Both read enables can be driven together in some (E.g. CY7C42x1 and CY7C42x1V) families of synchronous FIFOs. Two read enable signals are provided to simplify depth expansion. In depth expansion, two FIFO's are used together to double the overall depth. Having two /REN signals allows the controller to switch between the two devices and control the flow of data. Otherwise, in standalone or width expansion mode, these two signals can be shared.