Servoflo Corp. offers the HYT271 digital humidity element.
This capacitive polymer sensor has an I2C interface and uses an optimized thin
film sensor connected to an ASIC, both on the same substrate.
With a humidity measurement range from 0-100% rH, the HYT271
has an extremely low hysteresis of less than 1% rH with an overall measurement
accuracy of 2.8% rH for the HYT271-S model. The linearity is less than 1% rH
while the resolution is 0.02% rH. A temperature measurement is also included
from -40 to 125°C with an accuracy of 0.3°C and resolution of 0.015°C. Standard
voltage supply is 2.7 to 5.5 V with an optional low voltage model utilizing 1.8
to 3.3 V. The HYT271 has a standard SIL connection with surface mount packaging
available upon request.
Advantages of the HYT271 include the ability to communicate
with as many as 126 sensors at the same time over the I2C interface. Linearity
and temperature drift are factory calibrated, eliminating the need for field
adjustment. The high performance polymer provides excellent stability and
strong resistance to dew formation and chemical exposure.