Texas Instruments SN74ALVCH16646DLR

Overview

SN74ALVCH16646DLR from Texas Instruments is a 16-bit bus transceiver and register with 3-state outputs, designed for bidirectional data flow control between two 8-bit buses (A and B) in 1.65-V to 3.6-V systems. It supports real-time or registered data transfer, features dual clock inputs (CLKAB/CLKBA), independent direction (DIR) and output-enable (OE) controls per side, and operates across –40°C to 85°C for industrial applications.

For engineers reviewing the SN74ALVCH16646DLR datasheet, SN74ALVCH16646DLR pinout, SN74ALVCH16646DLR application, or SN74ALVCH16646DLR equivalent, this device delivers deterministic bus isolation, storage, and multiplexed data routing in memory expansion, FPGA I/O bridging, and multi-processor interconnect designs where voltage-level flexibility and bus-hold integrity are critical.

Technical Context

The SN74ALVCH16646DLR implements two independent 8-bit transceiver/register blocks, each with separate DIR, OE, CLKAB/CLKBA, and SAB/SBA controls - enabling simultaneous or staggered latching of A→B and B→A data on rising clock edges. Its EPIC™ submicron CMOS process ensures low propagation delay (≤5.6 ns at 3.3 V) and high noise immunity.

Bus-hold circuitry eliminates external pullup/pulldown resistors on all data inputs, while 3-state outputs support hot-swap compatibility and dynamic bus sharing. The device supports four fundamental bus-management modes: real-time transfer, stored-data transfer, dual-bus storage, and isolation - all configurable without glitch via dedicated select-control logic.

Key Specifications

Pinout & Package

SN74ALVCH16646DLR is packaged in a 56-pin SSOP (Shrink Small-Outline Package), DL variant, with 0.5-mm lead pitch, 11.4 mm × 7.9 mm body size, and 1.2 mm max height - optimized for space-constrained PCB layouts while maintaining hand-solderability and reflow compatibility.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit bus transceiver and register applications.

Compared with SN74ALVCH16646DLR, SN74ALVCH162245DLR omits clocked storage and select control - trading flexibility for simplicity - while SN74LVC16T245DGVR offers higher drive strength but sacrifices bus-hold and wide-voltage characterization, making SN74ALVCH16646DLR optimal for mixed-voltage, glitch-sensitive, or storage-dependent architectures.

Availability

SN74ALVCH16646DLR is available at Aetrix Electronics and suitable for industrial automation, FPGA prototyping, and embedded memory expansion requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for SN74ALVCH16646DLR 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 decades of expertise in high-reliability interface ICs and industrial-grade timing products.

The SN74ALVCH16646DLR belongs to TI's Widebus™ family of advanced bus-interface devices, engineered specifically for robust, low-glitch data routing in mixed-voltage, multi-processor, and FPGA-centric embedded systems.

FAQ

What is the recommended power-up sequence for SN74ALVCH16646DLR?

TI recommends tying OE inputs to VCC through a pullup resistor (value determined by driver sink capability) to ensure outputs remain in high-impedance state during power ramp-up. VCC must stabilize before applying clocks or data; no specific sequencing between VCC and GND is required, but all control inputs (DIR, OE, CLK, Sx) must be held static at valid logic levels before VCC reaches 1.5 V to prevent undefined behavior in SN74ALVCH16646DLR.

Does SN74ALVCH16646DLR support hot-swap operation?

Yes - SN74ALVCH16646DLR supports hot-swap due to its 3-state outputs, bus-hold inputs, and overvoltage-tolerant I/O structure (VI up to VCC + 0.5 V). When inserted into a live backplane, bus-hold maintains valid logic on floating inputs, and OE-controlled high-Z outputs prevent back-driving. However, VCC must be ramped within specification before asserting clocks or data to avoid metastability in SN74ALVCH16646DLR registers.

Can SN74ALVCH16646DLR operate reliably at 1.65 V VCC?

Yes - SN74ALVCH16646DLR is fully characterized down to 1.65 V, including timing (min fclock = 150 MHz), drive strength (IOL = 4 mA), and logic thresholds (VIH = 0.65 × VCC). At 1.65 V, setup/hold times increase slightly (tsu = 1.6 ns, th = 0.6 ns), but all functions - including bus-hold and 3-state control - remain guaranteed across –40°C to +85°C, making SN74ALVCH16646DLR suitable for ultra-low-power 1.8-V system designs.

How does the bus-hold feature work in SN74ALVCH16646DLR?

SN74ALVCH16646DLR integrates weak positive-feedback circuits on all A/B port inputs that detect and reinforce the last-valid logic state. When an input floats, bus-hold draws ±25 µA to ±75 µA (depending on VCC) to hold it near VIH or VIL - eliminating need for external resistors. This prevents oscillation or undefined states during idle periods, reset, or connector unplug events, directly enhancing system reliability in SN74ALVCH16646DLR-based interfaces.

What is the function of SAB and SBA pins in SN74ALVCH16646DLR?

In SN74ALVCH16646DLR, SAB (Select A→B) and SBA (Select B→A) control whether the output presents real-time (transparent) or stored (latched) data. For example, when SAB = L and DIR = H, real-time A data appears on B bus; when SAB = H, previously clocked A data is output. This hardware-select mechanism avoids timing glitches common in software-controlled multiplexers, ensuring clean transitions in SN74ALVCH16646DLR bus-management applications.