Thermocouples are an affordable, yet precise way to measure remote temperatures. The MCP9604 is a four-channel thermocouple conditioning integrated circuit that provides measurements via the industry-standard I2C bus.

Converting thermocouple analog information to readily processable digital temperature data requires computation. The MCP9604 family provides a comfortable external processor. As shown in the figure below, the host microcontroller uses the I2C bus to configure the chip, which then provides a stream of digital temperature data.

Alerts and Sensor Monitoring Come for Free

The introduction of the 4/20 mA industrial signaling system was driven by the need to detect when the sensor connection is broken. In the MCP9604, Microchip integrates both open-circuit and short-circuit detection. If this chip feature is enabled, the chip issues warnings to the microcontroller via an alert pin. The MCU\'s interrupt logic can be used to monitor these alerts without polling in the embedded software.

The MCP9604 provides dedicated threshold alerting logic. This means that the chip permanently monitors the temperature values reported by the thermocouples and can assert its alert output if an abnormal condition is detected.

Finally, the part achieves accuracies of +/-0 25°C in regular operation. The actual results depend on the type of thermocouple used. Further information on the available accuracy bracket is shown below.

Single and Four-Channel Versions Available

The MCP9604 stems from a legacy of units. The whole family tree, available in a variety of housings, is shown in the figure below. The presence of an address pin ensures that multiple instances of the component can coexist on the I2C bus without address collisions.

Purchasing the SKU MCP9604-E/3YW, for example, yields a four-channel unit in a VFLGA package with extended temperature capability. If a single-channel version is preferable, SKU MCP96RL01-E/MX provides an MQFN version with an extended temperature range. SKUs such as MCP9604T-E/3YW offer tape-and-reel packaging well-suited to large-scale PCB assembly operations. In all cases, microcontroller integration is simple. The designer needs to ensure that pull-up resistors are provided on both the SDA and SCL lines. After that, temperature measurement can commence immediately.

Conclusion

If a design requires temperature measurement with analog thermocouples, the MCP9604 is an ideal choice. Thanks to its high-accuracy conversion logic and various alerting features, circuit designers can rest assured that their temperature monitoring system will handle the most challenging environmental conditions.