By Majeed Ahmad, contributing editor

digital-to-analog converter (DAC) is the latest component getting a makeover in
the Industry 4.0 arena, and Texas Instruments’ DAC8775 with integrated buck/boost
converter just shows the drift.

because factory automation and process control engineers increasingly need to
pack more channels into a smaller space due to the rising number of sensors.
But it’s becoming unmanageable because of greater power losses, which raise
system temperature, reduce device reliability, and increase failure rate.

The I/O modules cannot squeeze more channels in a
small space without significant design trade-offs because precision DACs lack
thermal efficiency and diagnostic features. Moreover, the need for multiple
power supplies catering to multiple I/O channels leads to larger board space.

What TI’s 4- to 20-mA DAC does is combine the precision performance with a simpler power supply
design. A single 12- to 36-V power supply accommodates all needed internal power supplies, and that saves cost as well as
board area.

an adaptive power management system facilitated by a single power supply and
integrated buck/boost converter lowers the power dissipation. TI’s DAC8775
helps create an adaptive power management system by making an intelligent
decision on whether to buck or boost the supply.

DAC8775 chip employs a buck/boost converter to supply just the necessary power
to the load. It dynamically adjusts the generated supply based on the current
load on the 4- to 20-mA loop, and that
creates a low-power system with a thermally optimized design.


The block diagram of the four-channel DAC8775
for PLCs, sensor transmitters, etc.

Reliability and thermal efficiency

does DAC8775 enhance reliability in industrial control systems? For starters,
it operates in the extended industrial temperature range of –40°C to 125°C
without requiring the temperature de-rating.

DAC8775 features alarms that monitor conditions such as open load, short
circuit, overtemperature, and cyclic redundancy check (CRC). The diagnostic
features are comprised of alarm action registers that provide designers with
flexible options to manage equipment conditions.

is targeting its new DAC at analog outputs used in PLC modules, sensor
transmitters, and industrial and building automation equipment. The DACs can be
used to deliver either a voltage output or current output.

has also made available a four-channel analog output module reference design
using the DAC8775 and the LM5166 high-efficiency synchronous buck converter.
The chipmaker claims that this design solution dissipates less than 1 W in
factory automation implementations.

Find out more about the DAC8775.