STMicroelectronics 74VHCT245ATTR

Overview

74VHCT245ATTR from STMicroelectronics is an advanced high-speed CMOS octal bus transceiver (3-state) with directional control, operating at 4.5–5.5 V, featuring 4.5 ns typical propagation delay, ±8 mA output drive, and TTL-compatible inputs (VIH ≥ 2 V, VIL ≤ 0.8 V). It enables bidirectional data flow between two 8-bit buses in industrial control backplanes and microprocessor I/O expansion.

For engineers reviewing the 74VHCT245ATTR datasheet, 74VHCT245ATTR pinout, 74VHCT245ATTR application, or 74VHCT245ATTR equivalent, key selection criteria include direction-controlled 3-state operation, symmetrical output impedance, power-down input/output protection, latch-up immunity, and TSSOP-20 packaging for high-density PCB layouts.

Technical Context

This device implements a dual-bus, directionally gated transceiver architecture: DIR selects data flow direction (A→B or B→A), while G enables/disables all outputs into high-impedance state. All 16 I/O pins (A1–A8, B1–B8) are fully buffered with ESD protection (2 kV HBM) and dynamic noise suppression (VOLP ≤ 0.9 V).

It operates strictly within 4.5–5.5 V supply range with guaranteed DC specs across –55°C to +125°C, including VIH/VIL thresholds compatible with TTL logic families, and balanced tPLH/tPHL delays (≤1.0 ns skew) ensuring deterministic timing in synchronous bus systems.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, 1.05 mm height, lead-free and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR and 74ACT245SCX, the 74VHCT245ATTR uniquely balances 5 V TTL interoperability, ultra-low quiescent current (4 µA), and integrated power-down protection-making it optimal for industrial systems requiring both legacy compatibility and energy efficiency.

Availability

74VHCT245ATTR is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, microcontroller I/O expansion, and test equipment pattern generation requiring stable component supply across extended temperature ranges.

Supply support for 74VHCT245ATTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The VHCT logic family targets 5 V systems needing TTL compatibility with CMOS power efficiency-specifically engineered for robust, low-noise bus interfacing in harsh industrial and automotive environments.

FAQ

What is the maximum allowable input voltage on DIR and G pins?

The absolute maximum input voltage on DIR and G is –0.5 V to +7.0 V per Table 4, but recommended operating range is 0 V to VCC (5.5 V max). Exceeding VCC by more than 0.5 V risks violating the VI/O specification for bus I/O pins and may degrade ESD protection lifetime.

Can 74VHCT245ATTR operate reliably at –55°C?

Yes. The device is fully characterized from –55°C to +125°C per Table 5, with guaranteed DC parameters (VIH, VIL, VOH, VOL) and AC timing (tPD, tPZH) across this range. Industrial-grade TSSOP packaging and C2MOS process ensure mechanical and electrical stability at cryogenic temperatures.

Is external pull-up required on A/B pins during high-impedance state?

No. The device does not include internal bus-hold circuitry, but its input protection structure and low leakage (±0.25 µA) allow floating A/B pins during G = HIGH without unintended logic transitions-provided PCB traces are short and noise is controlled. External pull-ups are optional for noise-critical applications.

How does the 74VHCT245ATTR handle simultaneous switching noise (SSN)?

It limits SSN via low dynamic ground bounce (VOLP ≤ 0.9 V at CL = 50 pF) and symmetrical output drive (|IOH| = |IOL| ≥ 8 mA), reducing delta-I noise. Layout best practices-such as local VCC decoupling, ground plane integrity, and minimized trace inductance-are still required to maintain signal integrity during full-bus switching events.