The PI74FCT138TQ is a high-speed 3-to-8 line decoder/demultiplexer manufactured by Pericom Semiconductor (now Diodes Incorporated). It is designed for memory decoding or data routing applications that require high performance.

Applications

• Memory address decoding
• Data routing and distribution
• Chip select generation
• Logic function generation
• Instrumentation and control systems

Features

• 3-to-8 line decoder/demultiplexer
• High-speed operation
• Low power consumption
• Three enable inputs (G1, G2A, G2B)
• Active-low outputs
• TTL compatible inputs
• Available in QSOP package

Benefits

• Efficient memory address decoding
• Flexible data routing capabilities
• Reduced power consumption
• Simplified system design with multiple enable inputs
• Direct interface with other logic devices

Additional Details

The PI74FCT138TQ is a 3-to-8 line decoder/demultiplexer that decodes one of eight outputs based on the three binary select inputs (A0, A1, A2). The device features three enable inputs (G1, G2A, G2B) to facilitate easy cascading and memory chip selection. The outputs are active-low, meaning that only one output is low at any given time, corresponding to the selected input combination, while all other outputs are high. The enable inputs must be properly asserted (G1 = HIGH, G2A = LOW, G2B = LOW) for the decoder to be active; otherwise, all outputs will be high.

This device is designed for high-speed operation with low power consumption, making it suitable for a wide range of applications including memory address decoding, data routing, and chip selection. The TTL-compatible inputs ensure easy interface with other logic devices. The availability in a QSOP package allows for high-density board designs. The PI74FCT138TQ is particularly useful in systems where multiple memory devices or peripherals need to be selected based on an address or control signal. Its low propagation delay contributes to faster system performance. The multiple enable inputs are useful for hierarchical decoding schemes, enabling more complex address decoding architectures.