Texas Instruments SN74LVT245BDWE4

Overview

SN74LVT245BDWE4 from Texas Instruments is a 3.3-V ABT octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between 3.3-V and 5-V systems. It supports mixed-mode signal operation (5-V inputs/outputs with 3.3-V V_CC), delivers 64 mA sink current per output, achieves 1.2 ns typical propagation delay at 3.3 V, and enables hot insertion via I_off and power-up 3-state logic. It is used in legacy system interconnects bridging TTL and low-voltage buses.

For engineers reviewing the SN74LVT245BDWE4 datasheet, SN74LVT245BDWE4 pinout, SN74LVT245BDWE4 application, or SN74LVT245BDWE4 equivalent, key selection criteria include bidirectional direction control (DIR), output-enable isolation (OE), 20-pin SOIC-DW package thermal performance (θ_JA = 58°C/W), and compliance with JESD 78 Class II latch-up and JESD 22 ESD standards.

Technical Context

The SN74LVT245BDWE4 implements an Advanced BiCMOS Technology (ABT) architecture optimized for low-voltage operation while maintaining TTL-compatible input thresholds and drive strength. Its DIR-controlled dual-bus path allows real-time A→B or B→A data flow without internal arbitration logic.

Hot-insertion support is achieved through two independent circuits: I_off disables outputs when V_CC = 0 V to prevent backflow current, and power-up 3-state forces high-impedance during V_CC ramp-up (Δt/ΔV_CC ≤ 200 μs/V), eliminating bus contention during system initialization.

Key Specifications

Pinout & Package

SN74LVT245BDWE4 uses a 20-pin SOIC (DW) package with 0.300-inch body width and 1.27 mm lead pitch. Pin 1 index area is marked by a beveled corner; leads are NIPDAU-finished with MSL Level-1 rating (260°C peak reflow, unlimited floor life).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVTH245A and 74ALVC16245, SN74LVT245BDWE4 uniquely combines 5-V-tolerant I/O, 64 mA drive, and certified hot-insertion capability in a compact 20-pin SOIC package-making it the only option for legacy 5-V/3.3-V bridge applications requiring guaranteed bus isolation during power transitions.

Availability

SN74LVT245BDWE4 is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive diagnostic adapters, and embedded data acquisition modules requiring stable component supply and long-term obsolescence management.

Supply support for SN74LVT245BDWE4 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 over 50 years of innovation in industrial, automotive, and communications markets.

The SN74LVT245BDWE4 belongs to TI's 3.3-V ABT logic family, engineered specifically for seamless interoperability between legacy 5-V TTL systems and modern low-voltage digital subsystems in cost-sensitive, reliability-critical applications.

FAQ

What is the maximum operating temperature range for SN74LVT245BDWE4?

The SN74LVT245BDWE4 is rated for operation from −40°C to +85°C ambient temperature. This industrial-grade range is validated across all electrical parameters in the datasheet, including propagation delay, output drive, and input thresholds. The SOIC-DW package's θ_JA of 58°C/W ensures junction temperature remains within safe limits under typical 25°C board conditions with moderate loading. Thermal derating is required above 85°C ambient.

Can SN74LVT245BDWE4 interface a 5-V microcontroller with a 3.3-V FPGA without external level shifters?

Yes, SN74LVT245BDWE4 supports mixed-mode operation: its A and B port inputs accept 0–5.5 V signals while powered from a 3.3-V V_CC, and outputs drive 3.3-V logic levels with TTL-compatible thresholds. This eliminates external level shifters in 5-V-to-3.3-V bridging applications. However, ensure OE and DIR are driven from 3.3-V logic sources to avoid exceeding VIH/VIL specifications on control pins.

How does SN74LVT245BDWE4 support hot insertion in backplane systems?

SN74LVT245BDWE4 supports hot insertion via two integrated features: I_off circuitry disables outputs when V_CC = 0 V to block damaging backflow current, and power-up 3-state forces outputs into high-impedance during V_CC ramp-up (Δt/ΔV_CC ≤ 200 μs/V). These functions are tested per JESD78 Class II and JESD22 standards, making SN74LVT245BDWE4 suitable for live insertion into powered backplanes without bus contention.

What is the recommended pull-up resistor value for OE on SN74LVT245BDWE4?

TI recommends tying OE to V_CC through a pull-up resistor to ensure high-impedance state during power-up. The minimum value is determined by the current-sinking capability of the driver controlling OE. For standard 3.3-V CMOS drivers (I_OH = −32 mA), a 10-kΩ resistor provides sufficient margin while minimizing quiescent current. Lower values (e.g., 4.7 kΩ) improve noise immunity but increase static power draw.

Does SN74LVT245BDWE4 require external decoupling capacitors, and if so, what value?

Yes, SN74LVT245BDWE4 requires local decoupling: a 0.1-μF ceramic capacitor placed as close as possible to the V_CC (pin 11) and GND (pin 10) terminals. This suppresses high-frequency switching noise and prevents ground bounce (V_OLP < 0.8 V is specified with proper decoupling). For systems with heavy bus switching, add a 4.7-μF tantalum or polymer capacitor within 1 inch of the SOIC-DW package to stabilize bulk supply voltage.