The present disclosure relates to a data out buffer and a memory device having the same. The data out buffer includes a pull-up main driver, coupled between a power supply terminal and an output terminal, configured to output data of a high level; and a pull-down main driver, coupled between the output terminal and a ground terminal, configured to output data of a low level, wherein the pull-up main driver comprises a main pull-up transistor of a first type; and a plurality of first trim transistors, each of a second type.