1.8V temperature sensing chip works with up to four external diodes

Working with on on-chip sensor, plus various combination of external diode-connected external transistors, the devices can pass temperature readings as well as rate-of-change readings to a host processor.

The family integrates from two to five remote channels, and some channels can accept two sensors over two wires by handling two transistors connected in anti-parallel.

Standard externals channels can be connected one of:

• a discrete diode-connected transistor
• a substrate diode
• a CPU/GPU thermal diode

Anti-parallel (APD) external channels can be connected one of the following:

• two separate discrete diode-connected transistors
• one substrate diode
• one CPU/GPU thermal diode

Each device has one on-die temperature sensor plus:

• EMC1812 – one standard external channel and an 8pin package (2 x 2mm WDFN)
• EMC1813 – one standard external channel and an 8pin package
• EMC1814 – one standard and one APD channel in a 10pin package (2.5 x 2mm VDFN)
• EMC1815 – two APD channels in a 10pin package
• EMC1833 – one APD channels in an 8pin package

Note: check this information as it is a little tricky to extract from the data sheet and errors might have crept in.

This device family introduces rate of change temperature measurement with associated alerts. This
provides a preemptive system alert and another protective measurement layer to catch and manage
variable system temperatures.

Resistance error correction is included to automatically compensate for the series resistance of external connections between chip and sensor, and beta compensation is included to allow for external sensor characteristics.

Each chip can sense over:

• 0 to +127.875°C in 0.125°C steps ±1°C accuracy with caveats.
• -64°C to +191°C (with binary output offset by 64°C) ±2°C accuracy over -40°C to 125°C with caveats

However, chip operating temperature with power applied can only spans -40°C to +125°C. “The extended range is used to measure temperature diodes with a large known offset (such as CPU/GPU processor diodes) where the diode temperature plus the offset would be equivalent to a temperature higher than +127°C,” said the firm.

Consumption varies from 75μA in standby to over 400μA depending on how many channels are being used.

Registers and voltage is compatible with the earlier 3.3V EMC14xx family, according to Microchip.

ADM00773 is an EMC1833 evaluation board which allows the user to view and modify registers, plot temperature from its three temperature channels and set alert temperatures associated with those channels.
Test points are included to monitor system voltages, the interface, and the alert channel via a meter or scope.
Power comes over the USB interface.