dac q2 walk
Well, Q2 Random Walk depends on randomizing the error so that the residual error is minimized. Hence the linear and quadratic errors are minimal, when a given current source is divided into smaller pieces and put in four quadrants.
The idea of random placement is to avoid the quadratic errors. Hence, there should not be proper order in which the cells are placed. Please make sure that you have a random placement of each current source and make sure that the same point is not repeated.
A simple suggestion, there is no need to use Q2 Random walk sequence unless you are designing a very high accuracy DAC on a very very stable process. The routing difficulty and overhead will not give the extra boost in a normal process