Texas Instruments SN74AC245PW

Overview

SN74AC245PW from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in mixed-voltage systems. It operates from 2 V to 6 V, accepts inputs up to 6 V, delivers ≤7 ns propagation delay at 5 V, and features independent direction (DIR) and output-enable (OE) controls for flexible bus isolation-used in pro audio signal routing and factory automation I/O expansion.

For engineers reviewing the SN74AC245PW datasheet, SN74AC245PW pinout, SN74AC245PW application, or SN74AC245PW equivalent, this page provides verified functional modes, TSSOP-20 package details, switching characteristics across VCC = 3.3 V and 5 V, thermal resistance (RθJA = 126.6 °C/W), and real-world interface design guidance for level-shifting and bus contention avoidance.

Technical Context

The SN74AC245PW implements a CMOS-based dual-bus transceiver architecture with positive-logic DIR control: low DIR enables B→A transmission, high DIR enables A→B transmission. Its 3-state outputs are fully disabled when OE is high, providing true bus isolation without leakage paths.

It supports wide-supply operation (2–6 V) with input tolerance beyond VCC (up to 6 V), enabling robust level translation between 3.3 V microcontrollers and 5 V peripherals. Edge rates are intentionally slowed to suppress output ringing on unterminated traces-critical in video signage and industrial backplane interfaces.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 6.4 mm body size, 0.65 mm lead pitch, exposed pad not present, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AC245PW, SN74LVC245APWR offers faster timing but sacrifices 5 V bus compatibility, while 74ALVC245MTCX achieves lower static power and higher speed at the cost of absolute input voltage headroom-making SN74AC245PW the only option supporting mixed 3.3 V/5 V system-level interoperability without redesign.

Availability

SN74AC245PW is available at Aetrix Electronics and suitable for pro audio signal routing, factory automation I/O expansion, video signage controller interfaces, and smart appliance communication hubs requiring stable component supply across extended product lifecycles.

Supply support for SN74AC245PW 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 connectivity technologies, with decades of experience in industrial-grade logic and interface solutions.

The SNx4AC245 product line was engineered for robust bidirectional bus interfacing in mixed-voltage industrial and professional audio systems, emphasizing voltage tolerance, noise immunity, and bus isolation reliability.

FAQ

What is the maximum operating temperature for SN74AC245PW?

The SN74AC245PW is rated for operation from −40 °C to +85 °C ambient temperature. This industrial temperature range ensures reliable performance in factory automation enclosures and pro audio equipment racks where internal temperatures may exceed consumer-grade limits. Thermal derating is required above 40 mW dissipation due to its RθJA of 126.6 °C/W in the TSSOP-20 package.

Can SN74AC245PW translate between 3.3 V and 5 V logic levels?

Yes, SN74AC245PW supports true bidirectional level translation: it operates from 2 V to 6 V VCC and accepts input voltages up to 6 V regardless of supply voltage. When powered at 3.3 V, it safely interfaces with 5 V peripherals on either A or B port without external components-verified by its VI specification (−0.5 V to VCC + 0.5 V) and 6 V-tolerant input structure.

How does the DIR pin control data flow direction in SN74AC245PW?

In SN74AC245PW, the DIR pin determines bus direction: DIR = low enables data transmission from B bus to A bus; DIR = high enables A bus to B bus. This control is asynchronous and immediate-no clocks or setup times required. The device enters high-impedance isolation only when OE is high, regardless of DIR state.

What is the recommended bypass capacitor for SN74AC245PW?

A 0.1 µF ceramic capacitor is required for SN74AC245PW, placed as close as possible (≤3 mm) to the VCC pin with a low-inductance path to GND. This minimizes supply ripple during output switching transients and prevents false triggering caused by ground bounce-especially critical given its 24 mA drive capability and 7 ns propagation delay.

Is SN74AC245PW pin-compatible with other TSSOP-20 octal transceivers?

SN74AC245PW shares the same TSSOP-20 (PW) footprint and pinout with SN74LVC245APWR and SN74LVCH245APWR, but functional differences exist: SN74LVC245APWR lacks 5 V input tolerance, and SN74LVCH245APWR adds bus-hold circuitry. Direct replacement requires verification of voltage compatibility, timing margins, and OE/DIR logic polarity in the target design.