Short-Range Wireless Radios Offer An Embarrassment Of Riches
Fig 1. CEL’s ZICM0900P2 MeshConnect Sub-1G module operates in the 902- to 928-MHz ISM band and provides a link budget up to –140 dBm for long-range operation. It uses a Silicon Labs Si100x wireless SoC IC with on-board 8051 MCU.
Fig 2. The Semtech SX1240 and SX1242 transmitters operate in the sub-1-GHz ISM band and provide a simple, low-cost way to perform RKE or other remote control functions without the need for an external microcontroller.
It seems like all products are going wireless. Name a recent electronic product that doesn’t have a wireless element. That means more and more engineers are adding wireless to current designs. That used to be a huge effort due to the lack of suitable chips and support components like antennas, not to mention the overall lack of wireless knowledge amongst most electronic engineers (EEs).
Today there are multiple wireless technologies for every application, as well as a large number of chips and modules to choose from. If you’re designing a new wireless product for industrial monitoring and control, smart grid metering, home automation, lighting, irrigation, security, vending machines, games, or data loggers, you may be interested in some of these recent announcements.
Analog Devices
Analog Devices has a new chip to add to its extensive portfolio of RF transceivers and other RF ICs. The ADF7241 supports the IEEE 802.15.4 protocol in the 2.4-GHz band with a data rate of 250 kbits/s. The emphasis is on flexibility, ease of use, and low power consumption. The transceiver uses only 19 mA when receiving and 21.5 mA when transmitting, making it ideal for battery-powered sensor networks, wireless metering, or a consumer application.
The receiver is a zero-IF type with a sensitivity of -95 dBm. The transmitter is based on an internally modulated voltage controlled oscillator (VCO). Output power can be varied in 2-dB steps from –20 dBm to +4.8 dBm. Antenna diversity is supported.
The ADF7241 also has a built-in custom 8-bit processor used for radio control and packet management. Voltage regulators are integrated on chip allowing operation from any dc source from 1.8 to 3.6 V. The chip complies with a number of key industry standards including EN300 440 Class 2, EN300 328, FCC CFR47 Part 15, and ARIB STD-T66. The chip is packaged in a 32-lead lead frame chip scale package (LFCSP).
The product is available now and priced at $1.98 in 1000-unit quantities. An evaluation board is available. The ADIsimSRD design aid enables real-time simulation and optimization of typical wireless systems.
Also, the ADF7023-J transceiver targets short range wireless applications in Japan and addresses the Association of Radio Industries and Businesses (ARIB) STD-T96 standard protocol. It operates over the 902- to 958-MHz range with data rates to 300 kbits/s using two-frequency shift-keying/ Gaussian frequency shift keying (2FSK/GFSK). A programmable 8-bit processor is also embedded. Pricing is $2.62 in 1000-unit quantities.
California Eastern Laboratories
CEL’s MeshConnect Sub-G modules target applications in the high-frequency industrial, scientific, and medical (ISM) bands of 868 MHz (Europe) and 902 to 928 MHz (Americas). While the 2.4-GHz band seems to get all the attention these days, the sub-1-GHz band has major advantages. First, it is not as congested as the 2.4-GHz band with its Wi-Fi, Bluetooth, ZigBee/802.15.4, cordless phones, and other stuff. Second, the sub-1-GHz band gives longer range, better obstacle penetration, and better non-line-of-sight performance, which are major benefits in some applications.
Ready to use, the ZICM0868P0 fits Europe and the ZICM0900P2 is designed for the Americas (see figure 1). Just add an antenna and dc power and program your application. Such modules offer the advantage of minimal design time, cost, and knowledge, as well as a shorter time to market and no Federal Communications Commission (FCC) or CE certification process.
The radio features a receive sensitivity in the –99- to –121-dBm range, transmit power of +13 dBm for the 868-MHz module and +20 dBm for the 902-928 MHz module. Total link budgets are –111 dBm and –140 dBm, respectively. The data rate can be anything from 123 bits/s to 150 kbits/s. The modulation is frequency-hopping spread-spectrum with FSK. The CEL modules use a Silicon Labs Si100x single-chip RF system-on-a-chip (SoC) plus MCU.
The MCU is an 8051 with 64 kbytes of embedded flash and 4 kbytes of RAM. A 10-bit analog-to-digital converter (ADC) and various serial I/O options are included. Software comes from CEL’s application programming interface (API), which supports mesh, star, and point-to-point (P2P) topologies as well as frequency hopping and listen before talk features. Software options include SNAP, which supports mesh networks, M-Bus (Europe) and Silicon Labs EZMac. Sample modules are available now with full production available in June. Pricing is below $19 in 1000-unit quantities.
Nordic Semiconductor
Nordic Semiconductor has an interesting line of ISM band and Bluetooth wireless products for short-range applications. The µBlue nRF8001 implements the Bluetooth SIG ultra low power (ULP) wireless standard 4.0. With all the features of standard Bluetooth, it uses frequency hopping spread spectrum in the 2.4-GHz ISM band and has a data rate of 1 Mbit/s with a range up to 15 meters. The nRF8001 has a peak current of 12.5 mA and connected mode average current of 12 µA based on one-second connection intervals. This low-energy device can operate for years with a basic coin-cell supply.
While widely known for its use in hands-free operation of cell phones, Bluetooth can be used in many other wireless applications. The new ULP 4.0 version opens up the applications to mobile devices or sensors worn on or carried by the end user’s body. This includes cell phone peripherals, proximity tags, watches, sports, fitness, and health sensors. Other applications are human interface devices like keyboards, mice, motion controllers, and consumer remote controls, as well as special industrial automation devices.
The nRF8001 integrates a 32-kHz RC clock oscillator, an optional 16-MHz oscillator for use with an external crystal, a linear voltage regulator that provides a supply voltage of 1.9 to 3.6 V, and an optional dc-dc converter for use with coin cells. The package is a 5- by 5-mm, 32-pin quad flat no-lead (QFN). Samples and a development kit are available now.
Semtech
Semtech “power-and-go” platform aims to simplify the addition of wireless to consumer and commercial products. It is a cost-effective way to add one-way remote keyless entry (RKE) and remote control to almost any product. Target applications include auto key fob, garage door openers, home and building automation, patient monitoring, and active radio frequency identification (RFID).
The Semtech SX1240 can operate in the 418-, 434-, and 868-MHz ISM bands. It uses either FSK or on-off keying (OOK) at a rate to 100 kbits/s. It can be preconfigured so it can operate without an external microcontroller, although a separate MCU can be used if needed. Power consumption at +10-dBm output power is 16.5 mA or only 9 mA at 0 -Bm output. The output will accept a wide range of simple antenna designs without complex tuning.
The SX1242 is another transmitter that works on the 345-MHz ISM band. Using OOK modulation it can achieve a data rate of up to 10 kbits/s. Current consumption is 22 mA with a +12-dBm output. No external MCU is needed. The SX1240 and SX1242 come in an eight-pin small outline IC (SOIC) package (see figure 2).
If a receiver is needed, the choice is the SX1239. It operates on all of the relevant ISM frequencies including 345, 418, 434, 868, and 914 MHz. It works with the FSK, GFSK, MSK, GMSK, and OOK modulation modes. Receive sensitivity varies with frequency but is in the –120-dBm range. When used with the SX1240, the link budget can be a great as –130 dBm, giving very long range performance. The SX1239 receiver comes in a 24-pin QFN package.
All of these devices are available now. Price for the SX1240/1242 is $0.58 in lots of 2500 units. The SX1239 costs $1.37 in 3000-piece quantities. Evaluation kits are available.
Texas Instruments
The Texas Instruments CC112x series, a line of narrowband ISM band transceivers, can operate in the usual 433-, 868-, 915-, and 950-MHz bands as well as the new 169-MHz band (new in Europe). The CC112x family offers a receive sensitivity of –123 dBm and a maximum +14-dBm transmit output giving an amazing –137-dB link budget. This provides a line of sight range of over 10 km. Adjacent channel rejection using 12.5-kHz bandwidth is greater than 60 dB. Blocking at 2 MHz is greater than 84 dB.
The CC112x’s low-power 3-mA receive “sniff mode” allows the radio to listen for relevant RF packets while consuming only minimal power. A very low transmit phase noise figure lets designers use an external power amplifier without extra filtering to extend the range while meeting regulatory compliance. The package is a 5- by 5-mm, 32-pin QFN.
The CC112x devices will be available in samples in the second quarter of 2011 with full production in the third quarter. Development kits and tools are available.
ZMDI
ZMDI has a new wireless radio that fits the needs of those who need a very secure link or network. The ZWIR4512 module implements the Internet Engineering Task Force (IETF) 6LoWPAN protocol that lets you send IPv6 packets over an IEEE 802.15.4 wireless link. The radio uses the standard 2.4-GHz ISM band with either BPSK or O-QPSK at rates of 20, 40, 100 or 250 kbits/s depending on U.S. or European applications. Power output is up to +10 dBm.
The ZWIR4512 also has a 32-bit ARM Cortex M3 microcontroller on board with 192 kbytes of flash and up to 32 kbytes of RAM. Multiple I/O interfaces are available as well as a pulse-width modulator (PWM), an ADC, and a digital-to-analog converter (DAC).
This module is designed for mesh sensor networks in the industrial and building automation, health monitoring, and smart metering applications areas. It provides simplicity in network management, mesh routing with self-healing capability, data encryption and authentication, and multiple interfaces. It uses the standard IPSec and IKEv2 security libraries.
The ZWIR4512 module has dimensions of 28 by 16.5 by 3.5 mm and operates from 2.0 to 3.6 volts. Development kits are available.
Analog Devices
www.analog.com/ADF7241
California Eastern Laboratories
www.cel.com
Nordic Semiconductor ASA
www.nordicsemi.com
Semtech
www.semtech.com
Texas Instruments
www.ti.com/lprf
ZMDI
www.zmdi.com
