Advantages and Applications of MFS 02 Fast Flow Sensor

Especially for fast flow measurements and wire bonding assembly, the Flow Sensor MFS 02 was developed. Due to a membrane system the thermal mass is reduced to the minimum. Very fast response time and low power consumption are resulting from this little thermal mass.

The membrane is just a few microns thick and is carried by a glass substrate. Therefore the system is robust and the device can be handled easily.

Advantages of MFS 02 Flow Sensor

The advantages of MFS 02 Flow Sensor include:

• Fast response time
• Small mass flow rates
• Detection of flow direction
• Low power consumption
• Small thermal mass
• Robust design
• Best price-performance ratio

Applications of MFS 02 Flow Sensor

• Medical devices
• Home spirometers
• Differential pressure sensors
• Mikrofluidic (gas)

MEMS-Manufacturing Process –F O T U R A N

Photo-Structuring

Final Sensor Element

MEMS-Manufacturing Process –Sensor Structures

• Photo structured glass substrate with membrane -polymere dot
• Spin coating prozess
• Sputtering thin film platinum
• Photolithographic mask process
• Ion based etching process
• RTD-structure passivation

Sensor Application –Chip Layouts and Circuits

• Different resistor arrangements and values depending on flow application
• Customized sensors possible because of inexpensive mask processes

Simple resistive structure for using in CTA -mode

Using as full bridge with Constant voltage or current supply Flow direction sensitive

Using as full bridge in a CTA; Flow direction sensitive

Sensor Application –Thermal Sensor Properties

Simple full bridge calorimeter mode Sensor supply 3mA and about 2,5 volts Flow rate 0,00 mlN/min

Simple full bridge calorimeter mode Sensor supply 3mA and about 2,5 volts Flow rate 200 mlN/min

Full bridge calorimeter mode and CTA biasing Sensor supply 4mA and about 3,5 volts Flow rate 600 mlN/min

Sensor Application –Measuring Properties

• Unamplified nominal sensitivity 3mV/ mlNmin^-1 In zero cross point
• Physical flow range enlargement by full bridge mode with CTA biasing
• No cool down effect of heater with CTA biasing.
• Heating power 10mW to 50mW
• Stable zero cross point; independent on any drift effects like contamination.

High flow CTA mode-range

Sensor Application –Assembly Possibilities

• Easy to use and robust sensor construction
• PCB integration by mounting in a cavity or hole
• Connecting by wire bonding or soldering
• Backsite mounting of flow channel

• Sensor mounted in a separate flow channel
• wire bonded flow sensor for pcb connection
• Pick & place assembling of sensor possible
• Plug and play module by USB interface

Example with the wire bonding sensor type MFS02 together with an ASIC on a pcb.

This information has been sourced, reviewed and adapted from materials provided by Innovative Sensor Technology, USA Division.

For more information on this source, please visit Innovative Sensor Technology, USA Division.