Description

Sensor chips are dies incorporating semiconductor circuit elements that are used to convert changes to some physical parameter to an electrical signal. Like other semiconductors, a sensor chip can be flexible, and can be manufactured as a signal conditioning chip, a stand-alone transducer, or a combination.

Types

There are several kinds of sensor chips:

• Biometric sensor chips
• Inertial sensor chips
• Light sensor chips
• Magnetic sensor chips
• Pressure sensor chips
• Temperature sensor chips
• Gas and liquid pressure
• Load cells (force sensors)
• Chemical (pH, oxygen, carbon dioxide)
• Mechanical (acceleration, position, pressure, knock, rotation)
• Optical (single-chip cameras, edge detectors, and image pattern recognizers)
• Medical (protein interactions) 

Performance Specifications

Performance specifications for pressure sensor chips include:

• Pressure range
• Supply voltage
• Impedance
• Impedance temperature coefficient
• Bandwidth
• Accuracy
• Long term stability

Performance specifications for temperature sensor chips include:

• Temperature range
• Supply voltage
• Impedance
• Impedance temperature coefficient
• Bandwidth
• Accuracy

Other sensor chips have specifications unique to the application. For example, single-chip cameras have array resolution, pixel pitch, fill factor, array size, peak responsivity, sensitivity, and dynamic range, among others.

Integrated Circuit (IC) Package Types

Sensor chips have several integrated circuit (IC) package types:

• SC-170, which is used in handheld devices such as cellular phones and personal digital assistants (PDAs)
• Small outline transistor (SOT) packages like SOT23 and SOT123
• Small outline (SO) packages like SO-8 and SO-16
• Transistor outline packages such as TO-8
• Bare die
• Quarter size outline package (QSOP)

Sensor chips can interface with several hardware busses, including the:

• System management bus (SMBus)
• Industry standard architecture (ISA) bus
• I2C bus
• Actuator sensor interface (also called AS-I or ASi) 

Standards

Sensor chips that meet the requirements of Institute of Electrical and Electronic Engineers (IEEE) Standard 1451 can transmit electronic data to a data acquisition system. Sensor chips used for machinery safety/emergency stop applications can provide safety support up to Safety Integrity Level (SIL) 3 according to International Electrotechnical Commission (IEC) standard IEC 61508.

References

Image Credits:

Innovative Sensor Technology IST USA Division | All Sensors Corp.