Developers can use these devices to quickly implement
sensing systems with few additional components. For simple
applications, developers need to do little more than connect a
sensor transducer to the AFE's analog input, add decoupling
capacitors, and connect a microcontroller (MCU) to the device's
serial output. The bidirectional analog ports further simplify their
use with resistive sensors such as strain gauges or RTDs that
typically required in process-control applications. Developers can
use an AD7124-4 analog pin to provide the excitation current
needed to drive these sensors
(Figure 1).
For custom signal chains, developers can augment their
designs with low-power devices needed for specialized signal
conditioning or conversion. For precision measurements, Analog
Devices' ADA4051-1, ADA4051-2, and LTC2063 consume only
microamps of current, offering zero-drift op amps with very low
offset voltage, drift, and input bias current. Developers can pair
these op amps with conversion devices such as the AD5592R
or AD5593R, which integrate a 12-bit ADC and 12-bit Digital-to-
Analog Converter (DAC) accessible through an SPI (AD5592R)
or I2C (AD5593R) interface.
Increasingly, however, developers can find AFEs developed to
meet requirements in specific application areas. For example,
Analog Devices' AD823x integrate a complete signal chain
for bio potential measurements including electrocardiograms
(ECGs) and electromyograms (EMGs) used in wearable
heartrate monitors, gaming peripherals, and other personal
products. Even with their extensive functionality, the devices
allow developers to meet tight power budgets in designs
for wearables or other personal electronics. For example,
developers can set the AD8233 in a low-power mode,
consuming less than 1μA of supply current, rapidly returning to
full-power mode when electrodes are detected
(Figure 2).
System Power Optimization
The ability to tune designs for specific power and performance
targets is an essential feature for every component in an IoT
design. Perhaps nowhere is this capability more important
than in the design's MCU, which typically accounts for most
power consumption in any system. With an MCU, the need to
maintain some level of functionality has traditionally complicated
13
Figure 1: Designers need few additional components to implement
sensor designs with Analog Devices' AD7124-4, even using an analog
pin to drive the excitation current needed with resistive sensors while
using other analog inputs for sensor voltage measurement and for
reference voltage measurement in ratiometric conversion.
(Source: Analog Devices)
Figure 2: Application-specific AFEs such as Analog Devices'
AD8233 support low-power design with capabilities such as quickly
transitioning to active mode upon detection of electrodes.
(Source: Analog Devices)
EVAL-ADICUP3029 Development
Learn More
4
• ADuCM3029 Ultra Low Power ARM
Cortex-M3 MCU with Integrated Power
Management
• Arduino Uno R3, Pmod, and Grove I2C
compatible connectors
• Low energy Bluetooth and
Wi-Fi connectivity
IoT
