Analog Devices' Wireless
WSN solutions made easy for Internet of Things (IoT) applications
Internet of Things (IoT) connects places such as buildings and spaces with sensors, radios, and electronic computing (microcontrollers) with networks, software, the cloud, and you. The challenge is to get a diversity of products to interoperate with each other to enhance a network with real-world applications. ADI has Wireless Sensor Network (WSN) solutions to help everyone, from the most novice Maker to the seasoned Engineer. The ideal WSN has autonomous sensors to monitor physical or environmental conditions, such as temperature, sound, vibration, pressure, humidity, motion, or pollutants. Sensors collectively pass their data through wireless (transceivers) modules to a network to a main control point. WSN can contain just a few nodes to thousands of nodes. Today's nodes need to be self-contained with many having a connected microcontroller (MCU), transceiver and antenna. The need for extremely low power consumption is a must since nodes are generally battery powered. Today, many nodes have energy harvesting capabilities to extend battery life.
With any WSN one needs to start with in the physical space and what needs to be measured. A variety of sensors, analog front ends (AFEs) and amplifiers can be used. ADI has two digital temperature sensors; the ADT75 has 12-bit power and the ADT7420 has 16-bit power and has an I2C interface. The AD7171 is a 1-channel capacitance converter whereas the AD7745, also a 1-channel converter, is 24-bit and was designed for proximity sensing. For a 3-axis MEMS accelerator the ADXL362 has a digital output.
The AD7798/AD7799 are low power, low noise, AFEs for high precision measurement applications. The AD7798/AD7799 contain 16-/24-bit Sigma-Delta (Σ-Δ) Analog to Digital Converters (ADCs) with three differential analog inputs. The AD7792 is a 3-channel 16-bit Sigma Delta ADC with on-chip in amplifier (amp) and reference. For 20-bit power the AD7781 is also a (Σ-Δ) ADC. Lastly, the ADA4528 is a 5 V ultra-low noise rail-to-rail (RRIO) dual-operational (OP) amp.
Transferring data up stream and commands downstream requires a form of communication that is either wired or wireless. Most IoT solutions are wireless solutions utilizing several frequency bands; these frequencies are known as Industrial Scientific and Medical (ISM) bands. It is important to use the match transceiver for the frequencies that you will be using. The ADF7030 is a high performance, low power, 169MHz ISM band, radio transceiver. Both the ADuCRF101 and ADF7020 are for frequency ranges of 433-464 MHz and 862-928 MHz. The ADuCRF101 has an additional ARM® Cortex®-M3 MCU core. The narrowband ISM transceiver ADF7021 has frequencies ranges of 80-650MHz and 862-940MHz. For IEEE 802.15.4 (Wi-Fi) Zero-IF 2.4 GHz transceivers, there is ADF7241/ADF7242. ADI has variety of microcontrollers for WSN. The three most important use ARM Cortex-M3 technology. The ADuCRF101 is both a transceiver and MCU. The ADuCM362/ADuCM363 are both low power, precision MCUs with Sigma-Delta ADCs. The ADuCM362 has dual ADCs whereas the ADuCM363 has a single ADC.
Extremely-low power consumption for IoT devices is a must. ADI has a series of linear dropout (LDO) regulators for this very purpose. The ADP125 is a 5.5V, 500mA CMOS regulator and the ADP160 is a 150 mA, CMOS regulator. The ADP3330 has anyCAP® technology and can provide 200mA of current. The ADP5054 is a Quad (4) Buck or step of regulator and power solution. For energy harvesting the AD7781 is a complete low power front-end solution with its 20-bit Sigma-Delta (Σ-Δ) ADC, an on-chip, low noise programmable gain amplifier (PGA), and an on-chip oscillator.
The building block of any circuit is the amplifier (AMP). The AD8236 is a 40 µA Micropower Instrumentation Amp and the ADA4692 is a quad output 3.6 MHz, Low Noise, Rail-to-Rail Output, Operational (OP) Amp. ADI has several multiplexers (MUX) ideal for IoT applications. The MUX will allow analog or digital input signals combined and transmitted on a single line. The ADG439 is a High Performance, 4-Channel, Fault-Protected Analog MUX. For 8-Channel/4-Channel Fault-Protected MUX the ADG509 is available. There are three MUXs with ADI's iCMOS® technology. The ADG1208 is an 8-Channel, ±15 V/+12 V MUX, the ADG1209 is a 4-Channel, ±15 V/+12 V and the AD1408 is a 4 Ω Ron, 8-Channel ±15 V /12 V /±5 V MUX.
System Block Diagram