NXP Semiconductors 74LVT543DB,112

Overview

74LVT543DB,112 from NXP Semiconductors (formerly Philips) is a 3.3V octal latched transceiver with dual enable and 3-state outputs, integrating latch and bus transceiver functions in one 24-pin SSOP device. It supports bidirectional data flow between two 8-bit buses (A0–A7 and B0–B7), provides ±64mA output drive, operates from –40°C to +85°C, and interfaces directly with 5V TTL systems - used in high-speed backplane and board-level bus bridging applications.

For engineers reviewing the 74LVT543DB,112 datasheet, 74LVT543DB,112 pinout, 74LVT543DB,112 application, or 74LVT543DB,112 equivalent, key selection criteria include independent A↔B latch/enable control, bus-hold inputs eliminating external pull-ups, power-up 3-state behavior, and guaranteed 2.3ns/3.0ns typical propagation delay at 3.3V with 50pF load.

Technical Context

The 74LVT543DB,112 implements two independent sets of D-type latches - one for A-to-B and one for B-to-A data paths - each with dedicated Latch Enable (LEAB/LEBA), Enable (EAB/EBA), and Output Enable (OEAB/OEBA) inputs. This architecture enables transparent, latched, or high-impedance operation per direction without cross-talk.

It uses BiCMOS technology for 3.3V VCC operation while maintaining TTL-compatible input thresholds (VIL = 0.8V, VIH = 2.0V) and 5V-tolerant I/Os. Bus-hold circuitry on all A-side inputs maintains valid logic states when unused, and live insertion/extraction is supported via controlled power-up reset and 3-state behavior.

Key Specifications

Pinout & Package

74LVT543DB,112 is housed in a 24-pin plastic shrink small outline package (SSOP), SOT340-1, 5.3 mm body width, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LVT543DB,112, the 74ALVT162245 offers double data width but forfeits integrated latching and bus-hold, increasing component count; the SN74LVC16245A reduces cost and power but eliminates 5V compatibility and robustness for industrial backplane use - making 74LVT543DB,112 uniquely suited for mixed-voltage, latch-critical, hot-swap-capable designs.

Availability

74LVT543DB,112 is available at Aetrix Electronics and suitable for backplane bridging, hot-swappable I/O modules, memory-mapped peripheral interfacing, and multi-processor shared bus applications requiring stable component supply across extended industrial temperature ranges.

Supply support for 74LVT543DB,112 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

NXP Semiconductors, formerly Philips Semiconductors, is a global leader in high-performance logic and interface ICs, delivering robust, automotive-qualified, and industrial-grade solutions since the 1980s.

The 74LVT543DB,112 belongs to NXP's LVT (Low-Voltage TTL) family - engineered specifically for 3.3V systems requiring seamless interoperability with legacy 5V logic, high-speed bus buffering, and reliable operation in harsh thermal and electrical environments.

FAQ

What is the maximum operating temperature range for the 74LVT543DB,112?

The 74LVT543DB,112 is rated for continuous operation from –40°C to +85°C ambient temperature, meeting industrial-grade reliability requirements. This range is validated per JEDEC JESD22-A104 and confirmed in the "Recommended Operating Conditions" section of the official Philips/NXP datasheet. The device maintains full AC/DC specifications across this range, including propagation delay, output drive, and bus-hold functionality - critical for deployment in uncontrolled environments like factory automation cabinets or outdoor telecom enclosures.

Does the 74LVT543DB,112 support live insertion into a powered 5V bus?

Yes, the 74LVT543DB,112 explicitly supports live insertion and extraction, as stated in its "Features" list and verified by its power-up 3-state behavior, bus-hold inputs, and 5V-tolerant I/O structure. During insertion, the outputs remain in high-impedance until VCC stabilizes, preventing bus contention; bus-hold on A-inputs avoids floating states; and ESD ratings (2000V HBM) protect against handling transients. This makes the 74LVT543DB,112 suitable for modular systems like PMC or XMC carriers where cards are added/removed under power.

Can the 74LVT543DB,112 interface directly with a 5V microcontroller without level shifters?

Yes, the 74LVT543DB,112 can interface directly with 5V microcontrollers: all inputs accept VI up to 7.0V (including 5V logic levels), and outputs drive 5V-tolerant loads with TTL-compatible VOH/VOL. Its VIL = 0.8V and VIH = 2.0V thresholds ensure reliable recognition of 5V signals while powered from 3.3V. However, note that the 74LVT543DB,112 itself must be supplied with 3.3V - it does not generate 5V outputs, but its outputs are safe to connect to 5V-biased buses due to internal clamp structures.

How does the bus-hold feature work on the 74LVT543DB,112 A-side inputs?

The bus-hold circuitry on the A0–A7 inputs of the 74LVT543DB,112 actively maintains the last-valid logic state using weak feedback transistors, drawing ±75 µA to ±150 µA (per pin) to overdrive external noise. This eliminates the need for external 10kΩ pull-up or pull-down resistors on unused or unterminated A-bus lines. The feature is always active when VCC is present and requires no enable signal - simplifying layout and improving noise immunity in sparse or intermittently driven bus segments.

What is the propagation delay difference between A→B and B→A paths in the 74LVT543DB,112?

The 74LVT543DB,112 exhibits symmetrical propagation delay: tPLH/tPHL is identical for An→Bn and Bn→An paths - 2.3ns/3.0ns typical (CL = 50pF, VCC = 3.3V). This symmetry is confirmed in the "Quick Reference Data" table and AC Characteristics section, where both directions share the same parameter symbol and limits. Designers can rely on matched timing for round-trip data transfer, critical for handshake protocols or echo-based diagnostics in full-duplex bus architectures.