Texas Instruments SN64BCT25244NT

Overview

SN64BCT25244NT from Texas Instruments is an octal 25-Ω non-inverting buffer/line driver with dual 3-state enable (1OE, 2OE), designed for incident-wave switching on 25-Ω transmission lines in memory address and clock distribution systems. It sinks 188 mA IOL, operates from −40°C to 85°C, and features high-impedance outputs during power-up/down below ~3 V.

For engineers reviewing the SN64BCT25244NT datasheet, SN64BCT25244NT pinout, SN64BCT25244NT application, or SN64BCT25244NT equivalent, key selection criteria include 25-Ω line drive capability, distributed VCC/GND noise suppression, BiCMOS low ICCZ quiescent current, and guaranteed high-impedance behavior at VCC < 3 V.

Technical Context

This device implements a BiCMOS architecture to achieve high-speed switching while minimizing ICCZ (7–11 mA typical) and output ground bounce. Its distributed VCC and GND pins reduce simultaneous switching noise across all eight drivers.

The logic supports incident-wave switching by delivering fast edge rates (tPLH/tPHL ≤ 5.6 ns at 5 V) into 25-Ω loads, with output enable propagation delays (tPZH/tPZL ≤ 9.7 ns) ensuring clean bus isolation during state transitions.

Key Specifications

Pinout & Package

SN64BCT25244NT uses a 300-mil plastic DIP (Dual In-line Package) with 24 leads. Pin spacing is 0.1 inch; body width is 0.3 inches. Package conforms to JEDEC MS-001.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal 3-state buffer applications.

Compared with SN74BCT244N and SN64BCT25244DW, the SN64BCT25244NT uniquely combines industrial temperature support, 188 mA 25-Ω drive, and guaranteed power-up Hi-Z in a through-hole DIP package-making it irreplaceable for legacy-reliant, high-noise, or thermally demanding bus designs.

Availability

SN64BCT25244NT is available at Aetrix Electronics and suitable for memory address buffering, clock distribution networks, and industrial backplane interfaces requiring stable component supply and long-term obsolescence management.

Supply support for SN64BCT25244NT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with decades of heritage in high-reliability logic families.

The SN64BCT25244NT belongs to TI's BCT (Bipolar-CMOS Transistor) logic family, engineered specifically for high-speed, low-noise, 25-Ω transmission line driving in memory, clock, and bus systems.

FAQ

What is the primary function of the SN64BCT25244NT in a digital system?

The SN64BCT25244NT functions as an octal non-inverting 3-state buffer optimized for incident-wave switching on 25-Ω transmission lines. It drives memory address buses, clock signals, and bidirectional data buses with high current (188 mA IOL), low propagation delay (≤5.6 ns), and guaranteed high-impedance behavior during power transitions-ensuring signal integrity and bus contention avoidance in dense digital systems.

Does the SN64BCT25244NT support 3.3-V logic interfacing?

No-the SN64BCT25244NT is specified only for 4.5 V to 5.5 V VCC operation and TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V). It does not support direct 3.3-V logic interfacing; level translation is required when connecting to 3.3-V microcontrollers or FPGAs. The device's internal BiCMOS structure is optimized for 5-V rail operation and 25-Ω load driving.

How does the SN64BCT25244NT handle power-up and power-down sequencing?

The SN64BCT25244NT guarantees high-impedance outputs whenever VCC falls below approximately 3 V-covering both power-up ramp and power-down collapse. This prevents bus contention in multi-driver systems during supply sequencing. The behavior is inherent to its BiCMOS input stage and requires no external reset or control logic, making it ideal for systems with asymmetric power rails or hot-swap scenarios.

What is the significance of distributed VCC and GND pins on the SN64BCT25244NT?

The SN64BCT25244NT places four VCC and four GND pins across the 24-pin DIP package to minimize simultaneous switching noise (SSN). This layout reduces voltage droop and ground bounce when all eight outputs switch concurrently-critical for maintaining signal fidelity in high-speed memory and clock distribution. It directly improves noise margin and timing stability compared to single-point power packages.

Can the SN64BCT25244NT replace the SN74LS244 in existing designs?

Not directly-the SN64BCT25244NT offers significantly higher drive strength (188 mA vs. 24 mA), faster timing (≤5.6 ns vs. ~20 ns), and 25-Ω line optimization, but requires 5-V-only operation and has different DC loading characteristics. While pin-compatible in DIP-24, redesign validation is needed for timing closure, power delivery, and termination strategy due to its BiCMOS architecture and higher current demands.