onsemi 74LVTH16646MEAX

Overview

74LVTH16646MEAX from ON Semiconductor is a low-voltage 16-bit registered transceiver with 3-STATE outputs, bushold inputs, and dual-directional data flow control via DIR pins. It operates at 2.7–3.6 V, supports 5V-tolerant I/O, delivers ±32 mA/±64 mA drive strength, and features CPAB/CPBA clocked register loading for A/B bus storage. It is used in high-speed backplane and memory interface applications requiring glitch-free bus isolation and live insertion.

For engineers reviewing the 74LVTH16646MEAX datasheet, pinout, applications, or equivalent options, key selection criteria include bushold-enabled input retention, 150 MHz maximum clock frequency, 3.3 V supply compatibility with 5 V I/O tolerance, and SSOP-56 package suitability for space-constrained board layouts.

Technical Context

The 74LVTH16646MEAX implements two independent 8-bit register banks (A and B) with separate clock (CPAB/CPBA), select (SAB/SBA), and direction (DIR1/DIR2) controls. Data can be transferred in real-time (transparent mode) or stored-and-forwarded (registered mode), enabling flexible bus multiplexing and timing isolation between subsystems.

Its bushold circuitry actively maintains logic state on un-driven A/B data pins without external pull-ups-critical for hot-swap and partial-bus-enable scenarios. The device meets JEDEC JED78 latch-up immunity and exceeds 2000 V HBM ESD rating, supporting robust operation in industrial backplanes and telecom line cards.

Key Specifications

Pinout & Package

74LVTH16646MEAX is housed in a 56-lead Shrink Small Outline Package (SSOP), JEDEC MO-118 compliant, 0.300" wide, with 0.025" pitch. Package dimensions: 18.4 mm × 7.5 mm × 2.4 mm (L × W × H).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16646ADGGR and 74ALVCH16646GR, the 74LVTH16646MEAX uniquely combines bushold-enabled input stability, 5 V-tolerant I/O, and SSOP-56 mechanical compatibility-making it the preferred choice for industrial backplanes and legacy-system upgrades where reliability under partial enable conditions is critical.

Availability

74LVTH16646MEAX is available at Aetrix Electronics and suitable for high-speed backplane interfaces, memory buffer subsystems, industrial PLC I/O modules, and telecom line card data mux applications requiring stable component supply and long-term lifecycle support.

Supply support for 74LVTH16646MEAX 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

ON Semiconductor is a global semiconductor manufacturer specializing in energy-efficient power, analog, sensor, and logic solutions for automotive, industrial, cloud, and communications markets.

The 74LVTH16646MEAX belongs to ON Semiconductor's legacy logic portfolio-designed specifically for robust, mixed-voltage bus interfacing in industrial and telecom infrastructure where reliability, ESD resilience, and hot-swap readiness are non-negotiable.

FAQ

What is the function of the bushold feature in the 74LVTH16646MEAX?

The bushold feature in the 74LVTH16646MEAX actively retains the last valid logic state on any un-driven A0–A15 or B0–B15 input pin, eliminating the need for external pull-up or pull-down resistors. This ensures deterministic behavior during partial bus enable, hot-insertion, or tri-state transitions-critical for system stability in modular backplane designs. The 74LVTH16646MEAX specifies ±75 µA minimum drive current at VI = 0.8 V/2.0 V to guarantee reliable state hold.

Does the 74LVTH16646MEAX support 5 V logic levels on its I/O pins?

Yes, the 74LVTH16646MEAX supports 5 V-tolerant inputs: its VI rating extends to 5.5 V while operating from a 2.7–3.6 V VCC supply. This allows direct connection to 5 V TTL or LVTTL outputs without level-shifting circuitry. However, output voltage swing remains rail-to-rail relative to VCC (not 5 V), so driving 5 V loads requires external termination or compatible receiver thresholds. The 74LVTH16646MEAX datasheet confirms this in the Recommended Operating Conditions table.

What is the difference between transparent mode and stored mode in the 74LVTH16646MEAX?

In transparent mode (e.g., OE1 = L, DIR1 = H, SAB1 = L), data passes directly from A0–A7 to B0–B7 with minimal propagation delay (~1.0–4.6 ns). In stored mode (e.g., OE1 = L, DIR1 = H, SAB1 = H, CPAB1 ↑), data present at A0–A7 is latched into the A-register on the CPAB1 rising edge and then forwarded to B0–B7-introducing one clock-cycle latency but enabling synchronization across clock domains. The 74LVTH16646MEAX supports both modes simultaneously per byte group via independent control pins.

Can the 74LVTH16646MEAX be used in hot-swap applications?

Yes, the 74LVTH16646MEAX supports live insertion/extraction due to its power-up/power-down high-impedance outputs and bushold input retention. During power ramp-up or ramp-down, all outputs remain in high-Z until VCC stabilizes within specification, preventing bus contention. Its ±100 µA power-up/down leakage (IPU/PD) and JEDEC JED78 latch-up compliance further ensure robustness in hot-swap carrier applications. This behavior is explicitly documented for the 74LVTH16646MEAX in the Functional Description section.

What package type does the 74LVTH16646MEAX use, and is it RoHS compliant?

The 74LVTH16646MEAX uses a 56-lead Shrink Small Outline Package (SSOP), JEDEC MO-118 compliant, marked as Package Number MS56A. It measures 18.4 mm × 7.5 mm × 2.4 mm with 0.025" lead pitch. As a Fairchild-integrated ON Semiconductor product released post-2001 and supplied in tape-and-reel format (denoted by suffix "X"), the 74LVTH16646MEAX meets RoHS Directive 2011/65/EU requirements-confirmed by ON Semiconductor's public compliance documentation and material declarations.