1-100030 [ETC]
SENSOR HUMIDITY & TEMPERATURE ; 传感器温湿度\n
| 型号： | 1-100030 |
| 厂家： | 
ETC |
| 描述： | SENSOR HUMIDITY & TEMPERATURE
|
| 文件： | 总7页 (文件大小：400K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
AH31
Humidity & Temperature
Sensmitter
_ 2% Accuracy
_ Fully calibrated, digital serial output (SPI)
_ No external components required
_ Ultra low power consumption when
pulsed readout
_ Fast RH response time (4 sec. typical 1/e)
_ Small size
_ Fully interchangeable
_ Immersible
Advance Information as of September 2001
AH31 Product Summary
The AH31 is a Relative Humidity and Temperature Multi
Sensor Module comprising a calibrated digital output.
Application of industrial CMOS processes with
customized post processing (CMOSens technology)
ensures highest reliability and excellent long term
stability. The device includes two calibrated
microsensors for relative humidity and temperature
which are seamlessly coupled to an amplification, analog
to digital conversion and serial interface circuit on the
same chip. This results in superior signal quality, a fast
response time and absolute insensitivity to external
disturbances even immersing the sensmitter into
chemically non-reactive liquids e.g. water, does not
result in any problems.
These coefficients are used internally during
measurement to calibrate the signals from the sensors.
This leads to a full interchangeability of the device by
keeping the accuracy given in the specifications.
The unidirectional SPI compliant 3-wire serial interface
allows easy and fast system integration. Its small
(11x8x3.5mm) size and low power consumption makes it
the ultimate choice for even the most demanding
applications including instrumentation, medical
equipment, heating, ventilation and air conditioning
systems (HVAC), portable consumer electronics,
automotive and battery-operated controllers.
The device is supplied in a surface-mountable ball grid
array (BGA) package.
Each sensmitter is then 2*2 point calibrated in a pre-
cision humidity chamber and the calibration coefficients
are burnt into the OTP memory.
AH31 Single Chip Relative Humidity and Temperature Sensor Module (CMOSensTM technology)
SERIAL NUMBER
MEMORY
CALIBRATION
MEMORY
%RH
SENSOR
MISO
/CS
A/D
SIGNAL
CONDITIONING
CONVERSION
SCK
SPI
INTERFACE
&
CLK
PD
CONTROL
CIRCUITS
A/D
SIGNAL
VDD
GND
CONDITIONING
CONVERSION
TEMP.
SENSOR
www.sensirion.com
Sensirion, Eggbühlstr. 14, 8052 Zürich, Switzerland, Tel: +41 1 306 40 00, Fax: +41 1 306 40 30
SHT11 Relative Humidity & Temperature Sensor System
1 Sensor Performance Specifications
Temperature=25°C, measurement frequency=32kHz, VDD=5V unless otherwise noted
Sensor
Parameter
Conditions
Min.
Typ.
Max.
Units
% RH
% RH
% RH
% RH
% RH
% RH
(1)
(1)
Humidity
Resolution
with enhanced resolution
with enhanced resolution
10 .. 90 % RH
0.1
Reproducibility
0.1
2
(2)
Accuracy
& Interchangeability
Nonlinearity
<10, >90 % RH
4
10 .. 90 % RH uncompensated
0 .. 100 % RH compensated
3
0.2
Range
0
100 % RH
Response time
Hysteresis
1/ e (63 %) in slowly moving air
Typical
4
s
% RH
1
Long term stability
< 1
0.1
0.1
0.9
1.5
% RH/yr
(1)
Temperature Resolution
with enhanced resolution
°C
(1)
Reproducibility
Accuracy
with enhanced resolution
°C
0°C - 60°C
°C
<0°C, >60°C
°C
80 °C
s
Range
-20
Response Time
30
Table 1 Relative Humidity and Temperature Sensor Performance Specifications
1.1 Converting the readout to physical values
1.1.1 Humidity
For temperatures significantly different from 25°C
(~77°F) the temperature coefficient of the RH sensor
should be considered:
To compensate for the non-linearity of the humidity
sensor and to obtain the full accuracy it is
recommended to convert the readout with the following
RHtrue =(T - 25)•(t1 + t2 •SORH ) + RHlinear
°C
(3)
with t1 = 0.01; t2 = 0.00075
1.1.2 Temperature
The temperature sensor is very linear by design.
Use the following formulas or table to convert from
digital readout to temperature:
formula :
2
RHlinear = c1 + c2 •SORH + c3 •SORH
with c1 = -12.84; c2 = 0.68; c3 = -0.0007981
100%
80%
T°c = SOT / 2.55 - 20
T°F = SOT / 1.416 – 4
60%
SPI Readout
(Hex, 8bit)
00
Temperature
40%
20%
0%
-20 °C
80 °C
-4 °F
176 °F
FF
0
50
100
150
200
250
RH
Sensor readout (SPI)
SO
Figure 1 Sensor readout vs. real RH before linearization
(1) See Application Note “Resolution Enhancement” for information on how to achieve resolutions of up to 12bit / 0.1%RH / 0.1°C.
(2) Not including non-linearity
(3) For a simplified conversion formula see application note “RH_Non-Linearity_Compensation”
www.sensirion.com
September 2001 Advance Information
2/7
SHT11 Relative Humidity & Temperature Sensor System
2 Serial Interface
2.2 SPI Pins
30 - 60 kHz
typ. 32 kHz
The unidirectional serial peripheral interface (SPI)
provides an updated 8 bit relative humidity and an 8 bit
xtal
CLK
DO
(2)
temperature output every 512 cycles of CLK.
2.2.1 Clock (CLK)
Quartz
AH31
µC
MISO
DI
This pin provides the clock for the internal sensor
circuitry. See “Figure 2 Typical application circuit”
for a sample circuit. The recommended CLK frequency
is 30 to 60 kHz.
PD
DO
/CS
DO
DO
SCK
DO = Digital Output
DI = Digital Input
CLK generated by µC clock-prescaler or internal counter
2.2.2 Chip Select (/CS)
A low level on this pin selects the device and initiates a
readout operation. /CS has to return to a high level in
between two accesses.
Figure 2 Typical application circuit
Pin Name Comment
As soon as the device is deselected (/CS high level),
MISO changes to the high impedance state, allowing
multiple parts to share the same SPI bus.
1
2
3
4
5
6
7
CLK
/CS
Sensor clock
SPI chip select input
SPI serial clock input
SCK
MISO SPI serial data output
VDD SUPPLY
2.2.3 Serial Output (MISO)
The MISO tristate pin is used to transfer data out of the
device. During a read cycle, data is updated on this pin
after the falling edge and is valid on the rising edge of
the serial clock SCK.
GND Ground
PD
Power down
CKS
NOT USED, MUST BE TIED
8
TO VDD LOCALLY
2.2.4 Serial Clock (SCK)
Table 2 AH31 Pin Description
The SCK is used to synchronize the communication
between a master and the AH31. SCK must remain low
for at least two clock cycles after the falling edge of
/CS. Data on the MISO pin is updated after the falling
edge of the serial clock input.
Unused inputs must always be tied to an appropriate
voltage level (e.g. either VDD or GND)
2.2.5 Readout sequence(3)
8
5
4
6
7
After /CS is low for more than 2 clock cycles the MSB
(most significant bit) of the 8 bit humidity data is
available on the MISO pin. SCK should stay low during
3
2
1
(1)
this time .
Figure 3 AH31 Pin out (bottom view)
After that SCK can run at any speed (< 10 MHz) to shift
out the data.
8 bits of humidity data are followed by 8 bits of
2.1 Power Pins
(2)
temperature data. Transmission is MSB first in both
The AH31 requires a voltage supply between 3.2V and
5.5V. The sensors are calibrated at 5V. In unstable
supply environments, power supply pins (VDD, GND)
can be decoupled with 100 nF capacitor to achieve
highest accuracy.
cases. The data is valid on the rising edge of SCK.
Figure 4 AH31 SPI readout sequence
(1) SPI mode 0,0 as defined in Motorola microcontroller datasheets
(2) See Application Note “Resolution Enhancement” for information on how to achieve resolutions of up to 12bit / 0.1%RH / 0.1°C.
(3) For best accuracy wait 60sec after powerup before the first measurement to allow the device to reach its operating temperature. If this is not
suitable for your application consult the Application Note "Low Power Measurements" for an alternative solution.
www.sensirion.com
September 2001 Advance Information
3/7
SHT11 Relative Humidity & Temperature Sensor System
See the application note “Low Power Measurements”
for information on how to achieve average power
consumptions of below 1.5µA with the use of the power
down mode.
2.3 Other Pins
2.3.1 Powerdown (PD)
While PD is high the device is powered down.
The powerdown sequence described below must be
observed.
2.3.3 Reset Sequence
The powerdown sequence described above will also
If not used this pin must be tied to GND
cause a reset to the device.
2.3.2 Powerdown Sequence
Clock Serial Number (CKS)
Clock CLK has to continue for at least 16 cycles after
the rising edge of PD. It can then be shut off to achieve
lowest powerdown consumption.
CKS is not used in normal operation and must be tied
to VDD locally. Voltage spikes relative to VDD on this
pin may cause a temporary loss of the calibration data.
After the falling edge of PD the device will initialize itself
for 1350 cycles (43ms @ 32kHz) of the main clock and
(1)
should not be accessed during that time.
Powerdown
mode
Wakeup and
Wait
Powerup mode
Measurement
PD
CLK
16 CLK
cycles
min. 1350 CLK
cycles
SCK
CS
Figure 5 Powerdown and Reset Sequence
(1) For best accuracy wait 60sec after powerup before the first measurement to allow the device to reach its operating temperature. If this is not
suitable for your application consult the application note "Low Power Measurements" for an alternative solution.
www.sensirion.com
September 2001 Advance Information
4/7
SHT11 Relative Humidity & Temperature Sensor System
3 Specifications AH31
3.1 Absolute Maximum Ratings
3.4 Reliability Tests
(1)
Ambient Storage Temperature:
-40°C to 90°C
Extensive test were performed in various environments.
Reflow soldering as described in “Soldering
Information” is allowed.
3.2 Operating Conditions
Test
Standard
(1)
Temperature Cycles
PRESSURE COOKER
Salt Spray
JESD22-A104-A
JESD22-A110-B
100
90
80
70
60
50
40
30
20
10
DIN-50021ss
Elevated Atmosphere
Top of Swiss mountain
Cellular Phone
JESD22-A101-B
-
-
-
-
Tab Water
Ethanol
-30 -20 -10
0
10 20 30 40 50 60 70 80 90 100
Ambient temperature in °C
Table 3 Qualification data (extract)
3.3 ESD (Electrostatic Discharge)
ESD immunity is qualified according to MIL STD 883E,
method 3015 (Human Body Model at 2kV)).
Please check www.sensirion.com for results and
additional information.
Latch-up immunity is provided at a force current of
100 mA with Tamb=80°C according to JEDEC 17.
(2)
3.5 Electrical Specifications
VDD=5V, Temperature=25°C unless otherwise noted
DC Characteristics(2)
Parameter
Conditions
Min.
3.3
Typ.
Max. Units
(3)
Power supply DC
5
5.5
V
Operating current
Powerdown current
PD=0 CLK=32kHz
PD=1 CLK=32kHz
PD=1 CLK=0kHz
600
800
µA
µA
µA
V
50
0.3
0.2
4.9
1
0.4
5
Low level output voltage
High level output voltage
Low level input voltage
High level input voltage
Input current
0
4.0
0
V
Negative going
Positive going
1.1
5
V
3.9
V
1
µA
µA
µA
(4)
Output peak current
active
4000
Tristated (floating)
10
Table 4 AH31 DC Characteristics
AC Characteristics(2)
Parameter
Conditions
Min.
Typ.
Max. Units
(5)
CLK frequency
30
40
32
50
60 kHz
CLK duty cycle
60
%
PD high time
16
CLK cycles
CLK cycles
First SPI access after reset or
1350
PD falling edge
Table 5 AH31 AC Characteristics (without SPI signals)
(1) Temperatures above 60°C with RH>60% will temporarily offset the RH signal by up to +3%RH. The sensor will slowly return to calibration
conditions but heating the device up to 90°C at <5%RH for 24h will repeal the effect of high RH, high temperature environments promptly.
(2) Parameters are periodically sampled and not 100% tested.
(3) VDD below 4.5V may affect the offset of the humidity / temperature signal by up to +/-1%RH, +/-0.5C.
(4) Continuous current drain on the output pin will heat up the device and may affect the temperature and humidity measurement.
(5) The temperature sensor will have an offset of –0.5°C / 10kHz at CLK frequencies above 32kHz.
www.sensirion.com
September 2001 Advance Information
5/7
SHT11 Relative Humidity & Temperature Sensor System
SPI I/O Characteristics
Symbo Parameter
l
Conditions
Min.
Typ.
Max. Units
FSCK
TRFO
SCK frequency
10 MHz
20 ns
200 ns
ns
MISO rise/fall time
Output load 5 pF
3.5
10
Output load 100 pF
30
100
100
2
40
TCLH
TCLL
TCSS
SCK high time
SCK low time
/CS setup time
ns
CLK
cycles
ns
TC
MISO valid from SCK low
Output hold time
50
10
THO
0
3
ns
TR/TF SCK rise/fall time
200 ns
CLK
TCSD
CS disable time
Between two accesses to
the same device
512
cycles
Table 6 AH31 SPI Signals Characteristics
Figure 6 AH31 SPI Timing Diagram
4 Physical Dimensions and Mounting Information
Solder balls
Sensor
2
.
5
4
overall height (incl. balls)= 3.5mm
All measurements in mm
Ø 0.7mm
openings
8
5
4
6
7
3
.
3
5
.
0
8
3
2
1
1
0
.
2
Pin 1
8
Figure 7 AH31 Mounting Information, bottom and side view.
The AH31 sensmitter housing consists of a Liquid Crystal Polymer (LCP) cap on a standard FR4 substrate.
4.1 Mounting Recommendations
Relative humidity measurements are very sensitive to
temperature variations. It is essential to keep the
sensmitter at the same temperature as the air of which
the humidity is to be measured.
The mounting location should be carefully chosen to
avoid warm up of the sensmitter due to heat conduction
(e.g. through the PCB) or radiation (Sunlight, hot
electronic components).
www.sensirion.com
September 2001 Advance Information
6/7
SHT11 Relative Humidity & Temperature Sensor System
4.2 Delivery Conditions
The AH31 will be delivered in standard IC tubes by max. 60 pieces per tube.
IC Tube
AH31
AH31
AH31
AH31
AH31
AH31
AH31
AH31
AH31
AH31
AH31
AH31
AH31
5 Soldering Information
The AH 31 can be soldered using standard reflow soldering procedure. For information see application note “Soldering
Procedure”
6 IMPORTANT NOTICES
The warranty for each SENSIRION AG product comes
in the form of a written warranty which governs sale
and use of such product. Such warranty is contained in
the printed terms and conditions under which such
product is sold, or in a separate written warranty
supplied with the product. Please refer to such written
warranty with respect to its applicability to certain
applications of such product.
specifications and/or information in this document and
to improve reliability, functions and design.
SENSIRION AG assumes no responsibility or liability
for any use of SENSIRION AH31 product. Application
examples and alternative uses of the SENSIRION
AH31 are for illustration purposes only and
SENSIRION AG makes no representation or warranty
that such applications shall be suitable for the use
specified.
These products may be subject to restrictions on use.
Please contact SENSIRION AG for a list of the current
additional restrictions on these products. By purchasing
these products, the purchaser of these products agrees
to comply with such restrictions. Please contact
SENSIRION AG for clarification of any restrictions
described herein.
SPI™ is a trademark of Motorola.
Copyright 2000, SENSIRION AG. All rights reserved.
7 Caution
The inherent design of this component causes it to be
sensitive to electrostatic discharge (ESD). To prevent
ESD-induced damage and/or degradation, take normal
ESD precautions when handling this product.
SENSIRION AG reserves the right, without further
notice, to change the SENSIRION AH31 Relative
Humidity and Temperature Sensor product
Headquarters and Sales Office
SENSIRION AG
Eggbühlstr. 14
P.O. Box
Phone: + 41 (0)1 306 40 00
Fax:
+ 41 (0)1 306 40 30
e-mail: info@sensirion.com
http://www.sensirion.com/
CH-8052 Zürich
Switzerland
www.sensirion.com
September 2001 Advance Information
7/7
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