Behind the Largest Family of Automotive Multi-Channel Temperature Sensors


Microchip has launched ten new multi-channel, automotive-qualified remote temperature sensors accurate to within 2.5°C up to 125°C. 

 

The MCP998x targets automotive applications. 

 

Microchip says the goal of this new portfolio is to offer customers more variety in a product category that has historically had few options.

 
The New Family Scores AEC-Q100 Qualification

The individual devices in the newly released MCP998x family are all AEC-Q100 Grade-1 qualified for automotive applications. AEC-Q100 is a set of qualification test sequences that determine whether a component is suitable for use in automotive conditions.

There are two grades: Grade 0 and Grade 1. Grade 0 indicates that parts are qualified to operate at a temperature range of -40°C to 150°C, while Grade 1 indicates they are qualified to operate at a temperature range of -40°C to 125°C. This qualification contrasts commercial qualification, which generally only guarantees performance at room temperature. The MPCP998x devices are all two-wire sensors, interfaceable using both I2C and SMBUS, a communication protocol based on the former.

 

Block diagram of MCP9982/3/4 device family

Block diagram of MCP9982/3/4 device family. 
 

Different devices within the family (datasheet linked) also come in different no-lead packages. The MCP9982, MCP9933, MCP9982D, and MCP9933D, for example, are available in a 2 mm x 2 mm WDFN (wide dual flat no-lead) MSOP-8 package. The MCP9983, MCP9984, MCP9985, MCP9983D, MCP9984D, and MCP9985D are available in 2 mm x 2.5 mm VDFN (very thin dual flat no-lead) packaging. Dual flat no-lead packaging has higher electrical performance than leaded packages due to less wiring and, consequently, experiences less inductance. DFN packages also have good thermal dissipation, which is particularly suitable for a temperature sensor.

Temperature sensors must have efficient temperature dissipation so the device can maintain sufficient accuracy. According to the datasheet, the MCP998x family has an external temperature sensing accuracy of within 1°C up to 85°C ambient temperature and an accuracy within 2.5°C up to 125°C. The temperature resolution, or the granularity with which a device can sense a particular temperature, is 0.125°. 

 

Precision and Security Safeguard Automotive Design 

Microchip equipped its new lineup with ALERT/THERM pins. Once the temperature reading exceeds the upper limit or drops below the lower limit, the ALERT/THERM pin will be asserted.

Some devices in the lineup, such as the MCP9984D, also have a SYS_SHDN pin. This asserts a non-maskable shutdown signal if the temperature exceeds a programmable value referred to as a THERM limit. If this occurs, the SYS_SHDN pin will stay asserted until the temperature returns to the THERM limit minus 10.

 

Example of a system design use case for MCP998x temperature sensor

Example of a system design use case for the MCP998x temperature sensor.

 

This pin is non-maskable, a key security feature that disables all hardware safeguards if malicious software tries to make the system overheat. Some devices in the lineup also include anti-parallel diode connections. These provide a path for electric discharge that is isolated from the rest of the circuit. 

 

Now More Temperature-Sensing Options

The MCP998x is not without competition. Texas Instruments has long been a manufacturer of automotive-grade, two-wire temperature sensors. The TMP107-Q1 (datasheet linked), for example, is AEC-Q100 qualified and offers a higher temperature sensing accuracy of 0.4°C. However, automotive customers may find the multi-channel capabilities of the extensive MCP998x lineup compelling for a wider variety of use cases.

 

 

All images used courtesy of Microchip.



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