these devices contain four independent 2-input nand gates. the open-collector outputs require pull-up resistors to perform correctly. they may be connected to other open-collector outputs to implement active-low wired-or or active-high wired-and functions. open-collector devices are often used to generate higher voh levels. the sn5401 and sn54ls01 are characterized for operation over the full military temperature range of -55c to 125c. the sn7401 and sn74ls01 are characterized for operation from 0c to 70c.