ASAIR AHT10 User manual

AHT10 Technical Manual ASAIR®
Temperature and humidity sensor
•Fully calibrated
•Digital output, I2Cinterface
•Excellent long-term stability
•SMD package reflow solderable
•Fast response and strong anti-interference ability
Application range
HVAC, dehumidifiers, testing and testing equipment, consumer goods, automobiles, automatic control, data logger,
weather home appliances, humidity regulation, medical and other related temperature and humidity detection and
control.
1- ADR
2- SDA
3- SCL
4- VDD
5- GND
6- NC
Figure 1: AHT10 sensor package diagram (unit:mm tolerance: 0.1mm)
Product overview
AHT10,the new generation of temperature and humidity
sensors sets a new standard in size and intelligence: it is
embedded for reflow soldering
The dual-row flat leadless SMD package has
a4x5mm bottom and a height of 1.6mm. The sensor
outputs a calibrated digital signal in standard I2Cformat.
The AHT10 is equipped with a newly designed
ASIC- specific chip, an improved MEMS semiconductor
capacitive humidity sensing element and a standard on-
chip temperature sensing element. Its performance has
been greatly improved beyond the reliability level of the
previous generation of sensors. The first generation of
temperature and humidity sensors have been improved to
make them more stable in harsh environments.
Each sensor is calibrated and tested with a product
lot number printed on the surface of the
product. Thanks to improved and miniaturized
sensors, it is more cost-effective and ultimately all
equipment will benefit from cutting-edge energy-
saving operating modes.
6
2
5
3
4
1
0.8
0.8
4.0
5.0
1.27
1.0
AHT10
1.6
2.7
ASAIR
XXXXXX
®

Sensor performance
Relative humidity
table 1 humidity characteristics table △RH(%RH)
0 10 20 30 40 50 60 70 80 90 100
Figure 2The maximum error of relative humidity at 25 °C
1. This accuracy is the test accuracy of the sensor at a
factory voltage of 3.3V at 25 °C . This value does not
include hysteresis and nonlinearity and only applies
to Non-condensing conditions. 2 The time required to
achieve a first-order response of 63% at 25 ° C and 1 m /
sairflow.
2. Normal operating range: 0-80% RH, beyond this range,
sensor readings will be biased (drift <3%
RH after 200 hours at 90% RH humidity ).The scope of
work is further limited to -40–80 °C .
3. If there are volatile solvents, irritating tapes, adhesives,
and packaging materials around the sensor,the
readings may be high. Please refer to the relevant
documents for detailed instructions.
4. The minimum and maximum values of supply current and power are based
on VDD = 3.3V and T < 60 ° C conditions. The average is the value measured
once every two seconds.
Temperature
table 3 temperature characteristics table
-40 -20 0 20 40 60 80
Figure 3Typical temperature error and maximum error
5. The response time depends on the thermal conductivity of the sensor
substrate.
6. Contact surface means The metal layer on the PCB where the SMD pads
are soldered.
7. Solder mask The top layer of the PCB covers the insulating layer on the
connecting line.
8. The type of solder is related to the size of the internal particles of the
solder. Type 3 sizes range from 25 –45 μm powder.
9. 75% RH can be easily saturated NaCl is generated.
parameter
condtn
min
typ
max
unit
Resolution
typical
0.024
%RH
Accuracy
typical
±2
%RH
maximum
See Figure 2
%RH
Repeatability
±0.1
%RH
Hysteresis
±1
%RH
Nonlinear
<0.1
%RH
Response
t 63%
8
S
scope
extended
0
100
%RH
Drift
normal
<0.5
%RH/yr
parameter
condtn
min
typ
max
unit
Resolution
typical
0.01
℃
Accuracy
typical
±0.3
℃
maximum
See Figure 3
℃
Repeatability
±0.1
℃
Hysteresis
±0.1
℃
Response
t 63%
5
30
S
scope
extended3
-40
85
℃
drift
<0.04
℃/yr
±0
±2
±4
±6
±8
±10
最大值
典型值
±0.0
±0.5
±1.0
±1.5
±2.0
最大值
典型值

electrical characteristics
parameter
condition
min
typ
max
unit
Supply voltage
typical
1.8
3.3
3.6
V
Supply
current,IDD
Sleep
-
0.25
µA
measuring
23
µA
Power
Sleep
-
0.9
µW
measuring
0.07
mW
average
-
3.3
-
µW
communication
Two-wire digital
interface ,standard I2Cprotocol
Table 2Electrical characteristics
packaging information
Sensor model
package
Quantity
AHT10
Tape and
reel
packaging
4000PCS/ volume
Table 4package information.

AHT10 User Guide
11 Expansion performance
1.1 Working conditions
The sensor has stable performance within the
recommended operating range, see Figure 4 . Long-
term exposure to conditions outside the normal range,
especially at humidity >80 %, may result in temporary
signal drift (drift after 60hours +3% RH ). When
returning to normal operating conditions, the sensor
will slowly self-recover to the calibration state. Refer
to Section 2.3, “Recovery Processing ”to speed up the
recovery process. Prolonged use under abnormal
conditions will accelerate the aging of the product.
-40 -20 0 20 40 60 80 100 (℃)
1.2 RH accuracy at different temperatures
The RH accuracy at 25 °C is defined in Figure 2 , and
the maximum humidity error in other temperature
segments is shown in Figure 5 .
Figure The maximum humidity error in the range of 0 0~80 °C , unit : (%RH) Please
note : The above error is the maximum error ( excluding hysteresis ) of the
reference instrument test with high precision dew point meter . The maximum
error of ± 3% RH typical range of error ± 2% RH, in other ranges, typically 1/2 of
the maximum error value.
1.3 Electrical characteristics
The power consumption given in Table 1 is
related to the temperature and supply voltage
VDD . About power estimation and see Figure 6
7 . Please pay attention to the picture 6 and The
curve in 7 is a typical natural characteristic and
there may be deviations.
Figure 6 VDD = 3.3V , typical supply current vs. temperature (sleep mode).
Please note that these data and display values are approximately ±25% deviation.
Figure 7 shows the relationship between typical supply current and supply
voltage at a temperature of 25 °C . Curve (sleep mode). Please note that
these data deviate from the displayed values. Can reach ±50% of the
displayed value . At 60 ° C , the coefficient is about 15
(Compared with Table 2 ).
150
120
90
60
30
温度
(
℃
)

2 Application information
2.1 Welding instructions
SMD 's I/O pads are made of copper leadframe
planar substrates, except that these pads are
exposed to the outside for mechanical and electrical
connections. When used, both the I/O pad and the
exposed pad need to be soldered to the PCB . To
prevent oxidation and optimize soldering, the solder
joints on the bottom of the sensor are plated with
Ni/Au.
On the PCB, I / O contact surface length should / O
pads package is larger than the AHT10 I 0.2mm, to
the portion on the inner side of the I / O pads to
match the shape, and the width of the lead width
ratio SMD pads of the package 1:1, see Figure 8 .
For stencil and solder mask design [7] It is
recommended to use a copper foil definition pad (
SMD ) with a solder mask opening larger than the
metal pad .
For the SMD pad, if the gap between the copper foil
pad and the solder resist layer is 60 μm - 75 μm , the
solder mask opening size should be larger than the
pad size 120 μm - 150 μm . The rounded portion of
the package pad is matched to the corresponding
round solder mask opening to ensure that there is
sufficient solder mask area (especially at the
corners) to prevent solder from intersecting. Each
pad must have its own solder mask opening to form
a solder mask network around the adjacent pads.
Figure 8 recommends the AHT10 PCB design dimensions (unit: mm), peripheral
The dotted line is the outer dimensions of the SMD package.
For solder printing, it is recommended to use a laser-
cut stainless-steel mesh with an electronically
polished trapezoidal wall. The recommended mesh
thickness is 0.125mm . The stencil size for the pad
portion must be 0.1 mm longer than the PCB pad .
And placed at a distance of 0.1mm from the center of
the package . The stencil of the exposed pad is
covered
70%-90% of the pad area —that is, 1.4mmx2.3mm at
the center of the heat sink area . Due to the low
placement height of SMD , it is recommended to use
no-clean type 3 solder. and purify with nitrogen
during reflow.
Figure 9 JEDEC standard welding process diagram, Tp <= 260 ° C, tp < 30 sec ,
lead-free soldering Pick up. TL<220°C, tl<150sec , the rate of temperature rise
and fall during welding Should be <5 ° C / sec .
The AHT10 can be soldered using a standard reflow
oven . The sensor is fully compliant with the IPC/JEDEC
J-STD-020D soldering standard. The contact time
should be less than 40 seconds at temperatures up to
260 °C ( see Figure 9) ; the ultimate soldering
temperature that the sensor can withstand is 260 °C .
Note: After reflow soldering, the sensor should be
stored in a >75% RH environment for at least 12 hours
to ensure rehydration of the polymer. Failure to do so
will cause the sensor reading to drift. It is also possible
to place the sensor in a natural environment ( >40%
RH ) for more than 5 days to rehydrate it. Use low
temperature reflow soldering
(Example : 180 ° C) can reduce hydration time.
Do not flush the board after soldering. Therefore, customers are advised
to use " no-clean " solder paste. If the sensor is used in corrosive gases
or if condensed water is produced (eg, in a high-humidity environment),
both the lead pad and the PCB need to be sealed (eg, using a conformal
coating) to avoid poor contact or short circuit.
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