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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

onsemi 74LVTH16646MTDX

Name: 74LVTH16646MTDX
Brand: onsemi
SKU: 74LVTH16646MTDX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74LVTH16646MTDX

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 56-TFSOP (0.240", 6.10mm Width)

Datasheet:: 74LVTH16646MTDX.pdf

Description:: IC TXRX NON-INVERT 3.6V 56TSSOP

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Product details

Overview

74LVTH16646MTDX 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 stored-mode bus management in high-speed digital systems.

For engineers reviewing the 74LVTH16646MTDX datasheet, pinout, applications, or equivalent options, this device is selected for bidirectional 3.3V bus interfacing with TTL-level compatibility, real-time or registered data transfer, and robust hot-swap capability in memory expansion, FPGA I/O bridging, and backplane interface designs.

Technical Context

The 74LVTH16646MTDX implements two independent 8-bit transceiver/register sections (A0–A7/B0–B7 and A8–A15/B8–B15), each with dedicated DIR, OE, CPAB/CPBA, and SAB/SBA controls. Data flows either transparently (real-time) or from internal registers (stored mode), enabling time-multiplexed bus sharing and latch-based synchronization.

Bushold circuitry on all data I/O pins (A0–A15, B0–B15) maintains valid logic states without external pull-ups when unused, reducing BOM count and PCB routing complexity. Its BiCMOS process achieves 150 MHz maximum clock frequency with propagation delays as low as 1.0 ns (tPLH/tPHL) under 3.3 V operation.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	2.7–3.6 V - Enables direct integration into 3.3V core logic domains while maintaining compatibility with 5V peripheral interfaces.
Max Clock Frequency	150 MHz - Supports high-throughput synchronous data transfers between buses without external timing constraints.
Output Drive	−32 mA / +64 mA - Ensures reliable signal integrity across loaded backplanes or multi-drop bus topologies.
Propagation Delay	1.0–5.4 ns - Guarantees sub-6 ns timing margins for 100+ MHz system clocks in registered or transparent modes.
Bushold Input	Yes - Eliminates need for 32 external pull-up resistors on A/B data lines, simplifying layout and reducing power leakage risk.
Operating Temperature	−40°C to +85°C - Qualified for industrial-grade embedded systems including telecom line cards and programmable logic controllers.
I/O Voltage Tolerance	0–5.5 V - Allows safe connection to legacy 5V logic without level shifters or clamping diodes.

Pinout & Package

74LVTH16646MTDX is housed in a 56-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 6.1 mm wide, with 0.5 mm lead pitch and exposed thermal pad (not electrically connected). This package supports automated surface-mount assembly and provides enhanced thermal dissipation over standard SOIC.

Pin/Terminal	Circuit Role	Design Meaning
A0–A15	Data Register A I/O	Bidirectional port: inputs load A register on CPAB edge; outputs reflect A register or real-time A-bus data when enabled.
B0–B15	Data Register B I/O	Bidirectional port: inputs load B register on CPBA edge; outputs reflect B register or real-time B-bus data when enabled.
CPAB, CPBA	Register Clock Inputs	LOW-to-HIGH transitions load data from A or B bus into respective registers - enables synchronized capture of bus state.
DIR1, DIR2	Direction Control	Selects real-time data flow direction: DIR = HIGH → A→B; DIR = LOW → B→A - no latching required.
OE1, OE2	Output Enable	Active-low control per byte group: HIGH disables outputs (3-STATE), preserving bus integrity during arbitration or idle periods.
SAB1, SBA1, SAB2, SBA2	Mode Select	Configure each byte group for real-time transfer, register-to-bus output, or clocked register load - enables flexible multiplexing.

Key Features

Feature	Design Value
Bushold Inputs	Maintains stable logic levels on floating A/B pins without external biasing - reduces component count and board area in sparse-bus configurations.
Live Insertion Support	Power-up/down high-impedance behavior prevents bus contention during hot-plug events - essential for modular chassis and field-replaceable units.
Dual-Byte Control	Independent DIR/OE/SAB/SBA per 8-bit half enables asymmetric operation - e.g., A0–A7 in stored mode while A8–A15 operate transparently.
TTL-Compatible I/O	5V-tolerant inputs and 3.3V-compatible outputs allow seamless interconnection with legacy microcontrollers, ASICs, and FPGAs without voltage translation.
Latch-Up Immunity	Complies with JEDEC JED78 - ensures robustness against transient-induced parasitic thyristor activation in noisy industrial environments.

Applications

Memory Expansion Interface	FPGA I/O Bridging
Use Scenario: Expanding address/data bus width between a 32-bit microcontroller and parallel SRAM or Flash memory arrays. IC Role / Device Role / Timing Role: Registered transceiver synchronizing burst reads/writes across mismatched clock domains while isolating memory from CPU bus noise. Use Value: Enables deterministic 150 MHz data handshaking with zero wait-state cycles using internal register storage and precise 1.0 ns min tPLH timing.	Use Scenario: Interfacing a Xilinx Artix-7 FPGA's bank-1 I/O (3.3V) to an external 5V ADC or DAC subsystem. IC Role / Device Role / Timing Role: Level-shifting bidirectional data path with bushold protection for unconnected FPGA pins during configuration or partial reconfiguration. Use Value: Eliminates 32 discrete pull-up resistors and guarantees 5.5V-tolerant input safety - reducing BOM cost by $0.18/unit and improving layout density.
Industrial Backplane Bus	Modular PLC I/O Carrier
Use Scenario: Time-multiplexed communication between multiple I/O modules on a 16-bit parallel backplane in a DIN-rail mounted controller. IC Role / Device Role / Timing Role: Bus arbitrator and data register managing shared access to common memory-mapped registers across up to four slot positions. Use Value: Supports glitch-free hot insertion via power-up 3-STATE and enables deterministic read-modify-write sequences using CPAB/CPBA edge-triggered latching.	Use Scenario: Isolating and buffering analog/digital I/O signals between a central PLC CPU module and interchangeable I/O carrier boards. IC Role / Device Role / Timing Role: Direction-controlled signal repeater with independent enable per byte group, allowing selective activation of DI/DO or AI/AO banks. Use Value: Permits mixed-voltage operation (3.3V CPU, 5V sensors) and eliminates bus contention during module replacement - meeting IEC 61000-4-2 ESD immunity requirements.

Memory Expansion Interface

FPGA I/O Bridging

Use Scenario: Expanding address/data bus width between a 32-bit microcontroller and parallel SRAM or Flash memory arrays.

IC Role / Device Role / Timing Role: Registered transceiver synchronizing burst reads/writes across mismatched clock domains while isolating memory from CPU bus noise.

Use Value: Enables deterministic 150 MHz data handshaking with zero wait-state cycles using internal register storage and precise 1.0 ns min tPLH timing.

Use Scenario: Interfacing a Xilinx Artix-7 FPGA's bank-1 I/O (3.3V) to an external 5V ADC or DAC subsystem.

IC Role / Device Role / Timing Role: Level-shifting bidirectional data path with bushold protection for unconnected FPGA pins during configuration or partial reconfiguration.

Use Value: Eliminates 32 discrete pull-up resistors and guarantees 5.5V-tolerant input safety - reducing BOM cost by $0.18/unit and improving layout density.

Industrial Backplane Bus

Modular PLC I/O Carrier

Use Scenario: Time-multiplexed communication between multiple I/O modules on a 16-bit parallel backplane in a DIN-rail mounted controller.

IC Role / Device Role / Timing Role: Bus arbitrator and data register managing shared access to common memory-mapped registers across up to four slot positions.

Use Value: Supports glitch-free hot insertion via power-up 3-STATE and enables deterministic read-modify-write sequences using CPAB/CPBA edge-triggered latching.

Use Scenario: Isolating and buffering analog/digital I/O signals between a central PLC CPU module and interchangeable I/O carrier boards.

IC Role / Device Role / Timing Role: Direction-controlled signal repeater with independent enable per byte group, allowing selective activation of DI/DO or AI/AO banks.

Use Value: Permits mixed-voltage operation (3.3V CPU, 5V sensors) and eliminates bus contention during module replacement - meeting IEC 61000-4-2 ESD immunity requirements.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74LVC16646ADGGR	No bushold; CMOS-only process; lower drive (±24 mA); max fCLK = 100 MHz	Requires external pull-ups on unused I/O; unsuitable for hot-swap-critical systems	Preferred where cost sensitivity outweighs reliability requirements and board space allows pull-up resistors.
74ALVCH16646PAG	Higher VCC range (2.3–3.6 V); no bushold; 3.6V-tolerant I/O only (not 5V)	Limited to pure 3.3V systems; lacks 5V interface capability for legacy peripherals	Chosen when operating exclusively in low-voltage domains and maximum speed (160 MHz) is prioritized over interface flexibility.

Compared with SN74LVC16646ADGGR and 74ALVCH16646PAG, the 74LVTH16646MTDX uniquely combines 5V-tolerant I/O, bushold inputs, and 150 MHz performance - making it the only option supporting hot-pluggable 3.3V/5V mixed-signal backplanes without design compromises.

Availability

74LVTH16646MTDX is available at Aetrix Electronics and suitable for memory expansion interfaces, FPGA I/O bridging, and industrial backplane bus applications requiring stable component supply, long-term lifecycle assurance, and traceable sourcing for production programs.

Supply support for 74LVTH16646MTDX 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 management, signal processing, and logic solutions for automotive, industrial, and cloud infrastructure markets.

The 74LVTH16646MTDX belongs to ON Semiconductor's legacy LVT/LVTH logic family, engineered specifically for high-speed, low-voltage bidirectional bus interfacing in mixed-voltage embedded systems with stringent reliability and thermal constraints.

FAQ

What is the function of the CPAB and CPBA pins on the 74LVTH16646MTDX?

The CPAB and CPBA pins are clock pulse inputs that trigger LOW-to-HIGH edge-sensitive loading of data from the A-bus or B-bus into their respective internal registers. When CPAB goes HIGH, data present on A0–A15 is captured into the A register; similarly, CPBA loads B0–B15 into the B register. This enables synchronized, non-transparent data staging critical for burst transfers and bus arbitration in the 74LVTH16646MTDX.

Does the 74LVTH16646MTDX support hot-plug operation?

Yes, the 74LVTH16646MTDX supports live insertion and extraction due to its power-up/power-down high-impedance feature. During power transitions, all outputs enter 3-STATE before supply stabilization, preventing bus contention or signal corruption. This behavior is verified per JEDEC JESD78 latch-up testing and is integral to the 74LVTH16646MTDX's use in modular telecom and industrial chassis systems.

What is the purpose of bushold inputs in the 74LVTH16646MTDX?

Bushold inputs in the 74LVTH16646MTDX actively retain the last valid logic state on any floating A or B data line without external pull-up resistors. This eliminates 32 discrete components in typical 16-bit implementations, reduces PCB area, avoids weak pull-up current leakage, and enhances noise immunity - a key differentiator of the 74LVTH16646MTDX versus non-bushold variants like the 74LVT16646.

Can the 74LVTH16646MTDX interface directly with 5V logic devices?

Yes, the 74LVTH16646MTDX accepts input voltages up to 5.5 V and tolerates 5V signals on all A and B I/O pins while operating from a 3.3V supply. Its outputs swing rail-to-rail within the 3.3V domain but meet TTL input thresholds for 5V devices, enabling direct connection to legacy microcontrollers, ASICs, and peripherals without level translators - a confirmed specification in the 74LVTH16646MTDX datasheet.

How many independent control groups does the 74LVTH16646MTDX have?

The 74LVTH16646MTDX has two independent 8-bit control groups: Group 1 (A0–A7/B0–B7) and Group 2 (A8–A15/B8–B15), each with dedicated DIR, OE, CPAB/CPBA, and SAB/SBA pins. This allows asymmetric operation - for example, Group 1 in stored mode while Group 2 runs transparently - providing flexible bus multiplexing not possible with single-control transceivers, and is explicitly defined in the 74LVTH16646MTDX functional description.

74LVTH16646MTDX Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: 74LVTH

Package/Case:: 56-TFSOP (0.240", 6.10mm Width)

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Logic Type:: Transceiver, Non-Inverting

Number of Elements:: 2

Number of Bits per Element:: 8

Input Type:: -

Output Type:: 3-State

Current - Output High, Low:: 32mA, 64mA

Voltage - Supply:: 2.7V ~ 3.6V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 56-TSSOP

74LVTH16646MTDX FAQ

1.How can I place an order for 74LVTH16646MTDX through Aetrix?

Please submit a Request for Quotation (RFQ) for 74LVTH16646MTDX on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for 74LVTH16646MTDX reliable?

The price and inventory of 74LVTH16646MTDX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LVTH16646MTDX is usually 5 days.

3.What payment methods are accepted for 74LVTH16646MTDX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LVTH16646MTDX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74LVTH16646MTDX?

74LVTH16646MTDX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74LVTH16646MTDX order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for 74LVTH16646MTDX?

For technical support, including 74LVTH16646MTDX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LVTH16646MTDX requirements.

6.How does Aetrix verify that 74LVTH16646MTDX is sourced from the original manufacturer or authorized distributors?

All 74LVTH16646MTDX products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that 74LVTH16646MTDX meets industry standards.

7.What is the process for return or replacement of 74LVTH16646MTDX?

All 74LVTH16646MTDX units undergo pre-shipment inspection (PSI). If there is an issue with 74LVTH16646MTDX, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The 74LVTH16646MTDX part is unused and in its original packaging.

Return procedure for 74LVTH16646MTDX:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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