SN54LS374 Datasheet | Texas Instruments

description These 8-bit registers feature 3-state outputs designed specifically for driving highly capacitive or relatively low-impedance loads. The high-impedance 3-state and increased high-logic-level drive provide these registers with the capability of being connected directly to and driving the bus lines in a bus-organized system without need for interface or pullup ponents. These devices are particularly attractive for implementing buffer registers, I/O ports, bidirectional bus drivers, and working registers. The eight latches of the ’LS373 and ’S373 are transparent D-type latches, meaning that while the enable (C or CLK) input is high, the Q outputs follow the data (D) inputs. When C or CLK is taken low, the output is latched at the level of the data that was set up. SN54LS373, SN54LS374, SN54S373, SN54S374 . . . J OR W PACKAGE SN74LS373, SN74S374 . . . DW, N, OR NS PACKAGE SN74LS374 . . . DB, DW, N, OR NS PACKAGE SN74S373 . . . DW OR N PACKAGE (TOP VIEW) OC 1Q 1D 2D 2Q 3Q 3D 4D 4Q GND 1 2 3 4 5 6 7 8 9 10 20 VCC 19 8Q 18 8D 17 7D 16 7Q 15 6Q 14 6D 13 5D 12 5Q 11 C† † C for ’LS373 and ’S373; CLK for ’LS374 and ’S374. SN54LS373, SN54LS374, SN54S373, SN54S374 . . . FK PACKAGE (TOP VIEW) 2D 3 2 1 20 19 4 18 8D 2Q 5 17 7D 3Q 6 16 7Q 3D 7 15 6Q 4D 8 14 6D 9 10 11 12 13 4Q 1D GND 1Q C† OC 5Q VCC 5D 8Q The eight flip-flops of the ’LS374 and ’S374 are edge-triggered D-type flip-flops. On the positive transition of the clock, the Q outputs are set to the logic states that were set up at the D inputs. † C for ’LS373 and ’S373; CLK for ’LS374 and ’S374. Schmitt-trigger buffered inputs at the enable/clock lines of the ’S373 and ’S374 devices simplify system design as ac and dc noise rejection is improved by typically 400 m V due to the input hysteresis. A buffered output-control (OC) input can be used to place the eight outputs in either a normal logic state (high or low logic levels) or the high-impedance state. In the high-impedance state, the...