General Description

CH4 sensor is a miniature metal oxide semiconductor gas    sensor based on MEMS micro hotplate technology for detection a wide rang of CH4  gas in air. Sensor production combined with silicon substrate  MEMS technology, thin film technology, thick film  technology  and  ceramic  packaging  technology.  The  gas sensitive  layer  is  deposited  at  the  top  of  the  hotplate  and interdigitated electrodes, resulting in a conductivity dependent on the concentration of harmful gases.

Features:

High sensitivity to CH4 ( 50~15000ppm )

Quick response (~10Sec.)

Very low power consumption ( ~60mW )  

Small size  ( 3.8mm × 3.8mm × 1.5mm )

Long operating life ( ~10 Years )

Reflow soldering

Applications:

Natural gas leakage alarm

Portable detector

IoT, wearable devices, smart home

Performance parameter

Package outline

Pin connections

Pin    Function

1       Heater Electrode 1

2       NA

3       Sensor Electrode 1

4       NA

5       Heater Electrode 2

6       NA

7       Sensor Electrode 2

8       NA

Heater Circuit

Sensor Circuit

Remarks

1,  R0  is tested under standard environmental conditions, i.e., in a clean air with a temperature of 25 ± 3 C and a humidity of 50 ± 10%.

2,  S1k  is defined as R0/Rg , Rg  is the sensor resistance in the air of  1000 ppm CH4 concentration, 25 ± 3 C, 50 ± 10%.

3, The response time and recovery time is defined as the time interval from the contact the specified gas concentration to the 70% of the stable resistance variation.

4,   RH  is measured in the condition of heating power 60mW , and will change with heating power changes. This feature can   be   used  to  do  temperature  compensation.   Under standard  conditions,  the  heating  power  PH  should  be  set within 59~61mW . Excessive heating power will shorten the service life of the gas sensor, even damage the sensor.

5,  VS   is  the  voltage  applied  to  the  sensor  electrodes,  and should be kept ≤ 5.5V in working condition. Too high voltage will  shorten  the  service  life  of  the  gas  sensor  and  even damage the gas sensor.

6,  Ps is the power applied to the sensor electrodes, and should not be greater than 1mW .

Operating Environment

Typical measurement circuit

Remarks

VH:  5.0VDC ± 2%

Vc:   5.0VDC ± 2%

R1: 82Q. The heating power can be adjusted by R1. In order to obtain ideal gas sensing characteristics, the heating power of the gas sensor under standard    ambient    conditions should   be   within   the   target range.

RL : 10~50 kQ     RL  ≥5 kQ to avoid the gas sensor damage.

The  sensor  has  no  polarity. Pin 1 and 5 are interchangeable, and Pin 3  and 7 are also interchangeable.

In   order   to   maximize   the performance advantages of the gas sensor,  the temperature compensation of the heating circuit can be carried out. Please contact us for more detailed information.

Recommended pad size

(Unit: mm)

Sensitivity characteristics

The figure below shows a typical gas sensor sensitivity characteristic curve. The Y-axis shows the ratio  Rg/R0 . The X-axis shows the test gas concentration. where Rg  is the resistance value of the  gas  sensor  in various  concentrations  of gas.

Please read the following terms carefully to avoid product data errors and prevent product damage.

1.  The  gas  sensor  must  be  reflow  soldering  in neutral   atmosphere.   The   welding   furnace should  have  sufficient  flow  of  clean  air  to maintain    the    air    clean.    The    maximum temperature   is   260 C .   Manual   soldering conditions are  recommended for a  maximum temperature  of  350  C for  5  seconds.  it  is recommended that it should be aged for more than  4  hours  to  eliminate  the  influence  of welding process on the gas sensor.

2.  The vacuum adsorption hole should be in the non  porous  area  of  the  sensor  upper  cover during SMT process. Select appropriate nozzle size and SMT parameters to avoid the sensor damage.

3.  Products   should   not   be   exposed   to   high concentrations of organic solvent vapor, silicone vapor,  in  order  to  prevent  sensitive  material poisoning.

4.  The  product  should  be  placed  in  the  filter protected space to prevent water and dust. If necessary, the installation direction can be used to prevent dust deposition.

5.  The   sensor   resistance   will   experience   a continuous increase after power on. The time span of this  process  depends  on the sensor heat  history  and  storage  environment.  The longer time is needed when off time is long. It is recommended to preheat at least 60 min. to get a reliable results.

6.  It  is  recommended  to  use  ESD  protection equipment when handling the products.

7.  It  is  recommended to  use  our filter  cover to eliminate the interference of alcohol and other VOCs gases on CH4 test.

Temperature and humidity dependence

The figure below show a typical characteristic curve    of    gas    sensor    is    influenced    by temperature  and  humidity.  The  Y-axis  shows the ratio Ra/R0 . The X-axis shows the working temperature. Where Ra  is the resistance value of the gas sensor  under various temperatures and humidity in the clean air.

Package

Tape and reel. (1000 pcs). Other packaging methods can   also   be   provided   according   to   customer requirements.

Environmental Protection

This product conforms to the current RoHS directive and can pass REACH certification. The product does not contain environmentally restricted chemicals.