Texas Instruments SN74BCT245PWR

Overview

SN74BCT245PWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in 5-V TTL systems. It features direction control (DIR), output enable (OE), ±128 mA sink capability on B-port outputs, 7 ns max propagation delay at 5 V/50 pF, and operates from 0°C to 70°C. It is commonly used in memory address register buffering and system-level bus isolation.

For engineers reviewing the SN74BCT245PWR datasheet, SN74BCT245PWR pinout, SN74BCT245PWR application, or SN74BCT245PWR equivalent, key selection criteria include 3-state bus driving strength, DIR/OE logic interface compatibility, thermal performance in TSSOP-20 packaging, and industrial-grade 5-V TTL signal integrity requirements.

Technical Context

The SN74BCT245PWR implements dual-octet bidirectional data paths controlled by a single DIR input: low DIR enables B→A transmission, high DIR enables A→B transmission. Its 3-state outputs are independently disabled via OE, providing full bus isolation when high.

It uses bipolar TTL circuitry with BCT (Bipolar CMOS-TTL) process technology, delivering TTL-compatible input thresholds (VIH = 2 V min, VIL = 0.8 V max) and robust output drive (IOL = 64 mA max on B port). ESD protection exceeds 2000-V HBM per JESD22-A114-A.

Key Specifications

Pinout & Package

TSSOP-20 package (PW), 6.95 mm × 4.4 mm × 1.2 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bus transceiver applications.

Compared with SN74BCT245PWR, SN74LVC245APWR enables lower-voltage operation but requires level translation for 5-V buses, while SN74ABT245PWR delivers measurable timing and noise-performance gains with zero layout change.

Availability

SN74BCT245PWR is available at Aetrix Electronics and suitable for industrial control backplanes, legacy bus extension systems, and memory subsystem buffering requiring stable component supply and long-term obsolescence management.

Supply support for SN74BCT245PWR 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 over 90 years of innovation in industrial, automotive, and communications markets.

The SN74BCT245PWR belongs to TI's legacy BCT logic family, engineered specifically for robust 5-V TTL bus interfacing in mission-critical industrial and computing infrastructure where reliability and signal integrity outweigh ultra-low power demands.

FAQ

What is the maximum operating temperature range for SN74BCT245PWR?

The SN74BCT245PWR is rated for operation from 0°C to 70°C ambient temperature. This commercial-grade specification aligns with its TSSOP-20 packaging and intended use in non-military industrial and computing applications. The device must be derated above 70°C ambient per its θJA = 83°C/W thermal resistance to avoid junction temperature exceeding 150°C.

Does SN74BCT245PWR support hot-swapping on live buses?

SN74BCT245PWR supports controlled hot-swap operation when OE is asserted high before insertion to place all I/Os in high-impedance state. However, it lacks built-in bus-hold or power-up 3-state default behavior - external pull-up/down resistors and sequenced OE activation are required to prevent glitches during plug-in. The 2000-V HBM ESD rating aids handling robustness but does not guarantee live-insertion safety without system-level design.

Can SN74BCT245PWR interface directly with 3.3-V logic devices?

No - SN74BCT245PWR is a 5-V-only device with TTL-compatible input thresholds (VIH ≥ 2 V, VIL ≤ 0.8 V) and 5-V output swing. Direct connection to 3.3-V CMOS inputs risks overvoltage damage or logic misinterpretation. Level-shifting circuitry (e.g., TI SN74AVC4T245 or passive resistor dividers) is required for safe interoperability with 3.3-V systems.

What is the recommended decoupling for SN74BCT245PWR?

TI recommends a minimum 0.1-µF ceramic capacitor placed within 3 mm of the SN74BCT245PWR VCC and GND pins, plus a bulk 4.7-µF tantalum or aluminum electrolytic capacitor per 5–10 devices on the same 5-V rail. This mitigates simultaneous switching noise from up to eight 64-mA output transitions and maintains stable VCC during tPLZ/tPZH transitions.

How does the DIR input affect timing when switching data direction?

When DIR changes state, SN74BCT245PWR exhibits no added propagation delay beyond its specified tPLH/tPHL (≤7 ns). However, valid data transfer only occurs after DIR settles and OE is low - setup time (tsu) of 3 ns relative to DIR edge is required per TI test conditions. Direction reversal must therefore be synchronized with OE control to avoid bus contention during transitional states.