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SN74LS245N

TISN74LS245N

Texas Instruments
Classic LS TTL octal transceiver in PDIP for legacy 5 V TTL systems where LS-level devices are preferred.
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Overview

The SN74LS245N is a classic 8-bit bidirectional bus transceiver designed for asynchronous two-way communication between data buses. It features three-state outputs and a dedicated direction control pin, making it a staple for managing data flow in 5V TTL logic systems and vintage computing hardware.

Why Choose This Part

The device includes hysteresis at the bus inputs to improve noise margins and provide cleaner signal transitions. Its PNP inputs significantly reduce DC loading on the bus lines compared to standard TTL, while the 20-PDIP package allows for easy use in breadboards and through-hole PCB designs.

Applications

Bus Interfacing
Connecting multiple peripherals or memory modules to a common 8-bit microprocessor data bus.
Signal Buffering
Boosting weak signals to drive heavy capacitive loads or long PCB traces in 5V digital systems.
Legacy Logic Level Translation
Acting as an interface between different 5V logic families where LS-level input thresholds are required.
Breadboard Prototyping
Serving as a robust, hand-solderable buffer for educational projects and 8-bit homebrew computers.

Key Specifications

Logic Type Transceiver, Non-Inverting
Output Type 3-State
Mounting Type Through Hole
Package / Case 20-DIP (0.300", 7.62mm)
Voltage - Supply 4.75V ~ 5.25V
Number of Elements 1
Operating Temperature 0degC ~ 70degC (TA)
Supplier Device Package 20-PDIP
Current - Output High, Low 15mA, 24mA
Number of Bits per Element 8

Getting Started

To use this transceiver, connect the DIR pin to control data direction and the G bar (Output Enable) pin to GND to activate the outputs. For prototyping, the 20-PDIP package fits directly into standard breadboards and requires a stable 4.75V to 5.25V power supply.

Also Consider

74HCT245 TITexas Instruments - Choose this CMOS version for lower power consumption while maintaining TTL-compatible input levels.
74HC245 TITexas Instruments - Select this if your system uses pure CMOS logic levels rather than TTL thresholds.
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