HS1101LF Relative Humidity Sensor 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 maximum ratings Lead Free Components Ratings Full Interchangeability with no calibration required in standard conditions Symbol Value Unit 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 Operating Temperature Instantaneous desaturation after long periods in saturation phase Compatible with automatized assembly processes, including Pb free wave soldering and reflow processes (1) Operating Range High Reliability and Long Term Stability 100 90 80 Patented Solid Polymer Structure Relative Humidity in % RH 70 Suitable for linear voltage or frequency output circuitry Fast response time and very low temperature coefficient 60 50 40 30 20 Part may be washed with distilled water 10 0 -60 -40 -20 0 20 40 60 80 100 Temperature in °C Individual marking for compliance to stringent traceability requirements (1) Soldering temperature profiels available upon request/contact us at [email protected] Measurement Specialties, Inc. 1000 Lucas Way Hampton, VA 23666 USA -1- www.meas-spec.com 757-766-1500 800-745-8008 Fax 757-766-4297 120 140 160 HS1101LF Relative Humidity Sensor C h a r a c t e r i s t i c s ( Ta = 2 5 º C , m e a s u re m e n t f re q u e n c y @ 1 0 k H z u n l e s s o t h e r w i s e s t a t e d ) Characteristics Symbol Min Humidity metrology range RH 1 Voltage supply Vs Nominal capacitance @ 55% RH C Temperature coefficient Typ 177 180 Tcc Unit 99 % RH 10 V 183 pF 0.01 C /% RH Averaged Sensitivity from 33% to 75% RH Max pF/°C 0.31 Leakage current (Vcc=5 Volts) I Recovery time after 150 hours of condensation tr 10 t +/-0.5 pf/% RH 1 nA s Humidity Hysteresis +/-1 Long term stability τα Time constant (33 to 80% RH, still air, @ 63%) 3 Deviation to typical response curve (10% to 90%) RH) % RH % RH/yr 5 s +/-2 % RH Ty p i c a l re s p o n s e l o o k - u p t a b l e ( P o l y n o m i a l R e f e re n c e c u r v e ) 1 0 k H z / 1 V 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 Polynomial response of HS1101LF: C (pF)=C@55 %*( 3.903 10-8 *RH3-8.294 10-6 *RH2+2.188 10-3 *RH+0.898) Reversed Polynomial response of HS1101LF: RH (%) = -3.4656 10+3 *X3+1.0732 10-4 *X2-1.0457 10+4 *X+3.2459 10+3 With X=C(read) / C@55%RH P ro p o r t i o n a l Vo l t a g e O u t p u t C i rc u i t Block Diagram Measurement Specialties, Inc. 1000 Lucas Way Hampton, VA 23666 USA -2- www.meas-spec.com 757-766-1500 800-745-8008 Fax 757-766-4297 HS1101LF Relative Humidity Sensor F re q u e n c y O u t p u t C i rc u i t s Note: R22=499kS / R4=49.9S? / R1=1 kS / RV1=50 kS potentiometer / C1=10nF / C2=2.2nF / C3=100nF 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. Ty p i c a l re s p o n s e l o o k - u p t a b l e ( H u m i d i t y O u t p u t ) RH (%) 0 5 Fout (Hz) RH (%) Fout (Hz) 10 15 20 25 30 35 40 45 50 7155 7080 7010 6945 6880 6820 6760 6705 6650 100 55 60 65 70 75 80 85 90 95 6600 6550 6500 6450 6400 6355 6305 6260 6210 Measurement Specialties, Inc. 1000 Lucas Way Hampton, VA 23666 USA -3- www.meas-spec.com 757-766-1500 800-745-8008 Fax 757-766-4297 HS1101LF Relative Humidity Sensor M e a s u re m e n t E r ro r v s S t r a y C a p a c i t a n c e -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. Q u a l i f i c a t i o n P ro c e s s 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 - 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. ENVIRONMENTAL AND RECYCLING HS1101LF sensors are lead free components and are compatible with Pb Free soldering processes. HS1101LF sensors are free from Cr (6+), Cd and Hg. O rd e r i n g I n f o r m a t i o n : H S 1 1 0 1 L F Package Outline HS1101LF HS1101LF: HPP801A031 (MULTIPLE PACKAGE QUANTITY OF 48 PIECES) CAPACITIVE RELATIVE HUMIDITY SENSOR. Dimensions in millimeters Measurement Specialties, Inc. 1000 Lucas Way Hampton, VA 23666 USA -4- www.meas-spec.com 757-766-1500 800-745-8008 Fax 757-766-4297 HS1101LF-0407