Sensor Chips Information
Last revised: December 5, 2024
Reviewed by: Scott Orlosky, consulting engineer
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
- CO2 Sensor Chip (gas & Liquid Sensors)
- 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:
- 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 61508-1.
Sensor Chips FAQs
How are sensor chips integrated into electronic circuits?
Integrating sensor chips into electronic circuits involves several steps and considerations.
Selection of Sensor Chips
Choose the appropriate sensor chip based on the physical parameter to be measured (e.g., temperature, light intensity, magnetic field, mechanical pressure).
Consider parameters like sensitivity, accuracy, response time, physical environment and power consumption.
Sensor Interface Chips
Data Collection and Transmission: Sensor interface chips are used to collect data from the sensor and send it to a computer or other suitable device for processing.
Integration with VLSI Technology
Some sensors can be made on VLSI (Very Large Scale Integration) chips, although many are not compatible with VLSI technology.
On-chip sensors are often by-products of the VLSI fabrication process and may require sophisticated electronic means to compensate for performance limitations, leading to the creation of on-chip smart sensors.
Packaging and Assembly
Sensor chips are available in various integrated circuit (IC) package types, which need to be selected based on the application requirements and compatibility with the rest of the electronic circuit.
Applications
Use Cases: Sensor chips are used in a variety of applications including battery-operated devices, industrial smoke detectors, exercise equipment, security systems, home appliances, medical equipment, computers, and tablets.
Power Management
Ensure that the sensor chip's power consumption is compatible with the overall power budget of the electronic circuit. For example, some sensor chips can perform over 140,000 floating point operations per second at an average current consumption of ~200 µAmps at 1.8V.
Testing and Calibration
After integration, the sensor chip and the electronic circuit need to be tested to ensure they meet the desired performance specifications.
Calibration may be necessary to ensure the accuracy and reliability of the sensor readings. One form of calibration is an on-board look-up table.
What are on-chip sensors and how are they made?
On-chip sensors are often by-products of the VLSI fabrication process and may require sophisticated electronic means to compensate for performance limitations. Examples include thermal sensors made using the thermal properties of on-chip devices like bipolar transistors, and optical sensors made using the optical properties of pn junctions and transistors.
What are some challenges in integrating sensor chips with VLSI technology?
Many sensors are not compatible with VLSI technology. However, some sensors can be made on VLSI chips, such as thermal sensors using bipolar transistors and optical sensors using pn junctions. The performance of these on-chip sensors may not always be satisfactory and may require compensation through sophisticated electronic means.
How do sensor interface chips work?
Sensor interface chips collect data from sensors and send it to a computer or other suitable device for processing.
What are the common applications of magnetic sensor chips?
Magnetic sensor chips have a wide range of applications due to their ability to detect and measure magnetic fields. Here are some common applications:
Automotive Industry
Position sensing: Used in detecting the position of various components such as throttle position, pedal position, and gear position.
Speed sensing: Employed in anti-lock braking systems (ABS) and electronic stability control (ESC) systems to measure wheel speed.
Current sensing: Utilized in battery management systems to monitor the current flow.
Consumer Electronics
Compass in smartphones: Integrated into smartphones to provide orientation and navigation capabilities.
Gaming controllers: Used in gaming controllers for motion detection and enhanced user interaction.
Industrial Applications
Robotics: Employed in robotic systems for position and orientation sensing.
Automation systems: Used in automated systems for detecting the position of moving parts and ensuring precise control.
Medical Devices
Magnetic resonance imaging (MRI): Utilized in MRI machines to detect magnetic fields and create detailed images of the body's internal structures.
Implantable devices: Used in certain implantable medical devices to monitor and control various physiological parameters.
Aerospace and Defense
Navigation systems: Integrated into navigation systems for aircraft and spacecraft to provide accurate heading information.
Weapon systems: Used in targeting and guidance systems for precision control.
Energy Sector
Smart meters: Employed in smart meters to measure electrical current and provide accurate energy consumption data.
Wind turbines: Used in wind turbines to monitor the position and speed of the rotor blades.
These applications leverage the ability of magnetic sensor chips to provide accurate and reliable measurements of magnetic fields, which are critical for the proper functioning of various systems and devices.
Sensor Chips Media Gallery
References
GlobalSpec—Mixed Analog-Digital VLSI Devices and Technology
GlobalSpec—Sensor Interface Chips
Electronics360—PNI’s SENtral-A2 Combos Tiny and Low Power for Wearables
Image Credits:
Innovative Sensor Technology IST USA Division | All Sensors Corp.
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