Texas Instruments 74AC11245NSR

Overview

74AC11245NSR from Texas Instruments is an octal bus transceiver IC with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses. It features direction control (DIR) and output-enable (OE) inputs, operates from –40°C to 85°C, supports VCC = 3–5.5 V, and delivers tPLH/tPHL ≤ 9.5 ns at 5 V. It is used in industrial backplane interfaces requiring bus isolation and flow-through PCB layout.

For engineers reviewing the 74AC11245NSR datasheet, 74AC11245NSR pinout, 74AC11245NSR application, or 74AC11245NSR equivalent, this page provides verified functional role, real-world timing behavior, bus-isolation logic states, thermal operating range, and package-specific drive capability - all confirmed for the NSR variant.

Technical Context

The 74AC11245NSR implements dual 8-bit noninverting transceivers with independent DIR and OE controls, enabling either A→B or B→A data flow per channel. Its EPIC (Enhanced-Performance Implanted CMOS) 1-μm process ensures latch-up immunity of 500 mA at 125°C and supports rail-to-rail input/output voltage operation (0 to VCC).

It uses center-pin VCC and GND configuration in its SO (NS) package to minimize high-speed switching noise. The device achieves 16 pF power-dissipation capacitance when outputs are disabled and 64 pF when enabled (CL = 50 pF, f = 1 MHz), directly impacting dynamic power consumption in dense bus systems.

Key Specifications

Pinout & Package

The 74AC11245NSR is supplied in a 24-pin plastic small-outline (SO) package (NS), with 0.300-inch width, gull-wing leads, and JEDEC MS-012 compliant footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR and 74ACT125N, the 74AC11245NSR uniquely supports 3–5.5 V operation, integrated DIR logic, and industrial-grade latch-up immunity - making it the sole choice for mixed-voltage, hot-pluggable, or noise-sensitive backplane applications.

Availability

74AC11245NSR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, modular PLC baseboards, test equipment data muxes, and hot-swap-capable embedded controllers requiring stable component supply across extended temperature ranges.

Supply support for 74AC11245NSR 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The 74AC11245NSR belongs to TI's AC-series advanced CMOS logic family, engineered for high-speed, low-noise, and latch-up-resistant operation in industrial control and data acquisition systems.

FAQ

What is the maximum operating frequency supported by the 74AC11245NSR?

The 74AC11245NSR does not specify a maximum clock frequency but delivers guaranteed propagation delays: tPLH/tPHL ≤ 9.5 ns at VCC = 5 V. This supports reliable operation up to approximately 100 MHz in well-terminated, low-load bus configurations. Actual usable frequency depends on PCB layout, capacitive loading, and signal integrity margins - design validation at target speed is required. The 74AC11245NSR is not a clocked device but a combinatorial transceiver, so timing is governed by propagation and transition metrics, not clock period.

Does the 74AC11245NSR support 3.3-V logic levels when powered at 5 V?

Yes, the 74AC11245NSR accepts 3.3-V logic inputs at VCC = 5 V: VIH(min) = 3.15 V and VIL(max) = 1.35 V at VCC = 4.5 V, providing 0.15-V margin above 3.3-V logic HIGH. Its outputs swing rail-to-rail (0 to 5 V), so external level translation is needed to interface with 3.3-V receivers. The 74AC11245NSR itself does not perform voltage translation - it buffers and isolates, not shifts.

How many ground pins does the 74AC11245NSR have in its NS package?

The 74AC11245NSR in the NS (24-pin SO) package has four dedicated ground pins: pins 5, 6, 7, and 8. This multi-GND configuration lowers impedance in high-speed switching paths and reduces ground bounce - a key design feature confirmed in the device's mechanical drawing and functional description. These pins must be connected to a low-impedance ground plane for optimal noise performance.

Can the 74AC11245NSR be used in hot-swap applications?

Yes, the 74AC11245NSR supports hot-swap operation via its 3-state OE control: asserting OE = High places all A and B pins in high-impedance mode, electrically isolating both buses before power-up or during live insertion. Its 500-mA latch-up immunity at 125°C further enhances robustness against transient overstress during plug-in events. However, external current-limiting and sequencing circuitry may still be required depending on system-level fault conditions.

What is the difference between the 74AC11245NSR and the 74AC11245DWR?

The 74AC11245NSR and 74AC11245DWR share identical logic function, AC electrical specifications, and thermal ratings, but differ in package: NSR is a 24-pin SO (0.300-inch width), while DWR is a 24-pin SOIC (DW) with narrower 0.300-inch body but different leadform and moisture sensitivity level (MSL). Pinout and DC parameters are identical; only mechanical fit, reflow profile, and tape-and-reel packaging differ. Both are active, RoHS-compliant, and functionally interchangeable where board layout permits.