http://www.fudzilla.com/home/item/35355-5th-generation-broadwell-14nm-family-comes-in-three-lines
 
The differences in the three different Broadwell lines for mobile. Based on that and other info around the web, initial Broadwell for mobile parts will consist of the Core M 5Y70, 5Y10, and 5Y10a, all of which are BGA parts. Both the Core M 5Y70 and 5Y70a are dual-core parts clocked at 800MHz to 2GHz with 4MB of L3 cache, integrated GPU clocked at 100MHz to 800MHz, and a 4.5W TDP, though the 5Y70 is configurable to also run at 4W. As for the 5Y70, it's a dual-core chip with Hyper-Threading support that runs at 1.1GHz to 2.6GHz with 4MB of L3 cache, 100MHz to 850MHz GPU, and 4.5W TDP.
Next up is the U Series that will also come in BGA form and TDPs ranging from 15W to 28W.These will be dual-core parts designed for Ultrabooks and NUC configurations with support for up to 16GB of DDR3L-1600 memory or 8GB of LPDDR3-1600. Finally, the H Series will also ship in BGA form with a 47W TDP. These will be the chips that end up in high-end systems.