onsemi 74LCXH245MSAX

Overview

74LCXH245MSAX 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 bidirectional data flow controlled by T/R and OE inputs, ±24 mA output drive at 3.0V, 7.0 ns max propagation delay (VCC = 3.3V), and 5V-tolerant control inputs - enabling safe interface with legacy 5V logic in modern low-voltage systems.

For engineers reviewing the 74LCXH245MSAX datasheet, pinout, applications, or equivalent options, key selection considerations include bushold-enabled input stability without external resistors, 3-STATE bidirectional bus isolation, 20-pin SSOP package compatibility, and operation across industrial temperature range (−40°C to +85°C).

Technical Context

The 74LCXH245MSAX implements a dual-bus transceiver architecture with independent direction (T/R) and output enable (OE) control, supporting data flow either A→B or B→A under active control. Its bushold circuitry actively maintains valid logic levels on floating or unused inputs, eliminating external pull-up/pull-down components while ensuring noise immunity during bus contention or hot-swap transitions.

It operates within a 2.3V–3.6V VCC range with guaranteed DC and AC performance across the full industrial temperature range. All control inputs (T/R, OE) are 5V tolerant, allowing direct connection to higher-voltage controllers without level-shifting circuitry - critical for legacy-to-modern system integration.

Key Specifications

Pinout & Package

74LCXH245MSAX is housed in a 20-lead Shrink Small Outline Package (SSOP), EIAJ TYPE II, 5.3 mm wide, with 0.65 mm lead pitch and exposed pad not present. This compact surface-mount package supports high-density PCB layouts and automated assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR and 74ALVC16245PAG8, the 74LCXH245MSAX uniquely delivers bushold-enabled robustness in a compact 20-pin SSOP without sacrificing speed or drive strength - making it optimal for space-constrained, high-reliability 8-bit bus isolation tasks.

Availability

74LCXH245MSAX is available at Aetrix Electronics and suitable for industrial automation interfaces, embedded memory expansion, and hot-swappable module designs requiring stable component supply and long-term lifecycle support.

Supply support for 74LCXH245MSAX 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 sensor solutions for automotive, industrial, cloud computing, and consumer markets.

The 74LCXH245MSAX belongs to ON Semiconductor's legacy LCX logic family - engineered for low-voltage, high-speed bus interfacing in mixed-signal embedded systems where voltage translation, noise immunity, and board-space efficiency are critical.

FAQ

What is the maximum operating voltage for the control inputs of the 74LCXH245MSAX?

The 74LCXH245MSAX features 5V-tolerant control inputs (OE and T/R), allowing them to safely accept voltages from 0 V up to 5.5 V regardless of the VCC supply level (2.3V–3.6V). This tolerance enables direct interfacing with 5V microcontrollers or FPGAs without external level-shifting circuitry, simplifying system design and improving signal integrity in mixed-voltage environments. The 74LCXH245MSAX datasheet explicitly specifies this rating under Absolute Maximum Ratings and Recommended Operating Conditions.

Does the 74LCXH245MSAX require external pull-up resistors on its I/O pins?

No, the 74LCXH245MSAX does not require external pull-up or pull-down resistors on its A0–A7 or B0–B7 I/O pins due to integrated bushold circuitry. This feature actively maintains the last valid logic state on floating or unused inputs, eliminating risk of undefined states and reducing BOM count. The 74LCXH245MSAX bushold current specification (±75 µA min at VCC = 3.0V) confirms sufficient holding strength for reliable operation across temperature and voltage ranges.

What is the propagation delay of the 74LCXH245MSAX at 3.3V supply?

The 74LCXH245MSAX has a maximum propagation delay (tPHL/tPLH) of 7.0 ns when operated at VCC = 3.3V ± 0.3V, CL = 50 pF, and TA = −40°C to +85°C. This value is guaranteed across the full industrial temperature range and represents worst-case timing for both rising and falling edges. The 74LCXH245MSAX achieves this performance while maintaining low power consumption (10 µA ICC max), making it suitable for high-speed, low-power bus applications such as memory expansion and FPGA peripheral interfacing.

Which package type does the 74LCXH245MSAX use?

The 74LCXH245MSAX uses a 20-lead Shrink Small Outline Package (SSOP), designated as package number MSA20, with EIAJ TYPE II dimensions and a 5.3 mm body width. This surface-mount package features a 0.65 mm lead pitch and complies with JEDEC standards for automated assembly. The 74LCXH245MSAX SSOP footprint is distinct from SOIC (M20B) and TSSOP (MTC20) variants, requiring specific land pattern design per Fairchild/ON Semiconductor mechanical drawings.

Can the 74LCXH245MSAX operate at 2.5V supply voltage?

Yes, the 74LCXH245MSAX is fully specified to operate at 2.5V ± 0.2V supply voltage, with guaranteed AC performance including 8.4 ns max propagation delay (tPHL/tPLH) and 10.5 ns max output enable/disable times under CL = 30 pF conditions. Its 2.3V–3.6V VCC range makes the 74LCXH245MSAX compatible with both 2.5V and 3.3V system domains, supporting seamless integration into low-power embedded platforms where supply headroom is constrained.