The New Providence Wharf scheme already boasts a 104m-tall tower, currently under construction, but the practice's new Building C will top that, standing at 136m.
The new 44-storey tower will be accompanied by an 11-storey wing, which will offer 499 new homes.
An original design contained offices, but that has been scrapped to provide extra homes.
The new building resembles the adjacent Ontario Tower, mimicking the lipstick shape, but slopes in the opposite direction, and has a stepped appearance.
The balconies and cladding will be designed to appear as if they are 'woven' into the facade, and the tower will be topped with a green roof.
The development has been backed by Ballymore, which has commissioned SOM to design the entire Docklands project.
The tower is the third 100m-tall building to be proposed by the developers for this project in the past 18 months.