Texas Instruments SN74LVC16646ADL

Overview

SN74LVC16646ADL from Texas Instruments is a 16-bit bus transceiver and register with 3-state outputs, designed for 1.65 V to 3.6 V operation. It supports mixed-mode signal operation (5-V inputs with 3.3-V VCC), features Ioff partial-power-down capability, and delivers 5.2 ns max propagation delay in transparent mode at 3.3 V - used in high-speed bidirectional data buffering between processor buses and peripheral subsystems.

For engineers reviewing the SN74LVC16646ADL datasheet, SN74LVC16646ADL pinout, SN74LVC16646ADL application, or SN74LVC16646ADL equivalent, key selection criteria include dual 8-bit register-controlled bus directionality, 56-pin SSOP (DL) package compatibility, 3.3-V/5-V level translation support, and guaranteed Ioff protection during power sequencing.

Technical Context

The SN74LVC16646ADL integrates two independent 8-bit transceiver/register blocks (A/B sides), each with dedicated clock (CLKAB/CLKBA), direction (DIR), output-enable (OE), and select (SAB/SBA) controls. Its D-type flip-flop registers capture data on low-to-high clock transitions, enabling synchronized storage and multiplexed real-time or registered data routing.

It implements glitch-free select logic to eliminate decoding transients during transitions between stored and transparent data paths. The device fully supports partial-power-down via Ioff, disabling outputs when VCC = 0 while allowing input signals up to 5.5 V without backflow current - critical for hot-swap and mixed-voltage system interoperability.

Key Specifications

Pinout & Package

SN74LVC16646ADL uses a 56-pin Shrink Small Outline Package (SSOP-DL), 13.9 mm × 7.4 mm body, 0.5 mm pitch, 1.2 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16646ADL, SN74LVC16245ADL omits register functionality entirely - limiting use to simple bus buffering - while SN74ALVC16646DL retains full feature parity but adds enhanced drive capability for marginal interconnects.

Availability

SN74LVC16646ADL is available at Aetrix Electronics and suitable for processor-peripheral bridging, hot-swappable module interfaces, and memory expansion subsystems requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for SN74LVC16646ADL 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 SN74LVC16646ADL belongs to TI's Widebus™ family of high-speed, low-voltage logic devices engineered for robust bidirectional data management in mixed-voltage digital systems.

FAQ

What is the maximum clock frequency supported by SN74LVC16646ADL?

The SN74LVC16646ADL supports a maximum clock frequency of 150 MHz at VCC = 3.3 V, as specified in the timing characteristics table. This applies to both CLKAB and CLKBA inputs under recommended operating conditions (TA = –40°C to 85°C). At lower VCC values (e.g., 1.8 V), the max clock rate reduces to 85 MHz. The device maintains full functionality across its entire 1.65–3.6 V supply range, with timing parameters derated accordingly.

Does SN74LVC16646ADL support 5-V tolerant inputs when powered at 1.8 V?

Yes, SN74LVC16646ADL supports input voltages up to 5.5 V regardless of VCC level - including at minimum 1.65 V operation. This 5-V tolerance is explicitly guaranteed in the Absolute Maximum Ratings and Recommended Operating Conditions tables. Inputs remain functional and within specification even when VCC = 1.8 V, enabling seamless interfacing with higher-voltage legacy components without external translators.

How does the Ioff feature of SN74LVC16646ADL protect the system during power-down?

The Ioff feature in SN74LVC16646ADL disables all outputs when VCC = 0 V, limiting off-state current to ±10 µA even if input or output pins are driven to 5.5 V. This prevents damaging back-current flow through the device during partial power-down or hot-swap events. Critically, input circuitry remains active - allowing continued signal reception and storage - making SN74LVC16646ADL suitable for systems requiring controlled power sequencing and live insertion.

Can SN74LVC16646ADL operate as two independent 8-bit transceivers?

Yes, SN74LVC16646ADL is architecturally divided into two independent 8-bit sections (1x and 2x), each with dedicated DIR, OE, CLKAB/CLKBA, and SAB/SBA controls. These sections can be configured separately - for example, one bank in transparent mode while the other operates in registered mode - enabling flexible bus segmentation, asymmetric data flow, or independent clock domain bridging without cross-talk or shared timing constraints.

What is the pin-compatible replacement for SN74LVC16646ADL in TSSOP package?

The pin-compatible replacement for SN74LVC16646ADL in TSSOP package is SN74LVC16646ADGGR (56-pin DGG). It shares identical logic function, pinout, electrical specifications, and timing behavior - differing only in package type (TSSOP vs SSOP), reel quantity (2000 vs 1000), and thermal impedance (θJA = 64°C/W for DL vs 48°C/W for DGG). No PCB redesign is required when migrating between SN74LVC16646ADL and SN74LVC16646ADGGR.