Texas Instruments SN74LVCH245ADW

Overview

SN74LVCH245ADW from Texas Instruments is an octal bus transceiver with tri-state outputs, designed for bidirectional data translation between 1.65-V and 3.6-V logic domains. It supports mixed-mode operation (5-V-tolerant inputs with 3.3-V V_CC), features I_off for live insertion and partial-power-down protection, and delivers 6.3 ns max propagation delay at 3.3 V. It is used in server backplanes and PC motherboard bus isolation.

For engineers reviewing the SN74LVCH245ADW datasheet, SN74LVCH245ADW pinout, SN74LVCH245ADW application, or SN74LVCH245ADW equivalent, key selection criteria include its 1.65–3.6-V supply range, 5.5-V input tolerance, bus-hold inputs eliminating external resistors, tri-state control via active-low OE, and SOIC-20 package compatibility with legacy 3.3-V/5-V interface designs.

Technical Context

This device implements a dual-bus, direction-controlled transceiver architecture with independent A and B ports, where DIR selects data flow direction (A→B or B→A) and OE enables/disables all outputs simultaneously. Its CMOS input structure includes integrated bus-hold latches that maintain valid logic states on floating inputs without external biasing.

The SN74LVCH245ADW integrates I_off circuitry to block current flow when V_CC = 0 V, preventing back-drive damage during hot-swap or partial-power-down sequences. All inputs tolerate up to 5.5 V regardless of V_CC, enabling safe interfacing with higher-voltage logic in mixed-supply systems.

Key Specifications

Pinout & Package

SN74LVCH245ADW is housed in a 20-pin SOIC (DW) package measuring 12.80 mm × 7.50 mm, with standard 0.65-mm lead pitch and surface-mount footprint compatible with IPC-7351B SOIC-20 guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245A and 74AVC8T245, the SN74LVCH245ADW uniquely combines 5.5-V input tolerance, I_off, and bus-hold in a single SOIC-20 package-making it the only option among the three qualified for mixed-voltage hot-swap systems with uncontrolled input states.

Availability

SN74LVCH245ADW is available at Aetrix Electronics and suitable for server backplanes, PC motherboards, and network switch interfaces requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74LVCH245ADW 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 logic solutions for industrial, automotive, and communications markets.

The SN74LVCH245ADW belongs to TI's LVCH logic family, engineered for robust mixed-voltage interfacing in high-reliability computing and infrastructure equipment where power sequencing, ESD resilience, and signal integrity are critical.

FAQ

What voltage levels can SN74LVCH245ADW safely interface between?

The SN74LVCH245ADW accepts input voltages up to 5.5 V while operating from a 1.65–3.6-V V_CC, enabling direct connection between 5-V legacy peripherals and modern 3.3-V or 1.8-V controllers. Its outputs swing rail-to-rail within V_CC, and all I/Os retain bus-hold functionality regardless of OE or DIR state. This eliminates external level-shifting components in mixed-supply systems.

How does the I_off feature protect SN74LVCH245ADW during hot-swap events?

The I_off circuitry in SN74LVCH245ADW disables all I/O paths when V_CC drops to 0 V, blocking current backflow from live buses into the unpowered device. This prevents latch-up and thermal damage during insertion/removal of daughter cards or modules. For full protection, OE should be tied to V_CC via a pullup resistor to ensure high-impedance state at power-up.

Does SN74LVCH245ADW require external pull-up or pull-down resistors on its data lines?

No. SN74LVCH245ADW includes active bus-hold circuitry on all A and B port inputs, which maintains the last-valid logic state on floating pins without external resistors. This reduces BOM count, saves PCB area, and avoids timing skew introduced by resistor-capacitor networks. Using external pull-ups/pull-downs with enabled bus-hold is not recommended.

What is the maximum data rate supported by SN74LVCH245ADW in a typical PCB layout?

With a max propagation delay of 6.3 ns at 3.3 V and output skew under 1 ns, SN74LVCH245ADW supports reliable operation on parallel buses up to 100 MHz in well-designed layouts. Real-world performance depends on trace length, load capacitance (<50 pF recommended), and termination. For >100-MHz applications, signal integrity analysis and controlled-impedance routing are advised.

Can SN74LVCH245ADW replace SN74LVC245A in an existing design without layout changes?

Yes - SN74LVCH245ADW uses the same SOIC-20 (DW) package as SN74LVC245A and shares identical pinout and footprint. However, SN74LVCH245ADW adds I_off and bus-hold, so no redesign is needed to gain enhanced robustness. Existing designs benefit immediately from improved hot-swap tolerance and elimination of external bias resistors.