Texas Instruments SN74ABT2245N

Overview

SN74ABT2245N from Texas Instruments is an octal transceiver and line driver with 3-state outputs, designed for asynchronous bidirectional data bus communication between A- and B-buses. It features direction control (DIR), output enable (OE), B-port outputs with integrated 25-Ω series resistors, and operates over –40°C to 85°C at 4.5–5.5 V supply. Used in industrial backplane interfaces and legacy bus isolation.

For engineers reviewing the SN74ABT2245N datasheet, SN74ABT2245N pinout, SN74ABT2245N application, or SN74ABT2245N equivalent, key selection considerations include its 20-pin PDIP package, 3.85 V VOH (B-port, IOH = –1 mA), 0.65 V VOL (B-port, IOL = 8 mA), 3.4 ns max tPHL (A→B), and high-impedance state during power-up below 2.1 V.

Technical Context

This BiCMOS transceiver implements dual-directional data flow controlled by DIR and enables/disables all outputs via OE. Its B-port outputs integrate 25-Ω series resistors to suppress overshoot/undershoot without external components, while A-port outputs support higher drive strength (64 mA sink).

The device ensures robust bus isolation: when OE is high, both ports enter high-impedance state regardless of DIR; during power ramp (0–2.1 V), internal logic forces high-Z even if OE is floating. Latch-up immunity exceeds 500 mA per JESD-17, and ESD protection meets 2000 V HBM and 200 V machine model.

Key Specifications

Pinout & Package

SN74ABT2245N uses a 20-pin plastic dual in-line package (PDIP-N), 0.300" wide, with standard through-hole mounting and JEDEC MS-013 outline. Pin 1 is located at top-left corner with notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ABT245N and SN74LVC245APW, SN74ABT2245N uniquely balances 5-V bus compatibility, integrated B-port termination, and single-OE simplicity - making it the preferred choice for cost-sensitive, noise-critical industrial backplanes where layout space and signal integrity are constrained.

Availability

SN74ABT2245N is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus isolation, programmable logic I/O expansion, and embedded controller peripheral bridges requiring stable component supply and long-term obsolescence management.

Supply support for SN74ABT2245N 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74ABT2245N belongs to TI's ABT logic family - engineered for high-speed, low-noise 5-V bus interfacing with enhanced ESD/latch-up robustness and integrated signal integrity features like on-die termination.

FAQ

What is the maximum operating temperature range for SN74ABT2245N?

The SN74ABT2245N is characterized for operation from –40°C to +85°C. This industrial-grade temperature range ensures reliable performance in factory automation, motor control, and outdoor embedded systems where ambient conditions exceed commercial limits. The SN54ABT2245 variant extends to –55°C to +125°C for military applications, but SN74ABT2245N itself is not rated beyond +85°C.

Does SN74ABT2245N require external pull-up resistors on OE or DIR pins?

No external pull-up resistors are required on OE or DIR for basic functionality. However, to guarantee high-impedance state above 2.1 V during power-up, TI recommends tying OE to VCC via a pullup resistor - minimum value determined by driver capability. DIR may be left unconnected only if fixed direction is used; otherwise, it must be actively driven to avoid floating logic states that cause undefined bus behavior in SN74ABT2245N.

Can SN74ABT2245N interface directly with 3.3-V logic devices?

SN74ABT2245N is a 5-V-only device with VIH = 2.0 V and VIL = 0.8 V, making it compatible with 3.3-V CMOS/TTL output levels (which typically swing 0–3.3 V). However, its outputs swing 0–5 V, so direct connection to 3.3-V inputs requires level translation or clamping to avoid overvoltage damage. SN74ABT2245N does not support 3.3-V supply operation and must be powered from 4.5–5.5 V.

What is the purpose of the 25-Ω series resistors on the B-port outputs of SN74ABT2245N?

The 25-Ω series resistors on SN74ABT2245N's B-port outputs are integrated to damp signal reflections on transmission lines, reducing overshoot and undershoot in medium-length bus traces (e.g., 10–30 cm). They eliminate the need for discrete 25-Ω resistors near connectors or stubs, simplifying layout and improving signal integrity without increasing component count or board area.

How does SN74ABT2245N behave during power-up and power-down sequences?

When VCC is between 0 and 2.1 V, SN74ABT2245N automatically enters a high-impedance state on all I/Os - preventing bus contention before supply stabilization. Above 2.1 V, OE must be actively controlled: if OE is high, outputs remain high-Z; if OE is low, direction and data flow follow DIR and bus states. This behavior is intrinsic to SN74ABT2245N and requires no external reset circuitry.