Delay locked loop in semiconductor memory device and method for generating divided clock therein

Abstract

Provided are a delay locked loop (DLL) and a method for generating a divided clock therein. In the DLL, a width of a reference frequency for phase comparison can be changed depending on a magnitude of an operating frequency. In the DLL, a clock buffer receives a clock equal to an external clock and generates an internal clock. An enable clock generator generates a 1-period enable clock or a 2-period enable clock using a command signal generated for performing a predefined operation. The command signal is generated according to an address command signal inputted from an exterior. A clock divider divides the internal clock to generate a divided clock. The divided clock is controlled by the 1-period enable clock or the 2-period enable clock, such that the divided clock is made to be a 1-period based dividing clock or a 2-period based dividing clock.