The VT18PLL500 is a macro cell for clock generation.
The output frequency is adjustable from 50 to 500MHz.
It is a fully integrated PLL based clock generator with a phase frequency detector (PFD), a low pass filter (LPF), a voltage controlled oscillator (VCO), and supporting circuitry such as fully programmable dividers. It is used for multiplication of stable clock source such as crystal oscillators.
Layout structure uses 1P4M (1poly and 4metal layers)
Layout does not use any special mask layer. (MIM or deep-Nwell layers are not required).