onsemi 74LCXH245WM

Overview

74LCXH245WM from ON Semiconductor is a low-voltage bidirectional transceiver with bushold functionality, designed for 2.3V–3.6V bus interfacing between mixed-voltage domains. It features 8-bit non-inverting data paths, 3-STATE outputs controlled by OE and T/R inputs, ±24 mA drive at 3.0V, and 7.0 ns max propagation delay at VCC = 3.3V - enabling reliable level-shifting in compact embedded control buses.

For engineers reviewing the 74LCXH245WM datasheet, pinout, applications, or equivalent options, key selection criteria include bushold-enabled floating-input immunity, 5V-tolerant control pins (OE/T/R), 20-pin SOIC package compatibility, and verified operation across −40°C to +85°C industrial temperature range.

Technical Context

The 74LCXH245WM implements dual-directional data flow via a single T/R control signal, with independent 3-STATE enable via OE - supporting both A→B and B→A transfer without external logic. Its bushold circuitry actively maintains valid logic levels on all A0–A7 and B0–B7 I/Os when un-driven, eliminating need for external pull-up/down resistors.

Designed using advanced CMOS process, it achieves high-speed performance while maintaining low ICC (≤10 µA quiescent) and robust ESD protection (>2000V HBM). All I/Os tolerate 5V inputs regardless of VCC, enabling safe interfacing with legacy 5V controllers while operating at 2.5V/3.3V core logic levels.

Key Specifications

Pinout & Package

74LCXH245WM is housed in a 20-lead Small Outline Integrated Circuit (SOIC) package per JEDEC MS-013, 0.300" wide (Package Number M20B), with standard 1.27 mm pitch and gull-wing leads suitable for reflow soldering.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LCXH245WM, SN74LVC245APWR lacks bushold and increases BOM complexity, while 74ALVC16245PAG offers double the width but no bushold and requires PCB redesign - making 74LCXH245WM optimal for compact, robust 8-bit mixed-voltage interconnects.

Availability

74LCXH245WM is available at Aetrix Electronics and suitable for industrial PLC backplanes, embedded microcontroller bus extensions, FPGA configuration paths, and automotive body control modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74LCXH245WM 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power management, analog, logic, and discrete devices for automotive, industrial, cloud computing, and IoT applications.

The 74LCXH245WM belongs to the LCX family of low-voltage CMOS logic devices, engineered specifically for mixed-voltage system interfacing with emphasis on bushold stability, ESD robustness, and industrial temperature operation.

FAQ

What is the bushold function in the 74LCXH245WM and how does it benefit circuit design?

The bushold function in the 74LCXH245WM actively maintains valid logic states on all 16 I/O pins (A0–A7 and B0–B7) when un-driven, eliminating the need for external pull-up or pull-down resistors. This reduces BOM cost, saves PCB area, and improves reliability in hot-swap or partial-bus-enable applications. For the 74LCXH245WM, bushold current is specified at ±45 µA minimum at VCC = 2.3V, ensuring robust state retention even at lowest operating voltage.

Can the 74LCXH245WM interface safely between a 5V microcontroller and a 3.3V FPGA?

Yes - the 74LCXH245WM supports 5V-tolerant OE and T/R control inputs while operating at VCC = 3.3V, allowing direct connection to 5V GPIOs without level shifters. Its I/Os are not 5V-tolerant, so A/B-side data lines must remain within 0–VCC (0–3.3V). The 74LCXH245WM thus serves as a safe, low-skew directional bridge between 5V control logic and 3.3V data domains.

What is the maximum operating frequency supported by the 74LCXH245WM in a typical bus application?

The 74LCXH245WM does not specify a maximum clock frequency, but its 7.0 ns max propagation delay (tPHL/tPLH) at VCC = 3.3V and CL = 50 pF implies reliable operation in synchronous buses up to ~70 MHz (assuming 50% duty cycle and sufficient setup/hold margins). For the 74LCXH245WM, actual achievable frequency depends on load capacitance, trace length, and driving strength - validated per application.

Does the 74LCXH245WM require decoupling capacitors, and if so, what value is recommended?

Yes - the 74LCXH245WM requires a minimum 0.1 µF ceramic decoupling capacitor placed as close as possible (within 1 cm) to the VCC pin (pin 20) and GND pin (pin 10). Additional bulk capacitance (e.g., 4.7 µF tantalum) may be added near the power entry point for systems with dynamic current demands. This ensures stable VCC during fast output transitions and minimizes noise coupling into the 74LCXH245WM's sensitive bushold circuitry.

Is the 74LCXH245WM pin-compatible with other members of the LCXH family such as the 74LCXH16245?

No - the 74LCXH245WM is an 8-bit device in a 20-pin SOIC package, whereas the 74LCXH16245 is a 16-bit transceiver in a 48-pin TSSOP package. They share functional architecture (bushold, OE/T/R control, 2.3–3.6V operation) but differ in pin count, I/O count, and physical layout. The 74LCXH245WM has no pin-to-pin compatibility with wider or narrower variants; replacement requires PCB redesign.