Operative temperature range

VPU temperature range

The Robotics Vision Core 2 is rated for industrial use and has operating temperature of -40°C to 105°C, while other components have a higher temperature range.

General use case

Max temperature

In the general use case at a 25°C ambient, the chip running at full power (i.e. worst-case heat generation) resides at around 70°C maximum, which sets the thermal margin to a minimum of 35°C.

Since devices generate about 45°C in worst-case, this means the maximum ambient temperature should theoretically be 60°C (105°C-45°C=60°C).

OAK-D-Lite max temperature

As we wanted to make OAK-D-Lite as small as possible, we had to use a smaller heatsink. This means the maximum ambient temperature is about 40°C.

Test	Ambient [°C]	VPU [°C]	HS-CPU [°C]	HS [°C]
Test 1	30	87	71.5	67
Test 2	35	94	77	73
Test 3	40	100	88	78
Test 4	50	/	/	/
Test 5	50	112	95	90

Legend:

• Ambient temperature means the temperature of the air around the device

• VPU is the temperature of the Robotics Vision Core 2 (as reported by depthai)

• HS-CPU is the temperature of the enclosure where VPU is located

• HS is the temperature of the enclosure on the opposite side of the VPU

Tests 1-4 were running all 3 cameras at 30FPS, stereo depth, NN (mobilenet), and video encoding, so the maximum workload possible. As test 4 resulted in a crash of the device (at 125°C VPU temperature), test 5 was done without video encoding (only NN, stereo depth, and 3 cameras at 30FPS).

Min temperature

While an OAK camera would work below 0°C, a valid concern here is the condensation on the components with cycling the temperature - if the device isn’t waterproof. Worst case would be turning the cameras on and completely off several times week or even a day. This would cause condensation on the components and because of that, the stress on components would be bigger. Solution would be to spray PCBAs with a conformal coating to protect the components against humidity.

Pro versions (OAK-D Pro, OAK-D Pro PoE) have on-board IR laser dot projector that has an operating temperature range of 10°C - 60°C (abolute limit 0°C - 80°C). If you would like to use Pro devices below 0°C, we would suggest to first run the device (without projector) for a few minutes so the device heats up, which would also heat up the laser projector, hopefully above 10°C.

CCM heating

CCM (Compact Camera Module) are the modules that are integrated into the OAK cameras. OAK-D has 3 CCMs, 2x for stereo pair, and in the middle is the RGB camera. CCMs themselves have different operating ranges and also some have lower thermal noise than others (eg. on OAK Lite cameras, those CCMs have worse thermal noise).

We have done some quick testing on CCM heating with different sensors; IMX582, IMX214, OV9282, IMX378.

Sensor	Max temp [°C]	Temp diff [°C]
IMX582	64°C	30°C
IMX214	62°C	29°C
OV9282	50°C	13°C
IMX378	46°C	12°C

Temp diff is the difference between the ambient temperature and the temperature of the CCM.

Command used for testing

We have tested thermals of our devices with max load, and you can achieve that by using the depthai_demo: python3 depthai_demo.py -sub -lrc -rgbr 2160 --report cpu -enc color -encout /dev/null

This command has the maximum power consumption, therefore the devices have the highest heat output.

Note the framerate of the RGB camera is set to 30 (-rgbf 30). If it would be set any higher, it would be bottlenecked by the neural network.

Results of our tests

All devices were tested in an ambient temperature of 18°C to 20°C.

Test on the OAK-D-PCBA - rear thermal plate with black anodizing and Laird HD320 TIM:

• Heatsink max temperature: 43°C

• Die max temperature: 60°C

Test on the megaAI with the Tianmai 6.5W/K TIM for both the front heatsink and the MX. TMA-6518 (0.5mm) for the MX and the TMA-6500 (2mm) for the front were used. This test was with the BW machined heatsink.

• Heatsink max temperature: 61°C

• Die max temperature: 73°C

Tests for OAK-1:

1. 6535 back TIM only:

• Die max temperature: 78°C

• Rear heatsink max temperature: 62°C

• Front heatsink max temperature: 60°C

2. 6510 front + 6535 back TIM:

• Die max temperature: 70°C

• Rear heatsink max temperature: 59°C

• Front heatsink max temperature: 60°C

Test with T1 OAK-1 sample:

• Rear heatsink max temperature: 61°C

• Front heatsink max temperature: 63°C

• Die max temperature: 73°C

We have also tested the devices at the lowest ambient temperature of -25.1°C and they worked as expected.

Got questions?

Head over to Discussion Forum for technical support or any other questions you might have.