humidity sensors
DESCRIPTION
Humidity Sensors. Relative Humidity Sensor Technology Comparison. Four types of humidity sensors Capacitive: The best RH sensor; low cost Resistive: Lowest cost; declining market share Tin oxide: Poor interchangeability and stability Aluminum oxide: Used in ultra-low RH conditions - PowerPoint PPT PresentationTRANSCRIPT
Copyright ©2008 Honeywell International Inc. All rights reserved.
Humidity Sensors
Honeywell.com
• Four types of humidity sensors– Capacitive: The best RH sensor; low cost
– Resistive: Lowest cost; declining market share
– Tin oxide: Poor interchangeability and stability
– Aluminum oxide: Used in ultra-low RH conditions
• Honeywell’s HIH-Series use capacitive RH sensing plus circuitry– Thermoset polymer capacitor is more rugged
– Laser trimming provides enhanced interchangeability
– Relative Humidity Integrated Chip (RHIC) provides on-chip signal conditioning with the capacitor
Relative Humidity Sensor Technology Comparison
Thermoset polymer capacitor solution uses capacitive relative humidity sensing and circuitry to provide the best humidity range and lowest cost implementation.
Honeywell.com
Honeywell’s HIH Series Humidity Sensors
• HIH Series of relative humidity sensing products are solid-state devices designed to offer a pre-packaged, small and highly accurate method of detecting the percentage of relative humidity.
• How the Complimentary Metal Oxide Semiconductor (CMOS)- based RH sensor works:– As the bottom thermoset polymer layer absorbs water, the dielectric of the
capacitor and the observed capacitance increases.
– The upper thermoset polymer layer provides additional physical protection.
– Thermoset polymers provide much better environmental resistance than typical thermoplastic polymers.
Honeywell.com
Honeywell’s HIH Series Portfolio
• Wide relative humidity sensing range• Enhanced accuracy• Enhanced response time• Excellent, laser-trimmed 5% interchangeability • Ratiometric, near-linear analog voltage output vs. %RH• Chemically resistant• Stable, low-drift performance• Low current draw (typical 200 µA)• Operating temperature range: -40 °C to 85 °C• Supply voltage required: 4 Vdc to 5.8 Vdc• RoHs compliant
Honeywell.com
Relative Humidity Sensor Potential Applications
• HVAC– Humidistats
– Commercial and residential building controls
– Humidifiers
– Dehumidifiers
– Enthalpy sensors
– Fan systems
• Additional applications– Transport and stationary
container refrigeration systems
– Medical respiratory and incubator equipment
– Weather stations/radiosondes
– Telecommunications cabinets
– Office automation
– Drying equipment
– Air compressors
– Processing/packaging equipment
Honeywell.com
HIH-4000 Series Humidity Sensors
• SIP packages with 0.1 and 0.05 inch lead spacing
• Uncovered
• Lowest cost solution for CMOS type
• Mounts directly into PCBs
• 5% interchangeability (0% RH to 59% RH)
• Optional calibration data available
• Effective August 4, 2008, the HIH-4000 will adopt the same lead frame as that used on the HIH-4010 series
Honeywell.com
HIH-4602-A/C Series Temperature/Humidity Sensors
• TO-5 can package• Hydrophobic sintered stainless steel filter provides enhanced
sensor protection• On-board temperature sensor for direct temperature output• “A” version features a 100 kOhm thermistor• “C” version features 1k ohm platinum RTD• 5% interchangeability (0 to 59% RH)• Includes calibration data• Often ideal for dew point and absolute humidity/moisture
measurements
60µ pore hydrophobic sintered SST filter
Honeywell.com
HIH-4602-L Harsh Environment Sensor
• TO-39 can package• Slotted cap enables fast response while maintaining the
robustness of an enclosed component• On-board RTD temperature sensor for direct temperature
output• 5% interchangeability (between 0 to 59%RH)• Calibration data available with HIH-4602-L-CP
Honeywell.com
HIH-4010/4020/4021 Series Humidity Sensors
• HIH-4010: uncovered, SIP with 0.05 or 0.1 inch leads• HIH-4020: covered with 0.05 or 0.1 inch leads• HIH-4021: covered, condensation-resistant with 0.05 or 0.1 inch
leads• 5% interchangeability (0 to 59% RH)• Optional calibration data available• Smaller plastic package as compared to HIH-4000 • Faster response time (5 sec) as compared to HIH-4000 (15 sec)• Effective August 4, 2008, HIH-4000 will adopt same lead frame as that
used on HIH-4010 Series
HIH-4010 HIH-4020 HIH-4021
Honeywell.com
HIH-4010/4020/4021
+ =
+ =
Hydrophobic Filter
+
+
=
=
Filter is glued onto cover
Filter is glued onto
cover
HIH-4010-002 Cover HIH-4020-002Proposed P/N
50004018 HIH-4021-002
HIH-4010-001Cover
HIH-4020-001
Hydrophobic Filter
Proposed P/N 50004018 HIH-4021-001
Honeywell.com
HIH-4030/4031 Series Humidity Sensors
• HIH-4030: uncovered, surface mount (SMD)• HIH-4031: covered, surface mount (SMD)• Supplied in 1000 piece, tape and reel packaging (often ideal for
high volume applications)• SMD packaging on tape and reel allows for use in high volume,
automated pick and place manufacturing, eliminating lead misalignment to printed circuit board through-hole and lowers OEM manufacturing process cost
• 5% interchangeability (0 to 59% RH)• Optional calibration data available• Sample packs available for stocking: HIH-4030-001S,
-003S, HIH-4031-001S, -003S
Honeywell.com
HCH-1000 Series Humidity Sensors
• HCH-1000-001: uncased, capacitive-output with 0.1 inch lead pitch• HCH-1000-002: cased, capacitive-output with 0.1 inch lead pitch (for
dust protection/handling during OEM assembly)• Capacitive polymer sensor consists of a grid top electrode, a
polyimide layer, and a bottom electrode (grid top electrode on the bottom provides enhanced sensitivity)
• No active signal conditioning on board = capacitance type (pF) output• 2% hysteresis/linearity, typical• Operating temperature range: -40 °C to 120 °C• Often ideal for high-volume, cost-sensitive applications where
capacitance output is acceptable (i.e., ≤ $2 target price)• RoHs compliant
HCH-1000-002 HCH-1000-001
Copyright ©2008 Honeywell International Inc. All rights reserved.
Applying Humidity Sensors
Honeywell.com
Ratiometric Output
• The output voltage is proportional to the supply voltage in a set ratio
• For example, the device output at 5 Vdc supply will typically be 0.8 Vdc to 3.9 Vdc
Honeywell.com
Typical Sensor OutputTypical Sensor Output over RH Range
y = 0.03x + 0.7172
R2 = 0.9978
0
0.5
1
1.5
2
2.5
3
3.5
4
0 10 20 30 40 50 60 70 80 90 100
%RH
De
vice
Ou
tpu
t (V
olta
ge
)
Sensor OutputLinear (Sensor Output)
Honeywell.com
Interchangeability
What does Interchangeability = ±5% at 0% RH mean?
• Defines the range of voltages for any population of sensors at this RH point. – This is compared to the baseline output for the RHIC chip, which is 0.8 V to 3.9
V (0 to 100% RH) with a supply voltage of 5 Vdc.
• If you take the typical slope*, 0.031 V/%RH times ±5%RH you get ±0.155 V.
• This means that the output voltage for this device is 0.8 V ±0.155 V or a range of 0.645 V to 0.955 V.
• When exposed to an RH of 0%, the output of the entire population of sensors will fall within this range.
• The interchangeability increases with increasing RH since the RHIC die is actively trimmed only at 0% RH. Trimming at other RH values is impractical.
*Typical slope = (3.9V - 0.8V)/100% RH = 0.031V/%RH
Honeywell.com
Interchangeability and Accuracy
0%RH
• Interchangeability at 0% RH– Interchangeability lets you lower design costs by avoiding calibrating
your system to each individual sensor. – The RHIC sensor keeps its interchangeability and accuracy advantages
at higher humidity.
• Accuracy at 0% RH– Accuracy = Interchangeability ±5% when you don’t calibrate your
system to each sensor.
Honeywell.com
Temperature Effects
Typical Effects of Temperature
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0 20 40 60 80 100
%RH
Dev
ice
Ou
tpu
t (V
olt
age)
0C
25C
50C
70C
Honeywell.com
Humidity Application Questions
• What is the operating temperature range?• What is the storage temperature range?• What is the operating humidity range?• What accuracy is needed from the sensor?• Is there a required output from the sensor other than voltage?• Is there a preference with SIP or surface mount (SMD)?• Will there be condensation in the application?
– (Preface condensation questions that the device is specified for non-condensing environments today.)
– How many condensation cycles?– Does the sensor need to function while in a condensing environment?
• Timing of the project? • What is the price target? • What is the volume and ramp up scenario?• Who is the competitor and do we know their part number?
Honeywell.com
Humidity Sensors Contact Information
• Product Manager – Valerie Rothermel-Nelson– [email protected]
• Application Engineer – Bob Ward– [email protected]
• Thermal applications (Europe) – Alex Geddes– [email protected]
• Thermal applications (Asia-Pacific) David Rong– [email protected]
• General technical support and product cross reference– 1-800-537-6945 – [email protected]