HS1101LF – Relative Humidity Sensor
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• Lead free component
• High reliability and long term stability
• Patented solid polymer structure
• Suitable for linear voltage or frequency output
circuitry
• Fast response time and very low temperature
coefficient
DESCRIPTION
Based on a unique capacitive cell, these relative humidity sensors are designed for high volume, cost sensitive
applications such as office automation, automotive cabin air control, home appliances, and industrial
process control systems. They are also useful in all applications where humidity compensation is needed.
FEATURES APPLICATIONS
• Full interchangeability with no calibration
required in standard conditions • Automotive
• Instantaneous desaturation after long periods in
saturation phase • Home Appliance
• Compatible with automatized assembly
processes, including Pb free wave soldering
and reflow processes
(1)
• Printers
• Meteorology
• Individual marking for compliance to stringent
traceability requirements
• Part may be washed with distilled water
PERFORMANCE SPECS
MAXIMUM RATINGS
Peak conditions: less than 10% of the operating time.
Ratings
Symbol
Value
Unit
Operating Temperature Ta -60 to 140 °C
Storage Temperature Tstg -60 to 140 °C
Supply Voltage (Peak) Vs 10 Vac
Humidity Operating Range RH 0 to 100 % RH
HS1101LF – Relative Humidity Sensor
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ELECTRICAL CHARACTERISTICS OF HUMIDITY SENSOR
(Ta=25°C, measurement frequency @10kHz / 1V unless otherwise noted)
(1) Tighter specification available on request
TYPICAL PERFORMANCE CURVES
POLYNOMIAL RESPONSE OF HS1101LF
C (pF)=C@55 %*( 3.903 10
-8
*RH
3
-8.294 10
-6
*RH
2
+2.188 10
-3
*RH+0.898)
TYPICAL RESPONSE LOOK-UP TABLE (POLYNOMIAL REFERENCE CURVE) @ 10KHZ / 1V
RH (%) 0 5 10 15 20 25 30 35 40 45 50
Cp (pF) 161.6 163.6 165.4 167.2 169.0 170.7 172.3 173.9 175.5 177.0 178.5
RH (%) 55 60 65 70 75 80 85 90 95 100
Cp (pF) 180 181.4 182.9 184.3 185.7 187.2 188.6 190.1 191.6 193.1
REVERSE POLYNOMIAL RESPONSE OF HS1101LF
RH (%) = -3.4656 10
+3
*X
3
+1.0732 10
+4
*X
2
-1.0457 10
+4
*X+3.2459 10
+3
)
With X=C(read) / C@55%RH
MEASUREMENT FREQUENCY INFLUENCE
In this data sheet, all capacitance measurements are done @ 10 kHz / 1Volt. However, the sensor can operate
without restriction from 5 kHz to 300 kHz.
Characteristics
Symbol
Min
Typ
Max
Unit
Humidity Measuring Range RH 1 99 %RH
Supply Voltage Vs 10 V
Nominal capacitance @55%RH
(1)
C 177 180 183 pF
Temperature coefficient T
cc
-0.01 pF/°C
Average Sensitivity from 33% to 75%RH ∆C/%RH 0.31 pF/%RH
Leakage Current (Vcc=5V) I 1 nA
Recovery time after 150 hours of condensation tr 10 s
Humidity Hysteresis +/-1 %RH
Long term stability T +/-0.5 %RH/yr
Time Constant (at 63% of signal, still air) 33%RH to 80%RH ta 3 5 s
Deviation to typical response curve (10% RH to 90%RH) +/-2 %RH
HS1101LF – Relative Humidity Sensor
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POLARISATION
In order to get a better reproducibility during measurements, always connect the case of the header (pin 2) to
the ground of the circuit. The case of the header is located on the opposite side of the tab.
SOLDERING INSTRUCTIONS
We recommend taking specific attention to soldering conditions to get the best performance of MEAS-
France/Humirel sensors. See Application Note. To get it, please contact: humirel.application@meas-spec.com.
PROPORTIONAL VOLTAGE OUTPUT CIRCUIT
BLOCK DIAGRAM
FREQUENCY OUTPUT CIRCUIT
CIRCUIT
Note: R22=499kΩ / R4=49.9kΩ / R1=1 kΩ / RV1=50 kΩ potentiometer / C1=10nF / C2=2.2nF / C3=100nF
HS1101LF – Relative Humidity Sensor
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This circuit is the typical astable design for 555. The HS1101LF, used as variable capacitor, is connected to the
TRIG and THRES pin. Pin 7 is used as a short circuit pin for resistor R4.
The HS1101LF equivalent capacitor is charged through R22 and R4 to the threshold voltage (approximately
0.67Vcc) and discharged through R22 only to the trigger level (approximately 0.33Vcc) since R4 is shorten to
ground by pin 7.
Since the charge and discharge of the sensor run through different resistors, R22 and R4, the duty cycle is
determined by: thigh = C@%RH*(R22+R4)*ln2
tlow= C@%RH*R22*ln2
F = 1/(thigh+tlow) = 1/(C@%RH*(R4+2*R22)*ln2)
Output duty cycle = thigh*F = R22/(R4+2*R22)
To provide an output duty cycle close to 50%, R4 should be very low compared to R22 but never under a
minimum value. Resistor R3 is a short circuit protection. 555 must be a CMOS version.
TYPICAL RESPONSE LOOK-UP TABLE
RH (%) 0 5 10 15 20 25 30 35 40 45 50
Fout (Hz)
- -
7155 7080 7010 6945 6880 6820 6760 6705 6650
RH (%) 55 60 65 70 75 80 85 90 95 100
Fout (Hz) 6600 6550 6500 6450 6400 6355 6305 6260 6210
-
MEASUREMENT ERROR VS STRAY CAPACITANCE
• Special attention is required in order to minimize stray capacitance in the layout. The added capacitance will
act as a parallel capacitance with the sensor and create a measurement error.
• A careful coating of PCB and components must be implemented to prevent unexpected deviations of Fout in
high humidity conditions.
HS1101LF – Relative Humidity Sensor
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QUALIFICATION PROCESS
HS1101LF sensors have been qualified through a complete qualification process taking in account
many of the requirements of the JEDEC standard including:
Solder heat and solderability including lead free process
Pb free wave soldering and reflow soldering process(260°C) + DI water clean at 45°C
Mechanical shock JESD-22-B104-A
Vibration - Variable frequency(20 to 2000Hz) JESD-22-B103-A
Marking permanency
ESD - Electrostatic Discharge –Air Gun +-15kV(IEC 1000)
Salt Atmosphere JESD22-A107-A
Temperature Cycling - 40°C / +125°C
High Temperature / Humidity Operating Life - 93%RH / 60°C for 1000 hours
Low Humidity storage life - RH < 10%/23°C for 1000 hours
Resistance to immersion in water at ambient temperature and 80°C
High temperature storage 140°C for 168 hours
Resistance to many chemicals linked to home appliances/automotive or consumer
applications
PACKAGE OUTLINE
Dim Min (mm) Max (mm)
A 9.70 10.20
B 5.70 6.20
C 0.40 0.60
D 12.00 14.00
E 0.40 0.50
G 45° BCS
H 0.70 1.10
J 0.70 0.90
K 4.83 5.33
HS1101LF – Relative Humidity Sensor
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ORDERING INFORMATION
HPP801A031 (MULTIPLE PACKAGE QUANTITY OF 48 PIECES)
HS1101LF - CAPACITIVE RELATIVE HUMIDITY SENSOR
To distinguish HS1101 from HS1101LF, HS1101LF is designed with a black plastic cap
Sample kit of HS1101LF is available through MEASUREMENT SPECIALTIES web site:
http://www.meas-spec.com/humidity-sensors.aspx
Revision Comments Who Date
E Deletion of “HS1100LF” reference into the document D. LE GALL April 07
F Physical drawing change (before too fuzzy to read) D. LE GALL May 07
G Standardized datasheet format D. LE GALL April 08
H Temperature Coefficient adjustment D. LE GALL March 11
I New MEAS template, MEAS-France contact details
updated D. LE GALL-ZIRILLI October 12
The information in this sheet has been carefully reviewed and is believed to be accurate; however, no responsibility is assumed for
inaccuracies. Furthermore, this information does not convey to the purchaser of such devices any license under the patent rights to the
manufacturer. Measurement Specialties, Inc. reserves the right to make changes without further notice to any product herein. Measurement
Specialties, Inc. makes no warranty, representation or guarantee regarding the suitability of its product for any particular purpose, nor does
Measurement Specialties, Inc. assume any liability arising out of the application or use of any product or circuit and specifically disclaims
any and all liability, including without limitation consequential or incidental damages. Typical parameters can and do vary in different
applications. All operating parameters must be validated for each customer application by customer’s technical experts. Measurement
Specialties, Inc. does not convey any license under its patent rights nor the rights of others.
Customer Service contact details
Measurement Specialties, Inc - MEAS France
Impasse Jeanne Benozzi
CS 83 163
31027 Toulouse Cedex 3
FRANCE
Tél: +33 (0)5 820 822 02
Fax: +33(0)5 820 821 51
Sales: humidity.sales@meas-spec.com
