HTM1735LF – Temperature and Relative Humidity Module
HTM1735LF HPC035_K www.meas-spec.com May 2008
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• Suitable for direct board assembly
• Product free from Lead, Cr (6+), Cd and Hg
• Humidity calibrated within +/- 2% RH @ 55% RH
• Typical 1 to 3.6 Volt DC output for 0 to 100% RH at
5V DC supply
• Temperature measurement through NTC 10 kΩ +/-
3% direct output
DESCRIPTION
Based on the rugged HS1101LF humidity sensor, HTM1735LF is a dedicated humidity and temperature
transducer designed for OEM applications where a reliable and accurate measurement is needed. Direct
interface with a micro-controller is made possible with the module’s humidity linear voltage and direct NTC
outputs. HTM1735LF is designed for an optimized board to board connection.
FEATURES APPLICATIONS
• Full interchangeability • Reprography
• High reliability and long term stability • HVAC Controller
• Not affected by repeated condensations …
• Ratiometric to voltage supply within the
specified range
PERFORMANCE SPECS
MAXIMUM RATINGS
Ratings Symbol Value Unit
Storage Temperature Tstg -40 to 105 °C
Storage Humidity RHstg 0 to 100 % RH
Supply Voltage (Peak) Vs 7 Vdc
Humidity Operating Range RH 0 to 100 % RH
Temperature Operating Range Ta -40 to 100 °C
Maximum Output Current (Peak) IPeak 5 mA
Maximum Power Pd 20 mW
HTM1735LF – Temperature and Relative Humidity Module
HTM1735LF HPC035_K www.meas-spec.com May 2008
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ELECTRICAL CHARACTERISTICS
(Ta=25°C, Vs=5Vdc, RL>1MΩ unless otherwise stated)
(1) At 2m/s air flow
(Ta=25°C)
TYPICAL PERFORMANCE CURVES
HUMIDITY SENSOR
• Measurement Conditions
HTM1735LF is specified for accurate
measurements within 10 to 95 %RH.
Excursion out of this range (< 10% or > 95% RH,
including condensation) does not affect the
reliability of HTM1735LF characteristics
Humidity Characteristics Symbol Min Typ Max Unit
Humidity Measuring Range RH 0 100 %RH
Relative Humidity Accuracy (10 to 95% RH) RH +/-3 +/-5 %RH
Supply Voltage Vs 4.75 5.00 5.25 Vdc
Nominal Output @55%RH (at 5Vdc) Vout 2.42 2.48 2.54 V
Current Consumption Ic 2.8 4 mA
Temperature Coefficient (10 to 50°C) Tcc -0.05 -0.1 %RH/°C
Average Sensitivity from 33% to 75%RH ΔVout/ΔRH +26 mV/%RH
Sink Current Capability (RL = 33kΩ) I 150 µA
Recovery Time after 150 hours of condensation tr 10 s
Humidity Hysteresis +/-1 %RH
Humidity Resolution 0.4 %RH
Long Term Stability T +/-0.5 %RH/yr
Time Constant (at 63% of signal, static) 33% to 75%RH (1) τ 5 10 s
Output Impedance Z 70 Ω
Warm Up Time tW 200 ms
Temperature Characteristics Symbol Min Typ Max Unit
Nominal Resistance @25°C R 10 kΩ
Beta value: B25/100 β 3600 3730 3800
Temperature Measuring Range Ta -30 80 °C
Nominal Resistance Tolerance @25°C RN 2 3 %
Beta Value Tolerance β 3 %
Response Time τ 10 s
HTM1735LF – Temperature and Relative Humidity Module
HTM1735LF HPC035_K www.meas-spec.com May 2008
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• HTM1735LF Modeled Linear Voltage Output (Vcc=5V)
LINEAR EQUATION:
Vout = 25.68RH + 1079
RH = 0.03892 Vout – 41.98
(With Vout in mV and RH in %)
• Error Budget Conditions
• Linearity Error
RH (%) Vout (mV) RH (%) Vout (mV)
10 1325 55 2480
15 1465 60 2605
20 1600 65 2730
25 1735 70 2860
30 1860 75 2990
35 1990 80 3125
40 2110 85 3260
45 2235 90 3405
50 2360 95 3555
LINEAR EQUATION
1000
2000
3000
4000
0 102030405060708090100
Relative Humidity (%)
Output Voltage (mV)
HTM1735LF – Temperature and Relative Humidity Module
HTM1735LF HPC035_K www.meas-spec.com May 2008
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TEMPERATURE SENSOR
• Typical temperature output
Depending on the needed temperature measurement range and associated accuracy, we suggest two methods
to access to the NTC resistance values.
RT NTC resistance in Ω at temperature T in K
RN NTC resistance in Ω at rated temperature T in K
T, TN Temperature in K
β Beta value, material specific constant of NTC
e Base of natural logarithm (e=2.71828)
c The exponential relation only roughly describes the actual characteristic of an NTC thermistor can, however,
as the material parameter β in reality also depend on temperature. So this approach is suitable for describing a
restricted range around the rated temperature or resistance with sufficient accuracy.
d For practical applications, a more precise description of the real R/T curve may be required. Either more
complicated approaches (e.g. the Steinhart-Hart equation) are used or the resistance/temperature relation as
given in tabulation form. The below table has been experimentally determined with utmost accuracy for
temperature increments of 1 degree.
Actual values may also be influenced by inherent self-heating properties of NTCs. Please refer to MEAS-France
Application Note HPC106 “Low power NTC measurement”.
• Temperature look-up table
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−
×= N
TT
NT eRR
11
β
Temp Resistance Max Deviation Temp Resistance Max Deviation Temp Resistance Max Deviation Temp Resistance Max Deviation
(°C) (Ω)
(Ω)
(°C) (Ω)
(Ω)
(°C) (Ω
)
(Ω)
(°C
)
(Ω
)
(Ω)
-30 144790 16636 -2 33100 2230 26 9600 300 54 3360 213
-29 136664 15444 -1 31557 2078 27 9218 300 55 3237 208
-28 129054 14343 030029 1932 28 8853 299 56 3126 204
-27 121925 13325 128627 1799 29 8506 297 57 3019 200
-26 115243 12383 227299 1675 30 8178 296 58 2917 197
-25 109030 11516 326042 1560 31 7866 294 59 2819 193
-24 103115 10705 424852 1452 32 7568 292 60 2720 189
-23 97565 9953 523773 1355 33 7283 290 61 2629 185
-22 92354 9257 622708 1261 34 7011 287 62 2542 182
-21 87460 8612 721698 1174 35 6734 284 63 2458 178
-20 82923 8020 820739 1093 36 6484 281 64 2378 175
-19 78581 7463 919829 1017 37 6244 278 65 2304 171
-18 74497 6947 10 18959 946 38 6015 275 66 2229 168
-17 70655 6468 11 18128 879 39 5796 271 67 2158 165
-16 67039 6023 12 17338 817 40 5575 267 68 2089 161
-15 63591 5606 13 16588 759 41 5373 264 69 2022 158
-14 60381 5222 14 15876 705 42 5180 260 70 1960 155
-13 57356 4865 15 15207 654 43 4995 257 71 1898 152
-12 54503 4533 16 14569 607 44 4817 253 72 1839 149
-11 51813 4225 17 13962 563 45 4636 248 73 1782 146
-10 49204 3932 18 13384 522 46 4473 245 74 1727 143
-9 46767 3662 19 12834 484 47 4316 241 75 1673 140
-8 44467 3411 20 12280 447 48 4166 237 76 1622 138
-7 42296 3177 21 11777 413 49 4021 233 77 1573 135
-6 40247 2960 22 11297 382 50 3874 229 78 1526 132
-5 38279 2756 23 10840 353 51 3737 225 79 1480 130
-4 36455 2568 24 10404 325 52 3606 221 80 1432 127
-3 34731 2393 25 10000 300 53 3481 217
HTM1735LF – Temperature and Relative Humidity Module
HTM1735LF HPC035_K www.meas-spec.com May 2008
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QUALIFICATION PROCESS
RESISTANCE TO PHYSICAL AND CHEMICAL STRESSES
• HTM1735LFhas passed through qualification processes of MEAS-France including vibration, shock,
storage, high temperature and humidity.
• HTM1735LF contains circuit to protect its inputs and outputs against ElectroStatic Discharges (ESD) up to
±15kV, air discharge.
• Additional tests under harsh chemical conditions demonstrate good operation in presence of salt
atmosphere, SO2 (0.5%), H2S (0.5%), 03, NOx, NO, CO, CO2, Softener, Soap, Toluene, acids (H2SO4,
HNO3, HCI), HMDS, Insecticide, Cigarette smoke, this is not an exhaustive list.
• HTM1735LF is not light sensitive.
SPECIFIC PRECAUTIONS
• HTM1735LF is not protected against reversed polarity - Check carefully when connecting the device.
PACKAGE OUTLINE
PINOUT ASSIGNMENT
Pin Function
1 NTC
–
Tem
p
erature
2 Ground
3 Vcc
–
Volta
g
e su
pp
l
y
4 Vout
–
Humidit
y
HTM1735LF STD PACKAGE OUTLINE
Dim Min (mm) Max (mm)
A 34 36
B 12.5 13.5
C 30.25 Typ
D 5.08 Typ
E 13.1 Typ
Dim Min (mm) Max (mm)
A 34 36
B 12.5 13.5
D 5.08 Typ
F 2.36 Typ
G 3.94 Typ
H Ø 1.02 Typ
Footprint Outline
Footprint (Top View)
3D View
Package Outline
HTM1735LF – Temperature and Relative Humidity Module
HTM1735LF HPC035_K www.meas-spec.com May 2008
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HTM1735LF SMD PACKAGE OUTLINE
Package Outline
Dim Min (mm) Max (mm)
A 34 36
B 12.5 13.5
C 30.25 Typ
D 5.08 Typ
E 6.65 Typ
3D View
Footprint Outline
Dim Min (mm) Max (mm)
F 27.81Typ
G 1.27 Typ
H 3.33 Typ
J 2.04 Typ
K 3.18 Typ
Footprint (Top View)
HTM1735LF SR PACKAGE OUTLINE
Package Outline
Dim Min (mm) Max (mm)
A 34 36
B 12.5 13.5
C 30.25 Typ
D 5.08 Typ
E 6.65 Typ
3D View
HTM1735LF – Temperature and Relative Humidity Module
HTM1735LF HPC035_K www.meas-spec.com May 2008
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ORDERING INFORMATION
HPP805D033: HTM1735LF STD (THROUGH HOLE BOARD-TO-BOARD CONNECTION)
HPP805D034: HTM1735LF SR (WITH HOLES FOR CUSTOMIZED WIRING)
HPP805035: HTM1735LF SMD (SMD BOARD-TO-BOARD CONNECTION)
Customer Service contact details
Measurement Specialties, Inc.
105 av. du Général Eisenhower
BP 23705 31037 TOULOUSE CEDEX 1
FRANCE
Tél: +33 (0) 561 194 848
Fax:+33 (0) 561 194 553
Sales: humidity.sales@meas-spec.com
Revision Comments Who Date
K Standardized datasheet format D.LE GALL May 08
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.
