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
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Full interchangeability with no calibration
required in standard conditions
Instantaneous desaturation after long periods in
saturation phase
Compatible with automatized assembly
processes, including Pb free wave soldering
(1)
and reflow processes
Individual marking for compliance to stringent
traceability requirements
Part may be washed with distilled water
APPLICATIONS
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Automotive
Home Appliance
Printers
Meteorology
PERFORMANCE SPECS
MAXIMUM RATINGS
Ratings
Operating Temperature
Storage Temperature
Supply Voltage (Peak)
Humidity Operating Range
Symbol
Ta
Tstg
Vs
RH
Value
-60 to 140
-60 to 140
10
0 to 100
Unit
°
C
°
C
Vac
% RH
Peak conditions:
less than 10% of the operating time.
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HS1101LF – Relative Humidity Sensor
ELECTRICAL CHARACTERISTICS OF HUMIDITY SENSOR
(Ta=25° measurement frequency @10kHz / 1V unless otherwise noted)
C,
Characteristics
Humidity Measuring Range
Supply Voltage
(1)
Nominal capacitance @55%RH
Temperature coefficient
Average Sensitivity from 33% to 75%RH
Leakage Current (Vcc=5V)
Recovery time after 150 hours of condensation
Humidity Hysteresis
Long term stability
Time Constant (at 63% of signal, still air) 33%RH to 80%RH
Deviation to typical response curve (10% RH to 90%RH)
(1)
Tighter specification available on request
Symbol
RH
Vs
C
T
cc
∆C/%RH
I
tr
T
ta
Min
1
177
Typ
180
-0.01
0.31
10
Max
99
10
183
1
+/-1
+/-0.5
3
+/-2
5
Unit
%RH
V
pF
pF/°C
pF/%RH
nA
s
%RH
%RH/yr
s
%RH
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 (%)
Cp (pF)
RH (%)
Cp (pF)
0
161.6
55
180
5
163.6
60
181.4
10
165.4
65
182.9
15
167.2
70
184.3
20
169.0
75
185.7
25
170.7
80
187.2
30
172.3
85
188.6
35
173.9
90
190.1
40
175.5
95
191.6
45
177.0
100
193.1
50
178.5
REVERSE POLYNOMIAL RESPONSE OF HS1101LF
RH (%) = -3.4656 10 *X +1.0732 10 *X -1.0457 10 *X+3.2459 10 )
With X=C(read) / C@55%RH
+3
3
+4
2
+4
+3
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.
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HS1101LF – Relative Humidity Sensor
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=499k
/ R4=49.9k
/ R1=1 k
/ RV1=50 k
potentiometer / C1=10nF / C2=2.2nF / C3=100nF
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HS1101LF – Relative Humidity Sensor
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 (%)
Fout (Hz)
RH (%)
Fout (Hz)
0
5
10
7155
65
6500
15
7080
70
6450
20
7010
75
6400
25
6945
80
6355
30
6880
85
6305
35
6820
90
6260
40
6760
95
6210
45
6705
100
50
6650
-
55
6600
-
60
6550
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MEASUREMENT ERROR VS STRAY CAPACITANCE
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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.
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HS1101LF – Relative Humidity Sensor
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° + DI water clean at 45°
C)
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° for 1000 hours
C
Low Humidity storage life - RH < 10%/23° for 1000 hours
C
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
A
B
C
D
E
G
H
J
K
Min (mm)
9.70
5.70
0.40
12.00
0.40
Max (mm)
10.20
6.20
0.60
14.00
0.50
45° BCS
0.70
0.70
4.83
1.10
0.90
5.33
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