Texas Instruments SN74LVC245AN

Overview

SN74LVC245AN from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between 1.65-V to 3.6-V buses. It supports mixed-mode signal operation (5-V inputs with 3.3-V VCC), features Ioff for live insertion and partial-power-down protection, and delivers 6.3 ns max propagation delay at 3.3 V - used in LED displays, network switches, and I/O expanders.

For engineers reviewing the SN74LVC245AN datasheet, SN74LVC245AN pinout, SN74LVC245AN application, or SN74LVC245AN equivalent, key selection criteria include voltage translation capability (5 V ↔ 3.3 V), 3-state output isolation, DIR/OE control logic, thermal performance in PDIP-20, and compatibility with industrial temperature range (–40°C to 125°C).

Technical Context

The SN74LVC245AN implements dual-directional 8-bit data routing controlled by DIR (direction) and OE (output enable) inputs. Its CMOS design enables overvoltage-tolerant inputs up to 5.5 V while operating from 1.65 V to 3.6 V, allowing seamless interfacing between 5-V legacy peripherals and 3.3-V or 1.8-V logic domains. The device uses Ioff circuitry to disable outputs during power-down, preventing back-drive current.

Functional modes are strictly defined by OE/DIR logic: when OE = L, data flows A→B (DIR = H) or B→A (DIR = L); when OE = H, all outputs enter high-impedance state regardless of DIR. Propagation delay varies with VCC (e.g., 6.3 ns typ at 3.3 V) and load capacitance, with tpd, ten, and tdis fully characterized across –40°C to 125°C.

Key Specifications

Pinout & Package

SN74LVC245AN is packaged in a 20-pin plastic dual in-line package (PDIP-20) with 2.54 mm pitch, body size 24.33 mm × 6.35 mm, and through-hole mounting. Thermal resistance RθJA = 78 °C/W per datasheet.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVCH245A, the SN74LVC245AN lacks bus-hold but offers lower cost and simpler layout; compared with 74LVC245PW, it provides through-hole reliability and easier prototyping but requires larger board area and wave-solder process support.

Availability

SN74LVC245AN is available at Aetrix Electronics and suitable for LED display interfaces, industrial I/O expansion, network switch backplanes, and motor control logic requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVC245AN 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 company specializing in analog, embedded processing, and logic solutions with over 50 years of leadership in industrial and automotive electronics.

The SN74LVC245AN belongs to TI's LVC logic family, engineered for low-voltage, high-speed, mixed-signal interfacing in cost-sensitive industrial and communications equipment where voltage translation and robustness are essential.

FAQ

What is the maximum input voltage the SN74LVC245AN can tolerate?

The SN74LVC245AN accepts input voltages up to 5.5 V on all A and B port pins, regardless of VCC level (1.65 V to 3.6 V). This overvoltage tolerance enables direct interfacing with 5-V logic without external level shifters. The absolute maximum rating for VI is –0.5 V to 6.5 V, but functional operation is guaranteed only within 0–5.5 V per the Recommended Operating Conditions table in the SN74LVC245AN datasheet.

Does the SN74LVC245AN support hot-plug or live-insertion applications?

Yes, the SN74LVC245AN supports live insertion via its Ioff feature, which disables outputs and limits off-state leakage to ±20 μA when VCC = 0 V. This prevents back-driving powered circuitry during card insertion/removal. To ensure safe operation, OE must be pulled high (e.g., via resistor to VCC) during power-up, and all unused inputs should be tied to VCC or GND per TI application note SCBA004. The SN74LVC245AN is explicitly rated for this use case in its Feature Description section.

What is the propagation delay of the SN74LVC245AN at 3.3 V?

The SN74LVC245AN has a typical propagation delay (tpd) of 3.8 ns and a maximum of 6.3 ns at VCC = 3.3 V ± 0.3 V, measured under recommended conditions (CL = 50 pF, TA = 25°C). Delay increases slightly at temperature extremes: max 7.3 ns over –40°C to 125°C. These values apply to both A→B and B→A directions and are confirmed in the Switching Characteristics table (Section 7.6) of the SN74LVC245AN datasheet.

Can the SN74LVC245AN be used for level translation between 5-V and 1.8-V systems?

Yes, the SN74LVC245AN supports down-translation from 5-V inputs to 1.8-V outputs, as documented in its Feature Description section. When VCC = 1.8 V, inputs accept up to 5.5 V, and VOH/VOL meet specifications (e.g., VOH ≥ 1.29 V at IOH = –100 μA). However, output drive strength is reduced at lower VCC: IOL = 4 mA max at VCC = 1.65 V. For reliable 1.8-V signaling, ensure load capacitance and trace impedance are minimized to maintain edge integrity.

What package type does the SN74LVC245AN use, and what are its mechanical dimensions?

The SN74LVC245AN uses a 20-pin plastic dual in-line package (PDIP-20) with standard 0.3-inch body width. Its dimensions are 24.33 mm (length) × 6.35 mm (width) × 4.57 mm (height), per TI's Mechanical Data (SLMA005). Pin pitch is 2.54 mm, and it is designed for through-hole mounting and wave soldering. Unlike surface-mount variants (e.g., TSSOP or VQFN), the SN74LVC245AN offers ease of prototyping and high-reliability mechanical retention in vibration-prone environments.