DM74ALS240ASJX

Logic - Buffers, Drivers, Receivers, Transceivers

As an integrated circuit (IC) semiconductor device, the DM74ALS240ASJX models a 3-state octal buffer and line driver (3-State Octal Buffer/Line Driver) which can send out 3-level signals, that is, the output signals are to be L (low level), H (high level) and Z (High Impedance). The DM74ALS240ASJX is suitable for buffering and line driver of the address and data bus of electronic products such as personal computers. The chip also finds application in telecommunication, test equipment, and industrial control.

Working Principle

The basic operating principle of the DM74ALS240ASJX device is the transmission of 3-state signals, with one input terminal and one output terminal. When any of the inputs (A0-7) is LOW, the corresponding output terminal (Y0-7) also goes LOW. Similarly, when any of the inputs is HIGH, the corresponding output will also go HIGH. When all 8 of the transistor inputs are at logic state "Z", the corresponding output will remain in the High Impedance state and thus maintain the data in the buses.

The DM74ALS240ASJX chip has an active LOW Direction Control input (L-D), which sets the level read and write functions for data input and output. When L-D is LOW, the 8-bit output buffer works in a read mode. When the L-D is HIGH, the 8-bit output buffer works in a write mode. Additionally, the input circuit is designed with an electro-static discharge (ESD) protection circuit, which offers a level of protection for connected components from damage caused by static electricity.

The DM74ALS240ASJX device also includes a system active latch (SL), which operates when it detects LOW-level signals. The SL can be used to determine the input signal of the data bus and activate the corresponding buffer, while the output signal remains in a High Impedance state (without data output). This control signal SL provides a useful means of protecting the data bus.

Structure & Characteristics

The DM74ALS240ASJX consists of several components: an 8-bit buffer/driver, ESD protection network and shift circuitry. This device includes 8 non-inverted buffer/driver circuits and 8 3-state buffers/drivers. Each contains an open-collector output, direct grounding and RESET (active LOW), with the operating voltage range of 4.5-5.5V, and a typical supply current of 1.6 mA. This chip operates on temperatures ranging from -40C to +85C.

The DM74ALS240ASJX is manufactured with a low power supply current (1.6 mA) and a low level of noise and crosstalk (<0.8 mV), making it ideal for high speed operation, such as memory and bus buffering systems. Additionally, the wide voltage range (4.5-5.5V) ensures that the device is compatible with both classic and advanced CMOS technology.

Conclusion

The DM74ALS240ASJX is a great choice for buffering and line driving applications as it is economical, consumes low power, and ensures reliable operation in high speed systems. Its 3-state output and ESD protection circuitry make it an excellent choice for ensuring data security in a variety of applications. Its wide operating voltage range allows it to work with both classic and advanced CMOS technology, maximizing its performance. As such, it is ideal for many electronic applications, from PC address and data buses, to telecommunication, test equipment and industrial control.