onsemi 74LVTH245MTCX

Overview

74LVTH245MTCX from ON Semiconductor is a low-voltage octal bidirectional transceiver with 3-STATE inputs/outputs, designed for bus interface between 3.3V logic and 5V TTL systems. It features bushold inputs (eliminating external pull-ups), ±32mA/64mA drive capability, 20-pin TSSOP package, and operates from 2.7V to 3.6V supply across –40°C to +85°C. It enables direction-controlled data flow in memory expansion and microcontroller peripheral buses.

For engineers reviewing the 74LVTH245MTCX datasheet, pinout, applications, or equivalent options, key selection criteria include bushold input support, 3.3V-to-5V level translation capability, 3-STATE bus isolation timing (tPZH ≤ 7.1 ns), and TSSOP-20 mechanical compatibility with high-density PCB layouts.

Technical Context

The 74LVTH245MTCX implements eight non-inverting bidirectional buffers controlled by two logic inputs: OE (active-HIGH output disable) and T/R (active-HIGH transmit, active-LOW receive). Data flows A→B when T/R = HIGH and OE = LOW; B→A when T/R = LOW and OE = LOW; both sides enter high-impedance state when OE = HIGH.

Bushold circuitry on all data inputs (A0–A7, B0–B7) maintains last-valid logic state without external biasing, supporting live insertion/extraction and reducing system component count. Power-up/down high-impedance behavior ensures glitch-free bus loading during supply transitions.

Key Specifications

Pinout & Package

74LVTH245MTCX uses a 20-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 4.4mm wide, with 0.65mm lead pitch and exposed pad not present. Pin 1 is marked by a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC245APWR and 74ALVC245MTCX, the 74LVTH245MTCX uniquely combines bushold inputs, 5V-tolerant I/O, and 3.3V-compatible drive strength-making it the only option among the three qualified for live-insertion 3.3V/5V bus bridging without external bias components.

Availability

74LVTH245MTCX is available at Aetrix Electronics and suitable for industrial PLC backplanes, microcontroller peripheral expansion, and legacy ISA bus adapters requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for 74LVTH245MTCX 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, and computing markets.

The 74LVTH245MTCX belongs to ON Semiconductor's legacy logic portfolio inherited from Fairchild, engineered specifically for robust 3.3V-to-5V bidirectional bus interfacing in industrial and embedded control systems.

FAQ

What is the bushold feature in the 74LVTH245MTCX and how does it affect circuit design?

The bushold feature in the 74LVTH245MTCX actively retains the last valid logic state on all data inputs (A0–A7, B0–B7) when left un-driven, eliminating the need for external pull-up or pull-down resistors. This reduces component count, saves PCB space, and improves reliability in systems with configurable or partially populated buses. For the 74LVTH245MTCX, bushold is intrinsic to the silicon design and requires no configuration-enabling immediate benefit in microcontroller GPIO expansion and hot-swap backplane applications.

Can the 74LVTH245MTCX safely interface a 3.3V FPGA with a 5V EEPROM without level-shifting circuitry?

Yes-the 74LVTH245MTCX supports direct 3.3V-to-5V bidirectional interfacing: its inputs tolerate up to 5.5V DC, and its outputs deliver TTL-compatible voltage levels (VOH ≥ 2.0V, VOL ≤ 0.55V at 64mA) that meet 5V EEPROM input thresholds. The 74LVTH245MTCX achieves this without external components due to its BiCMOS process and bushold-enhanced noise immunity, making it suitable for FPGA-to-EEPROM data/address bus translation in embedded boot loaders.

What is the maximum capacitive load the 74LVTH245MTCX can drive while maintaining guaranteed timing specs?

The 74LVTH245MTCX AC Electrical Characteristics are specified with CL = 50 pF and RL = 500 Ω, and propagation delays (tPLH/tPHL ≤ 4.0 ns) and 3-STATE timing (tPZH ≤ 7.1 ns) are guaranteed under those conditions. While the device can drive higher capacitance, timing margins degrade beyond 50 pF-so for designs requiring strict adherence to datasheet timing, total net capacitance-including trace, stub, and load-must be held at or below 50 pF. The 74LVTH245MTCX's 8 pF typical COUT helps minimize added load.

Does the 74LVTH245MTCX support hot-plug operation, and what design considerations enable this?

Yes-the 74LVTH245MTCX supports live insertion/extraction per its datasheet, enabled by three key features: power-up/down high-impedance behavior (outputs remain in 3-STATE during VCC ramp), bushold inputs (preventing floating nodes), and robust ESD protection (>2000V HBM). To implement hot-plug, ensure OE is held HIGH during insertion, use series resistors on control lines if needed, and verify that backplane connectors sequence VCC before signal lines-designs using the 74LVTH245MTCX have demonstrated reliable operation in modular PLC I/O carriers.

How does the 74LVTH245MTCX differ from the standard 74LVT245 in terms of functionality and application suitability?

The 74LVTH245MTCX includes bushold inputs, while the 74LVT245 does not-making the "H" variant essential where unused data lines must retain state without external biasing. Both share identical pinout, timing, drive strength, and voltage ratings. Therefore, the 74LVTH245MTCX is preferred in dynamically reconfigurable systems (e.g., FPGA mezzanine cards), whereas the 74LVT245 suffices in fixed-configuration designs with fully driven buses. The "H" suffix explicitly denotes bushold capability in the 74LVTH245MTCX.