AM62Ax Temperature and Power Environmental Stresstesting Results¶

The MitySOM-AM62Ax SOM (62A74-TX-DAD-RI) was placed in the MitySOM-AM62 Development Kit and loaded into the environmental chamber with the following configuration:

1. Industrial Temperature micro-SD used for boot media and reference filesystem
2. Industrial Temperature USB stick loaded into one of the USB 2.0 HUB positions
3. ETH0 port connected to an internal network at 1 Gbps link rates.
4. Micro-USB console port connected to external PC for console monitoring.
5. Attach passive heat sink ATS-52150G-C1-R0

Stress Test software was enabled on the MitySOM-AM62Ax to perform the following operations (continuously) during test:

1. Running the "memtest" application on 256 MB of DDR4 memory
2. Running nandtest continuously on the MitySOM-AM62 OSPI NOR partitions
3. Running stress-drive tests on a micro-SD card partition.
4. Running a stats collection script which gathers CPU temperature, power / current draw, and CPU utilization
5. Running iperf on eth0

The system was allowed to run while the environmental chamber ranged from -45C to 85C, including soaks at each end of the range.

The figures below show the temperature of the AM62Ax (die temperature as reported by the kernel software), the chamber, the computed temperature rise, and the power consumed by the SOM.

Idle testing with Passive Heatsink Attatchment¶

In this case, the ATS-52150G-C1-R0 passive heatsink was attached and the system was booted to Linux and no additional software was run (beyond the data logging software) while the chamber was ramped from room temperature to +85C. From the figures, the power consumption of the SOM is much lower, and the unit was able to run at temperatures up to 85C ambient. From our test, we were able to achieve a average on-die temperature of 98.65 C with an average power consumption of 1.84 W at 85 C chamber temp.

CPU Max Frequency & # of Active Cores vs. CPU Temperature¶

Measurements were taken while running a minimal stresstest with only the CPU and DSP being performed on while using passive heat sink ATS-52150G-C1-R0. Each measurement is the mean of collected periodic samples over a 1 hour soak period at the specified ambient temperature.

The following tests were conducted using a 62A74-TX-DAD-RI SOM

Ambient = 85 C

CPU Max Frequency (kHz)	# of CPU Cores	SOM CPU Temp (°C)	SOM Power Measurement (W)
1250000	4	103.07	2.68
1250000	1	101.31	2.41
800000	4	102.03	2.52
800000	1	100.66	2.29
200000	4	99.82	2.17
200000	1	98.98	2.03

High-Temperature Enclosure Stress Testing¶

To evaluate hardware stability beyond normal operating conditions, a MitySOM-AM62Ax development kit was placed within an unventilated secondary enclosure inside an environmental chamber. This setup mimics zero-airflow system environments where internal ambient heat builds up rapidly.

Extreme Thermal Test Configuration¶

To allow the system to operate at elevated temperatures near silicon limits without hardware self-protection intervention, the following software overrides were applied:

• Device Tree Override:
  • Removed critical software thermal trips to prevent kernel thermal shutoff.
• PMIC Safety Masking:
  • Disabled hardware thermal shutoff registers on the TPS65219 PMIC via an I2C command

Benchmark Test Setup¶

• SOM Variant: AM62Ax Industrial Grade (-40C to 85C rated) SOM, specifically used 62A74-TX-DAD-RI
• CPU Frequency: 1.25 GHz across all 4 cores
• Cooling: Passive Heatsink FIT0982 was used with 0.3mm thick thermal padding to adhere in the center onto the SOC on the SOM
• Active Workloads:
  • Running the "memtest" application on 256 MB of DDR4 memory
  • Running stress-drive tests on a micro-SD card partition
  • Running a stats collection script which gathers CPU temperature, power / current draw, and CPU utilization
  • Running iperf on eth0
  • Running the DSP core
  • Running a test pattern on a 1920x1080p monitor connected to the HDMI port
• Chamber Profile: Thermal soaks were executed at 75C and 85C ambient for 8hr each

Summary of Thermal and Power Limits¶

The AM62Ax was able to reach a maximum on-die temperature of 119.55 C and a maximum power usage of 3.16 W at a chamber temperature of 85C with air space temperature within the enclosed box reaching 92C. The SOM was still operational at this temperature, maintained iperf data rates of ~750-800 Mbps, and experienced no memory test failures.

Despite being operational at this temperature for an 8hr soak, it is still NOT recommended to override the SOM's thermal regulations to reach these thermal temperatures on Industrial grade components as these high temperatures could degrade the SOC and SOM lifespan and cause unexpected behavior and system instability.

The figures below show the temperature of the AM62Ax (die temperature as reported by the kernel software), the chamber, the compute temperature rise, and the power consumer by the SOM.