The 74HCT4514 is a high-speed Silicon-gate CMOS device. It is a 4-to-16 line decoder/de-multiplexer with four bit binary weighted address inputs pins (A0 to A3). It also contains latches, an active LOW enable input (E) and a latch enable input (LE). The 16 outputs pins (Q0 to Q15) are mutually exclusive active HIGH logic. The selection of an output is done by the data on input An, this is after pulling the latch enable pin to logic HIGH. When Latch Enable is pulled LOW, the last data present at inputs are stored in the latches and the outputs remain at their previous state. When Enable is LOW, the selected output which is determined by the contents of the latch, is HIGH. At Enable HIGH, all outputs are LOW. It is to be noted that…show more content… It features: de-multiplexing capability, multiple input enable for easy expansion, typical power dissipation of 32mW, active low mutually exclusive outputs and input clamp diodes which limit high speed termination effects.
The decoder has three bits binary weighted inputs pins labelled (A0, A1, A2) and when enabled they provide eight active LOW logic Outputs (O0 – O7) all of which are mutually exclusive. The LS138 has three Enable inputs of which two are active LOW logic (E1, E2) and one active HIGH logic (E3). All outputs are pulled HIGH unless input on pins E1 and E2 are logic LOW and E3 is logic HIGH. This multiple enable functions permits easy parallel expansion of the device to a 1-of-32 (5 lines to 32 lines) decoder with just four LS138s and one inverter. The LS138 can be used as an 8-output de-multiplexer by using one of the provided active LOW Enable pins as the data input and using the other Enable inputs for strobes signal. It is to be noted that the unused Enable inputs must be permanently tied to their correct active LOW logic level or active HIGH logic level…show more content… Each receiver converts TIA/EIA-232-F inputs to 5-V TTL/CMOS compatible levels (Stabile, 2008). These receivers have a characteristic threshold of 1.3V, a characteristic hysteresis of 0.5V, and can accept ±30V inputs. Each driver also converts TTL/CMOS input levels into higher TIA/EIA-232-F levels. It meets or exceeds TIA/EIA-232-F and ITU required recommendation V.28. Areas of application include: TIA/EIA-232-F, modems and computers, battery powered systems and terminals. It features include: two drivers and two receivers, 120kbits/s operation, 60V range about 0V, low current supply (typically 8mA) and ESD protection which exceeds JESD
