Texas Instruments SN74ALVCH16646DGVR

Overview

SN74ALVCH16646 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 integrates bus-hold circuitry to eliminate external pullup/pulldown resistors. It is used in high-density logic interfacing, such as memory expansion and processor-to-peripheral bridging in industrial controllers.

For engineers reviewing the SN74ALVCH16646 datasheet, SN74ALVCH16646 pinout, SN74ALVCH16646 application, or SN74ALVCH16646 equivalent, key selection considerations include its 56-pin TVSOP (DGV) package, dual 8-bit register/transceiver architecture, 150-MHz maximum clock frequency, bus-hold input retention, and -40°C to 85°C industrial temperature range.

Technical Context

The SN74ALVCH16646 implements two independent 8-bit register-controlled transceivers sharing common control logic: each side (A↔B) has dedicated DIR, OE, SAB/SBA, and CLKAB/CLKBA inputs. Data latching occurs on low-to-high clock transitions, enabling synchronous storage of A- or B-bus data before forwarding.

Its bus-hold circuitry actively maintains valid logic levels on floating inputs without external components, and its 3-state outputs support hot-swap and bus-isolation modes. The device operates across a wide VCC range (1.65 V–3.6 V), making it suitable for mixed-voltage system interconnects where voltage translation is managed externally.

Key Specifications

Pinout & Package

SN74ALVCH16646 is packaged in a 56-pin Thin Very Small-Outline Package (TVSOP, DGV), 11.4 mm × 4.4 mm × 1.2 mm max height, JEDEC MO-194 compliant, with gull-wing leads and pin 1 quadrant Q1 orientation in tape-and-reel delivery.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ALVCH16646, SN74ALVCH162245DGVR omits clocked registration and select logic-reducing latency but eliminating data staging-while SN74LVC16646DGVR trades bus-hold for higher drive strength and lacks integrated input retention, requiring layout-level biasing.

Availability

SN74ALVCH16646 is available at Aetrix Electronics and suitable for industrial PLC backplanes, memory expansion bridges, FPGA-to-ASIC protocol adapters, and legacy microprocessor bus isolators requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74ALVCH16646 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 for industrial and automotive markets.

The SN74ALVCH16646 belongs to TI's Widebus™ family of advanced CMOS bus-interface devices, engineered for low-voltage, high-speed, noise-tolerant data transfer in space-constrained industrial and computing systems.

FAQ

What is the recommended power-up sequence for SN74ALVCH16646?

TI recommends tying OE inputs to VCC through a pullup resistor (minimum value determined by driver sink capability) to ensure outputs remain in high-impedance during power ramp-up. VCC must stabilize before applying clocks or data. The SN74ALVCH16646 does not require specific sequencing between DIR, SAB, or CLKAB inputs, but all control inputs should be driven to valid logic levels before enabling outputs. This prevents bus contention and ensures deterministic register initialization.

Does SN74ALVCH16646 support mixed-voltage operation between A and B buses?

No - the SN74ALVCH16646 uses a single VCC supply for all I/Os and internal logic. Both A and B buses operate at the same VCC voltage (1.65 V–3.6 V). Voltage translation between disparate logic families must be handled externally using dedicated level translators; the SN74ALVCH16646 itself provides no built-in level-shifting functionality.

How does bus-hold functionality work on SN74ALVCH16646, and can it be disabled?

Bus-hold circuitry on the SN74ALVCH16646 is internal and always active on all A and B data inputs - it cannot be disabled. It applies weak feedback to retain the last-valid logic state when inputs float, drawing ±75 µA at 3.0 V. This eliminates external biasing but adds slight input capacitance (Cio = 8.5 pF). No configuration register or pin disables this feature; it is inherent to the ALVCH process.

What is the maximum data rate achievable using SN74ALVCH16646 in registered mode?

In registered mode, the SN74ALVCH16646 supports up to 150 MHz clock frequency (per CLKAB/CLKBA), enabling a theoretical maximum data throughput of 1.2 Gbps across its 16-bit bus (150 MHz × 16 bits). Real-world sustained rate depends on setup/hold timing margins, load capacitance, and PCB routing - TI specifies tsu = 1.4 ns and th = 0.7 ns at VCC = 2.7 V, allowing reliable operation at ≤125 MHz in typical layouts.

Can SN74ALVCH16646 be used as a single 16-bit transceiver, or is it limited to two 8-bit channels?

The SN74ALVCH16646 can be configured flexibly: as two independent 8-bit transceivers (using 1DIR/1OE/1CLKAB etc. for A1–A8 ↔ B1–B8, and 2DIR/2OE/2CLKAB for A9–A16 ↔ B9–B16), or as one unified 16-bit transceiver by synchronizing control signals across both sides. Its pinout and logic diagram confirm full 16-bit data path capability - the "two 8-bit" description reflects functional partitioning, not architectural limitation.