- Semiconductor memory device having DLL capable of high frequency operating during burn-in test and method of the DLL

摘要

Burn-in method of operation of the test when the semiconductor memory device, and a synchronization circuit having a delay in the operation delay in the high-frequency synchronization circuit is disclosed. The invention burn-in mode operation the semiconductor memory device with a delay to the synchronization circuit is a circuit generating a control signal to the delayed synchronization circuit for generating control signals in response to a test mode signal, and responsive to said test mode signal to a high frequency clock signal and a response to the ring oscillator and the control signals and the clock signal for generating said time-delay synchronous circuit that operates in a mode or normal mode; And a fuse or a switch for transmitting the clock signal as in the delayed synchronization circuit, embodiment the semiconductor memory device according to the present invention, conventional time-due to the clock frequency could be sufficient to test for a test to delay synchronization circuit Unlike difficult is also verification, one-time of the operation of a delay synchronization circuit is to generate a clock signal of a high frequency supplied from the mode signal illustration part ohsil ring in response to it is possible to also test the operation with the into the original delay synchronization circuit .