdesigns," says Kazanchian.
"The cost difference between the fully compliant, tested and provenmodule complete with protocol code and the discrete componentsrequired to produce an equivalent design is only around US$3 (involume) thanks to the advances in technology and manufacturingprocesses. With compliance testing alone costing thousands ofdollars, the module makes great economic sense for all but thelargest production runs," Kazanchian concludes.
"RF Digital has excelled in the provision of wireless modules forcompanies lacking RF engineering experience but needing a provenwireless solution and fast-time-to-market, and this latest product,based on our nRF24LE1, is no exception," says Geir Langeland,Director of Sales & Marketing, Nordic Semiconductor. "And becausethe functionality of the transceiver used in the module can bemodified by employing Nordic's Development and Evaluation Kit, moreexperienced designers can port their own code to furtherdifferentiate their products from the competition."
Why use a wireless module?
An RF module is a good solution for designers looking to addwireless connectivity to a product without committing to an arduousdesign cycle. By using a module, designers without specialist RFknowledge can build an Ultra Low Power (ULP) ISM-band wireless linkinto a product or application within hours.
Because all the RF development work has been done, a module onlyrequires a digital In/Out, power (+V) and ground (GND) connection.The module is impedance matched, includes antenna and is tested forrange and robustness of communication. In many cases, the module isalso tested to the US' FCC and Europe's ETSI regulations. Moreover,by using a module, engineers don't need to get involved with the RFside when developing, for example, a proof of concept.
A module is designed to work in almost any operating environment orproduct design with the exception of a sealed metal enclosure(which is opaque to RF).
There is one downside: a module takes up more board real estate andhave a taller profile than employing the equivalent transceiver(and supporting peripheral components). But at only 15 by 15 by 3mma module is suitable for all but the most space constraineddesigns. But even if the module is still too big, and the finaldesign does require discrete components, a module is still worthconsidering for prototyping because of the time saved duringdevelopment.
A module also costs slightly more than the equivalent discretecomponents. However, to make a like-for-like comparison, thesavings made in expensive design hours must be factored in. Andthis is without accounting for the several thousands dollars savedbecause the module already has FCC compliance approval.
By using an RF module, it's possible to test RF performance at theprototype stage rather than waiting for a production PCB. And whenthe production PCB arrives, there is rarely a need for a layoutrevision. With a module, the designer can be confident that allunknown RF variables are stable and independent of the targetapplication. In addition, the RF section of their product ismodular and therefore simple to debug. Contrast this with a designthat uses discrete RF components: even the most experienced RFengineer doesn't know if such a layout will pass compliance testinguntil it has gone through the lab. And more often than not, the PCBand layout will require a second and third revision to passcompliance testing.
In addition, the designer faces initial RF engineering costs, theexpense of RF test equipment to debug in engineering andproduction, and further RF engineering costs to address radiationpatterns, range limitations and interactions between digital and RFparts of the design (which only become apparent once a complete RFlayout is tested). While the competition is designing, prototypingand waiting on compliance test results, an RF module-based productcould already be selling in the marketplace.
If volumes then increase and the additional cost of the modulebecomes significant, it can be replaced with the less expensivediscrete components. Because RF Digital's modules are based onNordic Semiconductors reference designs, the designer can simplyadopt the relevant reference design in the space vacated by themodule.
SOURCE: Nordic Semiconductor ASA