Texas Instruments SN74LVCH16543ADLR

Overview

SN74LVCH16543ADLR from Texas Instruments is a 16-bit registered transceiver with 3-state outputs, designed for bidirectional data flow between two 8-bit buses or as a single 16-bit path. It operates from 1.65 V to 3.6 V, supports 5.5-V-tolerant inputs, delivers 5.4 ns max propagation delay at 3.3 V, and features bus-hold circuitry and Ioff partial-power-down protection - used in mixed-voltage memory interface and FPGA-to-ASIC data bridging applications.

For engineers reviewing the SN74LVCH16543ADLR datasheet, SN74LVCH16543ADLR pinout, SN74LVCH16543ADLR application, or SN74LVCH16543ADLR equivalent, key selection criteria include its dual 8-bit latch-enable control, 3.3-V/5-V mixed-mode signal compatibility, 56-pin SSOP package, and guaranteed 250 mA latch-up immunity per JESD 17.

Technical Context

The SN74LVCH16543ADLR implements two independent 8-bit registered transceiver sections (A↔B), each with dedicated CEAB/CEBA, LEAB/LEBA, and OEAB/OEBA controls enabling asynchronous, directionally isolated data latching and output gating. Its logic diagram confirms separate A-side and B-side input registers feeding independent 3-state output buffers.

It uses Widebus™ CMOS technology with bus-hold on all A/B data pins (eliminating external pull resistors) and Ioff circuitry that disables outputs during power-down to prevent backflow current - critical for hot-swap and partial-power-down systems operating across 1.65–3.6 V supply rails.

Key Specifications

Pinout & Package

SN74LVCH16543ADLR is packaged in a 56-pin SSOP (DL) with 0.5-mm pitch, 13.9 mm × 7.9 mm body size, and 1.2 mm max height - compatible with standard surface-mount reflow profiles (MSL Level-1, 260°C peak).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16245ADLR and SN74AVC16T245DGGR, the SN74LVCH16543ADLR uniquely combines 5-V-tolerant inputs, integrated bus-hold, Ioff protection, and dual 8-bit registration - making it the only choice for robust, latch-based 3.3-V/5-V bridging without external support components.

Availability

SN74LVCH16543ADLR is available at Aetrix Electronics and suitable for memory interface bridges, FPGA-to-ASIC links, industrial PLC backplanes, and test equipment bus extenders requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74LVCH16543ADLR 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The SN74LVCH16543ADLR belongs to TI's Widebus™ family of high-speed, low-voltage CMOS logic devices - engineered specifically for reliable, low-noise, mixed-voltage parallel bus interfacing in demanding embedded systems.

FAQ

What is the maximum clock frequency supported by SN74LVCH16543ADLR?

The SN74LVCH16543ADLR does not contain an internal clock; it is a registered transceiver whose timing depends on external control signals (LE, OE, CE). With a maximum propagation delay (tpd) of 5.4 ns at 3.3 V, it supports data rates up to approximately 185 MHz in systems where setup/hold margins and board layout allow. The actual usable frequency must be validated against the specific timing budget of the host design using the device's published tsu/th values.

Does SN74LVCH16543ADLR support hot-swap operation?

Yes, SN74LVCH16543ADLR supports hot-swap operation via its Ioff feature, which disables outputs when VCC = 0 V to prevent current backflow. Its 5.5-V-tolerant inputs also allow safe connection to live 5-V buses before VCC is applied. However, OE pins should be tied to VCC through a pullup resistor during power-up to guarantee high-impedance outputs until firmware initializes control logic - a requirement explicitly stated in the datasheet for robust hot-swap behavior.

Can SN74LVCH16543ADLR be used as a level shifter between 1.8-V and 3.3-V systems?

No - SN74LVCH16543ADLR is not a dual-supply level shifter. It operates from a single VCC (1.65–3.6 V) and accepts inputs up to 5.5 V, but its outputs swing between GND and VCC. To translate from 1.8-V logic to 3.3-V logic, VCC must be set to 3.3 V, and the 1.8-V source must meet the device's VIH/VIL thresholds at that VCC. For true bidirectional 1.8-V ↔ 3.3-V translation, a dual-supply device like SN74AVC16T245 is required.

How does bus-hold functionality work on SN74LVCH16543ADLR?

Bus-hold on SN74LVCH16543ADLR is an internal weak-latch circuit on every A- and B-side data input pin. When an input floats, the bus-hold circuit detects its last valid logic state and applies just enough current (±45 µA typical at 2.3 V) to maintain that state - eliminating need for external pullup/pulldown resistors. This feature remains active regardless of OE or DIR state and cannot be disabled, simplifying PCB design for unterminated or sparsely loaded buses.

What is the recommended power-up sequence for SN74LVCH16543ADLR?

The recommended power-up sequence for SN74LVCH16543ADLR is to apply VCC before asserting any control signals (OE, LE, CE). To ensure outputs remain in high-impedance during power-up, OEAB and OEBA pins must be held high (via pullup to VCC) until firmware configures them. TI specifies a minimum pullup resistor value based on driver sink capability; for most microcontrollers, a 10-kΩ resistor suffices. Failure to follow this sequence may cause output contention or glitching on connected buses.