The Programmable Delay cell has four internal delay cells with a typical value of 20ns per cell. The delay cells are tied in series where the output of each delay cell goes to the next delay cell and to a 4-input multiplexer.

Programmable Delay is configured once and cannot be changed. The Delay time depends on the number of cells chosen and supply voltage. The number of delays cells are selected in the Delay option of the properties window.