Texas Instruments SN74F543DBLE

Overview

SN74F543DBLE from Texas Instruments is an octal registered transceiver with 3-state outputs, implementing dual-directional data flow control via independent A-to-B and B-to-A latch-enable (LEAB/LEBA) and output-enable (OEAB/OEBA) inputs. It features A-side outputs rated for 24 mA sink current and B-side outputs rated for 64 mA sink current, operating across 4.5 V to 5.5 V supply at 0°C to 70°C. It is used in bus interface applications requiring temporary bidirectional data storage and controlled output isolation.

For engineers reviewing the SN74F543DBLE datasheet, SN74F543DBLE pinout, SN74F543DBLE application, or SN74F543DBLE equivalent, key selection criteria include its dual-latch architecture, asymmetric drive strength (24 mA vs. 64 mA), SSOP-24 package footprint, 3-state output timing (tPZH ≤ 10 ns), and compatibility with TTL-level logic families in legacy industrial control and memory expansion systems.

Technical Context

The SN74F543DBLE implements two independent sets of D-type latches - one for A-to-B and one for B-to-A data paths - each with dedicated CE, LE, and OE controls. Its logic operates under positive-logic conventions per ANSI/IEEE Std 91-1984, with latch transparency on LE low and storage on LE high-to-low transition.

It supports true 3-state output control per direction: OEAB low enables B outputs reflecting A-latch contents when CEAB is low; similarly, OEBA low enables A outputs reflecting B-latch contents when CEBA is low. Output disable states exhibit high-impedance with tPZL ≤ 12 ns and tPHZ ≤ 9 ns propagation delay to high-Z.

Key Specifications

Pinout & Package

SN74F543DBLE is housed in a 24-pin Shrink Small-Outline Package (SSOP-DB), measuring 8.2 mm × 7.4 mm with 0.65 mm lead pitch. The package is RoHS-compliant, moisture-sensitivity Level-1 rated, and designed for surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74F543DBLE, SN74F541DW omits bidirectional latching and B-side control entirely, while SN74ALS543N retains full functionality at reduced speed and power - making it a viable alternative where timing slack exists and thermal management is prioritized.

Availability

SN74F543DBLE is available at Aetrix Electronics and suitable for microprocessor bus interface, memory expansion module, industrial I/O expansion, and legacy test equipment backplane applications requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74F543DBLE 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74F543DBLE belongs to TI's 74F family of fast TTL logic devices, engineered for high-speed, low-latency data path control in legacy computing and industrial control systems.

FAQ

What is the maximum sink current supported by the B-side outputs of SN74F543DBLE?

The B-side outputs (B1–B8) of SN74F543DBLE are characterized to sink up to 64 mA per pin under recommended operating conditions (VCC = 4.5 V, TA = 0°C to 70°C). This rating is confirmed in the "recommended operating conditions" table and verified in the "electrical characteristics" section for VOL testing at IOL = 64 mA. Exceeding this current risks exceeding absolute maximum ratings and may compromise reliability or output voltage compliance.

Does SN74F543DBLE support operation at 3.3 V supply voltage?

No, SN74F543DBLE does not support 3.3 V operation. Its recommended supply voltage range is strictly 4.5 V to 5.5 V, and its input thresholds (VIH = 2.0 V, VIL = 0.8 V) and output drive characteristics are specified only within that range. Operation below 4.5 V violates the manufacturer's recommended conditions and may result in undefined logic states, increased propagation delay, or failure to meet VOL/VOL specifications. For 3.3 V systems, consider modern alternatives like SN74LVC245A.

What is the function of the CEAB and CEBA pins on SN74F543DBLE?

The CEAB (Chip Enable A-to-B) and CEBA (Chip Enable B-to-A) pins on SN74F543DBLE act as master enable controls for their respective data paths. CEAB must be low to allow data entry into the A latches or activation of the B outputs; CEBA must be low for B-latch loading or A-output activation. Both pins operate independently, enabling selective path isolation - for example, disabling A-to-B traffic while maintaining B-to-A communication in shared-bus arbitration schemes.

Is SN74F543DBLE pin-compatible with SN74F543DBR?

Yes, SN74F543DBLE and SN74F543DBR share identical pinout, package dimensions (SSOP-24, DB drawing), and electrical functionality. Both are marked "F543" and conform to the same TI mechanical and switching specifications. The suffix "LE" denotes a specific tape-and-reel variant (likely legacy packaging configuration), while "DBR" indicates standard production reel; no functional or pinout differences exist between them.

What is the minimum pulse width required for reliable LEAB or LEBA operation in SN74F543DBLE?

The minimum pulse width (tw) for LEAB or LEBA in SN74F543DBLE is 5 ns under all operating conditions (VCC = 4.5 V to 5.5 V, TA = 0°C to 70°C), as specified in the "timing requirements" table. This ensures reliable latch-edge detection and data capture. Shorter pulses risk metastability or incomplete latch triggering, especially near temperature extremes or voltage minima. System clock edges driving LE must meet or exceed this 5 ns width to guarantee deterministic register behavior in the SN74F543DBLE.