onsemi 74LVTH543MTC

Overview

74LVTH543MTC from Fairchild Semiconductor is a low-voltage octal registered transceiver with 3-STATE outputs, designed for bidirectional data flow between 3.3V and 5V systems. It features dual D-type latch sets (A↔B), independent CE/LE/OE controls per direction, bushold inputs eliminating external pull-ups, and ±32 mA/64 mA drive capability. Used in bus interface logic for industrial backplanes and memory-mapped I/O.

For engineers reviewing the 74LVTH543MTC datasheet, pinout, applications, or equivalent options, key selection criteria include its 24-pin TSSOP package, 2.7–3.6V VCC operation, 3.3V-compatible TTL I/O, live insertion support, and power-up high-impedance behavior.

Technical Context

The 74LVTH543MTC implements two independent 8-bit registered paths-A-to-B and B-to-A-each controlled by dedicated Chip Enable (CEAB/CEBA), Latch Enable (LEAB/LEBA), and Output Enable (OEAB/OEBA) signals. Its BiCMOS fabrication enables ABT-class speed (tPLH/tPHL ≤ 4.8 ns at 3.3V) with LV logic power efficiency.

Bushold circuitry on all A0–A7 and B0–B7 I/O pins maintains valid logic states without external biasing, while power-up/down high-impedance prevents bus contention. The device supports live insertion/extraction and meets >500 mA latch-up immunity per JEDEC JESD78.

Key Specifications

Pinout & Package

74LVTH543MTC is housed in a 24-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 4.4 mm wide, with 0.65 mm lead pitch and exposed pad not present.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVT543PWR and 74ALVCH162244, the 74LVTH543MTC uniquely combines bushold inputs, full register independence per direction, and robust 64 mA sink drive - making it optimal for noise-sensitive, hot-swap-capable industrial bus interfaces requiring minimal external components.

Availability

74LVTH543MTC is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory-mapped I/O bridges, and hot-swappable module adapters requiring stable component supply and long-term lifecycle support.

Supply support for 74LVTH543MTC 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

Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and mixed-signal ICs, acquired by ON Semiconductor in 2016. Known for high-reliability logic, power, and interface solutions.

The 74LVTH543MTC belongs to Fairchild's LVTH (Low-Voltage TTL-High Speed) logic family, engineered for 3.3V systems needing TTL-compatible performance, bus integrity, and interoperability with 5V infrastructure.

FAQ

What voltage levels does the 74LVTH543MTC support on its I/O pins?

The 74LVTH543MTC accepts input voltages from 0 V to 5.5 V on all A0–A7 and B0–B7 pins while operating from a 2.7–3.6 V VCC supply. This 5V-tolerant capability allows direct interfacing with legacy 5V peripherals without external level shifters. Its output high/low voltage specs (VOH/VOL) are defined relative to VCC, ensuring compatibility with both 3.3V receivers and TTL-input devices.

Does the 74LVTH543MTC require external pull-up resistors on unused inputs?

No, the 74LVTH543MTC does not require external pull-up resistors on unused inputs because it integrates bushold circuitry on all 16 I/O pins (A0–A7 and B0–B7). This feature actively holds floating inputs at their last valid logic state using ±75 µA internal current, eliminating BOM cost and PCB routing overhead associated with discrete biasing networks.

Can the 74LVTH543MTC be used in hot-swap applications?

Yes, the 74LVTH543MTC supports live insertion and extraction due to its power-up/power-down high-impedance behavior. During power transitions, all outputs enter a high-Z state before internal logic stabilizes, preventing bus contention or signal glitches. This makes it suitable for modular telecom and industrial systems where field-replaceable units must be inserted or removed under power.

What is the maximum data rate supported by the 74LVTH543MTC?

The 74LVTH543MTC does not specify a maximum data rate in MHz but defines timing via propagation delays: tPLH/tPHL ≤ 4.8 ns (A/B to outputs) and tPZL/tPHZ ≤ 7.2 ns (OE-controlled enable/disable) at VCC = 2.7 V. Based on these values, reliable operation up to ~100 MHz is achievable in well-terminated, low-capacitance bus environments - consistent with standard 32-bit parallel bus timing budgets.

How does the latch enable (LE) function differ from chip enable (CE) in the 74LVTH543MTC?

In the 74LVTH543MTC, CEAB/CEBA must be LOW to activate the corresponding data path (A↔B), while LEAB/LEBA controls latching behavior: when LE is LOW, the latch is transparent (output follows input); on the LOW-to-HIGH transition of LE, data is captured and held. CE enables path access; LE determines whether data flows through or is stored - allowing independent control of data staging and bus access timing.