HAF Datasheet, PDF (1/6 Pages) Honeywell Solid State Electronics Center – HONEYWELL ZEPHYR DIGITAL AIRFLOW SENSORS: HAF SERIES-HIGH ACCURACY

™
DESCRIPTION
Honeywell Zephyr™ Digital Airflow Sensors: HAF Series-High
Accuracy, provide a digital interface for reading airflow over the
specified full scale flow span and temperature range. Their
thermally isolated heater and temperature sensing elements
help these sensors provide a fast response to air or gas flow.
Zephyr sensors are designed to measure mass flow of air and
other non-corrosive gases. They are available in standard flow
ranges and are fully calibrated and temperature compensated
with an on-board Application Specific Integrated Circuit (ASIC).
The HAF Series is compensated over the temperature range of
0 C to 50 C [32 F to 122 F] and operates across a
temperature range of -20 C to 70 C [-4 F to 158 F]. The
state-of-the-art ASIC-based compensation provides digital (I²C)
outputs with a response time of 1 ms.
These sensors operate on the heat transfer principle to
measure mass airflow. They consist of a microbridge
Microelectronic and Microelectromechanical System (MEMS)
with temperature-sensitive resistors deposited with thin films of
platinum and silicon nitride. The MEMS sensing die is located
in a precise and calculated airflow channel to provide
repeatable flow response.
Zephyr sensors provide customers with enhanced reliability,
digital accuracy, repeatable measurements and the ability to
customize sensor options to meet many specific application
needs. The combination of rugged housings with a stable
substrate makes these products extremely robust. They are
designed and manufactured according to ISO 9001 standards.
FEATURES AND BENEFITS (= competitive differentiator)
High ±2.5% accuracy allows for very precise airflow
measurement, often ideal for demanding applications with
high accuracy requirements
Full calibration and temperature compensation typically allow
customer to remove additional components associated with
signal conditioning from the PCB, reducing PCB size as well
as costs often associated with those components (e.g.,
acquisition, inventory, assembly)
Customizable for specific end-user needs
High sensitivity at very low flows allows a customer’s
application to detect presence or absence of airflow
High stability reduces errors due to thermal effects and null
shift to provide accurate readings over time, often eliminating
need for system calibration after PCB mount and periodically
over time
Low pressure drop typically improves patient comfort in
medical applications, and reduces noise and system wear on
other components such as motors and pumps
Linear output provides more intuitive sensor signal than the
raw output of basic airflow sensors, which can help reduce
production costs, design, and implementation time
Fast response time allows a customer's application to
respond quickly to airflow change, important in critical
medical (i.e., anesthesia) and industrial (i.e., fume hood)
applications
High 12-bit resolution increases ability to sense small airflow
changes, allowing customers to more precisely control their
application
Low 3.3 Vdc operating voltage option and low power
consumption allow for use in battery-driven and other
portable applications
ASIC-based I²C digital output compatibility eases integration
to microprocessors or microcontrollers, reducing PCB
complexity and component count
Bidirectional flow sensing capability eliminates the need for
two airflow sensors, helping to reduce production costs and
implementation time
Insensitivity to mounting orientation allows customer to
position sensor in most optimal point in the system,
eliminating concern for positional effects
Insensitivity to altitude eliminates customer-implemented
altitude adjustments in the system, easing integration and
reducing production costs by not having to purchase
additional sensors for altitude adjustments
Small size occupies less space on PCB, allowing easier fit
and potentially reducing production costs; PCB size may
also be reduced for easier fit into space-constrained
applications
RoHS-compliant materials meet Directive 2002/95/EC