مدار مجتمع (آی سی) آی سی‌کاربرد ویژه

Product Attributes

Introduction

The 253 is a dual 4-input multiplexer with three-state outputs. It allows selection of two bits of data from four sources using common select inputs. The outputs can be individually switched to a high-impedance state by driving the corresponding output enable (OE̅) input high, enabling the outputs to interface directly with bus-oriented systems. Fabricated using Schottky barrier diode process technology, it offers high-speed performance and is fully compatible with all Fairchild TTL families. The device contains two identical 4-input multiplexers with three-state outputs. They select two bits of data from four sources via common select inputs (S0, S1). The 4-input multiplexers have individual output enable (OEa, OEb) inputs which, when driven high, force the outputs into the high-impedance (high-Z) state. The device is a logic implementation of a 2-pole, 4-position switch, with the switch position determined by the logic levels applied to the two select inputs. The logic equations for the outputs are as follows: Za = O̅E̅a̅ × (I0a × S̅1 × S̅0 + I1a × S̅1 × S0 + I2a × S1 × S̅0 + I3a × S1 × S0); Zb = O̅E̅b̅ × (I0b × S̅1 × S̅0 + I1b × S̅1 × S0 + I2b × S1 × S̅0 + I3b × S1 × S0). If the outputs of three-state devices are connected together, all but one device must be in the high-impedance state to avoid high currents that exceed the maximum ratings. Designers should ensure that the output enable signals of three-state devices connected together are properly designed to prevent overlap.

Features

• High-speed performance via Schottky process
• Versatile functionality
• Non-inverting tri-state outputs