Texas Instruments SN74ACT245PW

Overview

SN74ACT245PW from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data bus communication between 5-V logic domains. It operates from 4.5 V to 5.5 V, delivers ≤8 ns propagation delay at 5 V, and accepts input voltages up to 5.5 V - enabling robust interfacing in industrial control backplanes and mixed-voltage system interconnects.

For engineers reviewing the SN74ACT245PW datasheet, SN74ACT245PW pinout, SN74ACT245PW application, or SN74ACT245PW equivalent, this page provides verified functional modes, thermal resistance (RθJA = 126.6 °C/W), output drive capability (±24 mA), and precise TSSOP-20 pin mapping - all confirmed for the exact PW package variant.

Technical Context

The SN74ACT245PW implements dual-directional 8-bit data flow controlled by DIR (direction) and OE (output enable) inputs, supporting A→B or B→A transfer with high-impedance isolation when OE is high. Its ACT-family CMOS process ensures TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V) and overvoltage-tolerant inputs (up to 5.5 V).

Switching behavior is characterized by tPLH/tPHL ≤9 ns and tPZH/tPLZ ≤12 ns at 5 V, with slow edge rates minimizing output ringing in noise-sensitive applications like pro audio signal routing and factory automation I/O modules.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5 mm × 6.4 mm body size, 1.2 mm max height, lead pitch 0.65 mm, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT245PW, SN74LVC245APWR targets 3.3-V domains and lacks 5-V tolerance, while SN74AHCT245PW offers pin compatibility but sacrifices 33% output current - making SN74ACT245PW optimal for robust 5-V industrial interconnects demanding full drive and overvoltage resilience.

Availability

SN74ACT245PW is available at Aetrix Electronics and suitable for pro audio signal routing, video signage backplane interfaces, and factory automation I/O expansion requiring stable component supply across extended temperature ranges (–40°C to +85°C).

Supply support for SN74ACT245PW 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 for industrial, automotive, and communications markets.

The SN74ACT245PW belongs to TI's ACT-family advanced CMOS logic line, engineered for high-noise-immunity 5-V system interconnects where timing precision, bus isolation, and overvoltage resilience are critical.

FAQ

What is the maximum operating temperature for the SN74ACT245PW?

The SN74ACT245PW is rated for operation from –40°C to +85°C ambient temperature. Its TSSOP-20 package exhibits a junction-to-ambient thermal resistance (RθJA) of 126.6 °C/W, meaning it can dissipate up to 315 mW continuously at 85°C ambient before exceeding the 150°C maximum junction temperature. Derating is required above 70°C ambient per TI's thermal guidelines.

Does the SN74ACT245PW support 3.3-V logic inputs?

No - the SN74ACT245PW is a 5-V-only device with TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and requires VCC = 4.5–5.5 V. While its inputs tolerate up to 5.5 V, they are not guaranteed to recognize 3.3-V logic highs reliably without external pull-up biasing. For 3.3-V systems, consider SN74LVC245A instead.

How does the DIR pin control data flow direction in the SN74ACT245PW?

In the SN74ACT245PW, the DIR pin sets bidirectional data path direction when OE is low: DIR = Low enables B-to-A transfer (data flows from pins 11–18 to pins 2–9); DIR = High enables A-to-B transfer (data flows from pins 2–9 to pins 11–18). When OE is high, both ports enter high-impedance state regardless of DIR state.

Can the SN74ACT245PW drive standard 50-Ω transmission lines?

Yes - the SN74ACT245PW delivers ±24 mA output current at VOH/VOL specifications, sufficient to drive unterminated 50-Ω lines with <1 V swing (e.g., 5 V into 50 Ω = 100 mA, so 24 mA supports ~2 V swing). For full 5-V swing, use series termination (e.g., 33 Ω) at the source; the SN74ACT245PW's slow edge rates inherently reduce reflections.

Is the SN74ACT245PW pin-compatible with other TSSOP-20 bus transceivers?

Yes - the SN74ACT245PW shares identical TSSOP-20 (PW) pinout and footprint with SN74AHCT245PW and SN74LVC245APWR, including DIR, OE, A/B port assignments and power/ground locations. However, voltage ranges and drive strengths differ: verify VCC compatibility and load requirements before substitution.