A delay locked loop (DLL) circuit for a synchronous semiconductor memory
device which can control a delay time of a feedback loop within the DLL
circuit according to the magnitude of an external load, and a method of
generating information about a load connected to a data pin of a
synchronous semiconductor memory device are provided. The DLL circuit
includes a replica output driver delaying an internal clock signal by a
first delay time to output a first internal clock signal, the first delay
time is a delay time of the internal clock signal which is generated by
an output driver when a first load of a first magnitude is connected to
an output terminal of the output driver, and a transfer/delay circuit
transferring the first delay internal clock signal to a phase detector as
a second delay internal clock signal when the first load is connected to
the output terminal, and outputting the second delay internal clock
signal to the phase detector by delaying the first delay internal clock
signal by a second delay time, the second delay time is a delay time of
the internal clock signal which is generated by the output driver when a
second load of a second magnitude, which is larger than the first
magnitude, is connected to the output terminal.