Texas Instruments SN74F543DBR

Overview

SN74F543DBR from Texas Instruments is an octal registered transceiver with dual-direction 3-state outputs, featuring independent A-to-B and B-to-A latch-enable (LEAB/LEBA) and output-enable (OEAB/OEBA) controls, 24 mA A-side sink capability, 64 mA B-side sink capability, and operation across 0°C to 70°C for bus interface applications in industrial control backplanes.

For engineers reviewing the SN74F543DBR datasheet, SN74F543DBR pinout, SN74F543DBR application, or SN74F543DBR equivalent, this page delivers verified functional architecture, timing parameters (tPLH/tPHL ≤ 8.5 ns), absolute maximum ratings (VCC up to 7 V), package-specific thermal and reflow data (SSOP-24, MSL Level-1), and direct alternative comparisons for legacy TTL bus interface design continuity.

Technical Context

The SN74F543DBR implements two independent octal D-type latch banks with separate CE/LE/OE controls per direction, enabling bidirectional data staging without contention. Its true 3-state outputs support hot-swap-capable bus arbitration via OE-driven high-impedance states on both A and B ports.

It operates strictly within 4.5–5.5 V supply range with TTL-compatible input thresholds (VIL = 0.8 V, VIH = 2.0 V) and delivers guaranteed low-level output currents of 24 mA (A-side) and 64 mA (B-side) at VOL ≤ 0.55 V, meeting legacy F-series TTL drive requirements for backplane loading.

Key Specifications

Pinout & Package

SN74F543DBR uses a 24-pin Shrink Small-Outline Package (SSOP-DB) with 0.65 mm lead pitch, 5.3 mm width, and JEDEC MO-150 compliance. Pin 1 is located in Quadrant Q1 per tape-and-reel orientation.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74F543DBR, SN74F541DBR eliminates bidirectional control overhead but sacrifices system flexibility, while SN74LS543DW offers footprint compatibility at the cost of 3× slower timing and reduced drive-making SN74F543DBR optimal for performance-critical or space-constrained F-series upgrades.

Availability

SN74F543DBR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy bus expansion systems, and microcontroller peripheral hubs requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74F543DBR 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic solutions, with over 90 years of innovation in industrial, automotive, and communications markets.

The SN74F543DBR belongs to TI's 74F logic family, designed specifically to deliver higher speed and improved noise immunity over LS-TTL while maintaining pin compatibility and 5 V operation for industrial control and computing infrastructure.

FAQ

What is the maximum clock frequency supported by SN74F543DBR?

The SN74F543DBR does not contain an internal clock; it is an edge-triggered latch-based transceiver. Its usable data rate depends on external timing: with tPLH/tPHL ≤ 8.5 ns and setup/hold times of 3.5 ns, it supports reliable 120 MHz toggle rates on 5 V buses when driven by clean, well-timed LE/OE signals. The SN74F543DBR is not rated for continuous clocked operation like a shift register.

Can SN74F543DBR operate at 3.3 V?

No, SN74F543DBR is specified only for 4.5 V to 5.5 V operation per its recommended conditions. At 3.3 V, VIH (2.0 V) and VOL (≤0.55 V) margins collapse, and output drive falls outside specification. Using SN74F543DBR at 3.3 V risks unreliable switching, increased static current, and potential damage due to underspecified internal biasing - it must be used at 5 V nominal.

Does SN74F543DBR support hot-swap insertion?

Yes, SN74F543DBR supports controlled hot-swap via its 3-state outputs: when OEAB and OEBA are held high before power-up, both A and B ports remain in high-impedance state, preventing bus contention. Its absolute maximum rating allows VCC ramp-up with inputs at 0 V, and the SSOP-24 package's MSL Level-1 rating permits standard reflow without preconditioning - essential for field-replaceable module designs using SN74F543DBR.

What is the difference between CEAB and LEAB on SN74F543DBR?

CEAB (Chip Enable A-to-B) is a gating input that must be low to permit any A→B data flow or B-output activation; LEAB (Latch Enable A-to-B) controls the transparency/storage mode of the A-to-B latches. With CEAB low and LEAB low, A inputs pass through to B latches; a rising edge on LEAB captures and holds that data. Both signals are required for functional A→B operation - CEAB enables the path, LEAB controls latching - a distinction critical for synchronous bus protocols using SN74F543DBR.

Is SN74F543DBR RoHS compliant?

Yes, SN74F543DBR is RoHS compliant, as confirmed by Texas Instruments' packaging documentation: it carries "Yes" in the RoHS column, uses NiPdAu (NIPDAU) lead finish, and meets EU Directive 2011/65/EU requirements. The device is marked "F543" and shipped in tape-and-reel format (2000 pcs/reel), with full compliance documentation available via TI's Quality & Environmental page for SN74F543DBR.