onsemi 74LCX16543MTDX

Overview

74LCX16543 from ON Semiconductor (formerly Fairchild) is a low-voltage 16-bit registered transceiver with independent A-to-B and B-to-A data paths, 5V-tolerant I/Os, 2.3–3.6V V_CC operation, 5.2 ns max propagation delay at 3.3V, and ±24 mA output drive-used in voltage-level bridging between 3.3V logic and legacy 5V buses in industrial backplanes and memory interface subsystems.

For engineers reviewing the 74LCX16543 datasheet, pinout, applications, or equivalent options, key selection considerations include bidirectional latch control per byte, 3-STATE output enable independence, 5V tolerance without external level shifters, and compatibility with 2.5V/3.3V system rails while interfacing to 5V peripherals.

Technical Context

The 74LCX16543 implements two independent 8-bit registered transceiver blocks, each with separate CE, LE, and OE controls for direction, latching, and output gating-enabling simultaneous or staggered A↔B data transfers. Its dual-latch architecture supports transparent mode (LE low) and storage mode (LE rising edge), decoupling input sampling from output timing.

It uses advanced CMOS process technology to achieve sub-6 ns propagation delay at 3.3V while maintaining <20 µA quiescent ICC and supporting live insertion via power-down high-impedance I/O states. All inputs and outputs tolerate 0–5.5V regardless of V_CC, enabling safe interfacing across mixed-voltage domains without clamping diodes or external protection.

Key Specifications

Pinout & Package

74LCX16543MTDX is supplied in a 56-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 6.1 mm wide, with 0.5 mm lead pitch and exposed pad not present. Pin numbering follows standard TSSOP convention starting at pin 1 (top-left corner, dot-marked).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LCX16543MTDX, the 74ALVC16543DGGR offers superior speed but sacrifices 5V tolerance, while the SN74LVC16543DGGR matches voltage tolerance and package but trades 0.9 ns of propagation delay for broader manufacturer support and extended lifecycle assurance.

Availability

74LCX16543MTDX is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory subsystem bridges, test equipment data capture, and legacy peripheral adapters requiring stable component supply across extended production cycles.

Supply support for 74LCX16543MTDX 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 (formerly Fairchild Semiconductor) is a global semiconductor supplier specializing in power management, analog, sensor, and logic solutions for automotive, industrial, and cloud infrastructure markets.

The 74LCX logic family was designed for low-voltage, high-speed interoperability between emerging 2.5V/3.3V systems and legacy 5V environments-emphasizing voltage tolerance, noise immunity, and live-insertion robustness.

FAQ

What is the recommended power-up sequence for 74LCX16543MTDX to avoid bus contention?

During power-up, tie OEABn and OEBAn to V_CC via ≥10 kΩ pull-up resistors to ensure outputs remain in high-impedance until system initialization completes. The 74LCX16543MTDX enters power-down high-Z state automatically when V_CC is below 1.5V, but explicit OE control prevents glitches during brown-out conditions. Do not leave OE pins floating.

Can 74LCX16543MTDX operate reliably at 2.5V V_CC with 5V inputs applied?

Yes, the 74LCX16543MTDX supports 2.5V V_CC operation with full 0–5.5V input voltage tolerance per its DC Electrical Characteristics table. At V_CC = 2.5V, VOH is guaranteed ≥1.8V and VOL ≤0.6V under 8 mA load-meeting LVTTL thresholds. Inputs remain valid up to 5.5V regardless of V_CC level.

Does 74LCX16543MTDX support true bidirectional concurrent data flow?

No, the 74LCX16543MTDX does not support simultaneous A→B and B→A transfers on the same pins. It provides independent control for each direction, but A0–A15 and B0–B15 are shared I/Os-data flows either A→B or B→A per transaction, controlled by CEABn/CEBAn activation. Concurrent use would cause bus contention.

What is the minimum pulse width requirement for LEABn in 74LCX16543MTDX?

The 74LCX16543MTDX requires a minimum LEABn (or LEBAn) low pulse width of 3.0 ns at V_CC = 2.5V and 3.3V, per AC Electrical Characteristics. This ensures reliable latch capture; shorter pulses may result in metastability or incomplete data registration. Use monostable circuits or FPGA timing constraints to guarantee compliance.

Is 74LCX16543MTDX pin-compatible with other 56-pin TSSOP registered transceivers?

The 74LCX16543MTDX has a unique pinout optimized for dual-byte control (separate CE/LE/OE per direction) and is not pin-compatible with generic 16-bit transceivers like 74LVC16245 or 74ALVCH162244. Always verify pin mapping against the official connection diagram-not package outline-before PCB reuse.