STMicroelectronics 74LVC245ATTR

Overview

74LVC245ATTR from STMicroelectronics is a low-voltage CMOS octal bus transceiver (3-state, non-inverting) with directional control (DIR) and output enable (G), operating from 1.65 V to 3.6 V. It provides bidirectional data flow between two 8-bit buses, delivers ±24 mA output drive at 3.0 V, achieves 6.3 ns max propagation delay, and features 5V-tolerant inputs - ideal for level-shifting in mixed-voltage 3.3 V/5 V system interconnects.

For engineers reviewing the 74LVC245ATTR datasheet, 74LVC245ATTR pinout, 74LVC245ATTR application, or 74LVC245ATTR equivalent, key selection criteria include bidirectional bus isolation timing, 3.3 V logic compatibility with 5 V input tolerance, symmetrical drive strength, power-down protection, and TSSOP-20 package suitability for high-density PCB layouts.

Technical Context

The 74LVC245A implements an asynchronous, non-inverting bus transceiver with independent DIR and G controls: DIR selects direction (A→B or B→A), while G enables/disables all outputs into high-impedance state. Its C2MOS process ensures latch-up immunity >500 mA and ESD robustness (HBM >2 kV).

Dynamic performance is characterized by balanced tPLH ≅ tPHL propagation delays, output skew <1 ns (at 2.7–3.6 V), and fast enable/disable times (max 10 ns). Input thresholds scale with VCC (VIH = 0.65×VCC min), supporting reliable operation across the full 1.65–3.6 V supply range.

Key Specifications

Pinout & Package

TSSOP-20 package: 6.5 mm × 4.4 mm body, 0.65 mm pitch, 1.05 mm max 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 SN74LVC245APW, the 74LVC245ATTR offers tighter propagation delay consistency and broader input voltage tolerance; versus 74ALVC245MTCX, it trades raw speed for essential 5 V compatibility and system-level robustness in mixed-voltage designs.

Availability

74LVC245ATTR is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive diagnostic interfaces, USB hub controller bridges, and PCI Express slot adapters requiring stable component supply and long-term manufacturability.

Supply support for 74LVC245ATTR 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, Switzerland, specializing in microcontrollers, power management, analog ICs, and automotive-grade components.

The 74LVC245A belongs to ST's LVC (Low-Voltage CMOS) logic family, designed specifically for energy-efficient, mixed-voltage board-level interconnect in industrial, computing, and communications equipment.

FAQ

What is the maximum clock frequency supported by the 74LVC245ATTR?

The 74LVC245ATTR does not operate on a clock; it is an asynchronous transceiver. Its usable data rate depends on propagation delay and system setup/hold timing. With 6.3 ns max tPD and balanced edges, it reliably supports bus toggle frequencies up to 80–100 MHz in well-terminated, low-capacitance layouts.

Can the 74LVC245ATTR be used with a 1.8 V supply?

Yes - the 74LVC245ATTR is fully specified from 1.65 V to 3.6 V. At 1.8 V, it delivers ±4 mA output drive, VIH = 1.17 V (min), VIL = 0.63 V (max), and tPD ≤ 12 ns, making it suitable for ultra-low-power 1.8 V FPGA I/O expansion or sensor interface buffering.

Is the TSSOP-20 package of 74LVC245ATTR RoHS compliant and lead-free?

Yes - the 74LVC245ATTR (TSSOP-20) is manufactured in STMicroelectronics' RoHS-compliant, lead-free process. The device meets JEDEC J-STD-020 moisture sensitivity level 1 (MSL1) and is compatible with standard SnPb and lead-free reflow profiles.

How should unused inputs be handled on the 74LVC245ATTR?

All unused inputs - including DIR and G - must be actively tied to VCC or GND. Floating inputs risk increased ICC, erratic output states, or oscillation due to CMOS threshold sensitivity. Unused A/B bus pins may be left unconnected only if their corresponding side is disabled via DIR/G control.