We had a pleasant chat with a bunch of Qualcomm that were kind enough to spend a good hour talking to Fudzilla about CPUs, GPUs as well SoC design in general, and the SoC in question was of course the company’s Snadragon.
Michelle Leyden Li – Senior director of marketing for Qualcomm CDMA Technologies, Tim Leland – Senior Director of GPU Product Management and Tavis Lanier Director of CPU Product Management spend a great deal of their time demystifying some of the facts about the Snapdragon.
One of the biggest things that we found out from this fruitful conversation was that something most of us know as TDP (Thermal design power) does not exactly apply to a SoC (system on chip) design such as the Snapdragon. While Intel measures TDP of a CPU alone, Qualcomm see the Thermal design power of the whole SoC not singling out the CPU.
Qualcomm feels that 45 degrees Celsius (113 degrees Fahrenheit) would be the maximum allowed temperature for SoCs such as the Snapdragon 600 or 800. Furthermore we learned that 2.5 to 3W would be the upper limit for Thermal dissipation of the whole SoC in a mobile phone, while the max thermal power of a tablet could go up to 5W.
The 2.5 to 3W envelope for phones and 5W for tablets is the inherent limitation of passively cooled mobile devices. Anything more than that would have to include an active cooling system, something that is next to impossible to implement in a mobile phone.
Snapdragon 600, the current flagship SoC from Qualcomm, has a 1.9GHz limitation while the soon to launch Snapdragon 800 has 2.3GHz limit, all in order to stay below the designed thermal power of 2.5W to 3 W for phones and 5W for tablets. Snapdragon 600 chips are already in some key devices such as the HTC One, Samsung Galaxy S4 as well as LG’s Optimus G Pro, while The Snapdragon 800 is expected in a month or two if not earlier and has a few fixed OEM designs.
The year is looking quite good for Qualcomm, winning most of the key designs with Texas Instrument out of the picture, and Nvidia’s lengthy Tegra 4 delay. It looks like Qualcomm had to face very little competition to win all that counts this year, at least in high-end phones.
The thermal threshold for super-tablets and calm shell designs sometimes can exceed the 5W barrier, but only for a few seconds in a short burst. Anything more than that would seriously affect battery life, or potentially increase the temperature to over 45 degrees Celsius (113 F). The same principle applies for phones, where bursts over 3W are possible for a brief period.