A column circuit that amplifies signals read from a sense amplifier array
SAA to local input/output lines LIO in sub-amplifiers SAMP to transfer
the amplified signals to main input/output lines MIO is provided. A
current control circuit IC that can set one of two kinds of currents
according to read enable signals RD1, RD2 is provided in each
sub-amplifier SAMP. The read enable signals RD1, RD2 are generated at
timings corresponding to the number of cycles in burst read operation
under control of the timing controller. Current in the current control
circuit IC is set to be large by the RD1 in burst read operation cycle
just after activation of a memory bank, while current in the current
control circuit IC is set to be small by the RD2 in the next and
subsequent burst read cycles. Accordingly, expansion of an operation
margin or reduction of power consumption can be realized in a
semiconductor device including a semiconductor memory such as a DRAM.