Texas Instruments SN74LV245APWRE4

Overview

SN74LV245APWRE4 from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for bidirectional asynchronous data transfer between voltage domains. It operates from 2 V to 5.5 V, delivers ≤6.5 ns propagation delay at 5 V, supports mixed-mode I/O (e.g., 5-V inputs into 3.3-V system), and features Ioff partial-power-down protection. It is used in LED display column drivers where level-shifting and bus isolation are required.

For engineers reviewing the SN74LV245APWRE4 datasheet, SN74LV245APWRE4 pinout, SN74LV245APWRE4 application, or SN74LV245APWRE4 equivalent, key selection criteria include VCC range compatibility, direction-control logic behavior, 3-state timing margins, and thermal performance in TSSOP-20 packaging for high-density PCB layouts.

Technical Context

The SN74LV245APWRE4 implements dual-bus bidirectional data flow controlled by a single DIR input and enabled/disabled via OE. Its CMOS design ensures balanced drive strength and low ground bounce (<0.8 V at 3.3 V), with output undershoot >2.3 V under dynamic switching - critical for signal integrity in noise-sensitive telecom infrastructure backplanes.

It integrates Ioff circuitry that disables outputs during power-down, preventing backflow current when VCC = 0 V, and accepts overvoltage inputs up to 5.5 V regardless of VCC - enabling robust down-translation from 5-V logic to 3.3-V or 2.5-V buses without external level shifters.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.50 mm × 4.40 mm body, 0.65 mm lead pitch, exposed pad optional, 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 74LVC245A and SN74ALVC245, the SN74LV245APWRE4 uniquely balances wide VCC range (2–5.5 V), guaranteed Ioff, and overvoltage-tolerant I/O - making it optimal for heterogeneous voltage domain bridging where safety and compatibility supersede raw speed.

Availability

SN74LV245APWRE4 is available at Aetrix Electronics and suitable for LED display driver modules, telecom line card interfaces, and industrial I/O expander designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LV245APWRE4 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, automotive, and communications IC design.

The SN74LV245A belongs to TI's LV logic family - engineered for low-voltage operation with robust noise immunity and mixed-voltage interoperability, targeting bus interface applications in harsh environments.

FAQ

What is the maximum propagation delay of the SN74LV245APWRE4 at 3.3 V?

The SN74LV245APWRE4 has a maximum propagation delay (tpd) of 11 ns at VCC = 3.3 V, CL = 15 pF, and TA = –40°C to +125°C. This value is specified in the switching characteristics table and reflects worst-case timing under full industrial temperature range - critical for synchronous bus timing budgeting in network switch control planes.

Does the SN74LV245APWRE4 support true 5-V tolerant inputs when VCC = 3.3 V?

Yes, the SN74LV245APWRE4 supports input voltages up to 5.5 V on all A/B port pins regardless of VCC setting, including when VCC = 3.3 V. This overvoltage tolerance is explicitly guaranteed in the Absolute Maximum Ratings and Recommended Operating Conditions sections of the datasheet, enabling direct connection to 5-V microcontrollers without external protection.

How does the Ioff feature function in the SN74LV245APWRE4 during power-down?

The Ioff feature in the SN74LV245APWRE4 disables all output buffers when VCC = 0 V, limiting leakage current to ≤5 µA even if signals remain present on A/B ports. This prevents backflow current that could damage upstream drivers or cause unintended logic states - a key requirement for hot-swap-capable telecom and server backplanes.

What is the thermal resistance (RθJA) of the SN74LV245APWRE4 in its TSSOP-20 package?

The SN74LV245APWRE4 in the PW (TSSOP-20) package has a junction-to-ambient thermal resistance (RθJA) of 101.5°C/W, as specified in Section 6.4 of the datasheet. This value assumes standard JEDEC 2S2P test board conditions and informs thermal design for continuous 16-mA-per-pin operation in enclosed industrial enclosures.

Can the SN74LV245APWRE4 be used for bidirectional I²C level shifting?

No, the SN74LV245APWRE4 is not suitable for I²C level shifting because it lacks open-drain outputs and relies on active push-pull drive with direction control - incompatible with I²C's wired-AND topology and bidirectional SDA/SCL signaling without external pull-ups and arbitration logic.