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

onsemi 74VHC161284MTDX

Name: 74VHC161284MTDX
Brand: onsemi
SKU: 74VHC161284MTDX
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74VHC161284MTDX

Manufacturer:: onsemi

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: -

Datasheet:: 74VHC161284MTDX.pdf

Description:: LINE TRANSCEIVER, 13 FUNC, 14 DR

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Product details

Overview

The 74VHC161284MTDX from Fairchild Semiconductor is a IEEE 1284-compliant bidirectional parallel transceiver IC designed for ECP-mode printer and peripheral interfaces. It integrates eight bidirectional data buffers (A1–A8/B1–B8), eleven control/status buffers, and supports both Level 1 and Level 2 signaling. Cable-side outputs deliver ±14 mA drive capability with optimized 35–55 Ω output impedance and internal pull-ups, enabling robust 5.5 V-tolerant cable driving in PC-parallel port applications.

For engineers reviewing the 74VHC161284MTDX datasheet, pinout, applications, or equivalent options, key selection considerations include its dual-voltage I/O tolerance (5.5 V on cable side, 7.0 V max), open-drain/high-drive configurability via HD input, flow-through pin layout for simplified PCB routing, and built-in hysteresis on all inputs except HLH for noise immunity in noisy industrial or office environments.

Technical Context

The 74VHC161284MTDX implements full IEEE 1284 physical layer signaling using two independent data paths: A1–A8 ↔ B1–B8 for bidirectional data transfer and A9–A13 → Y9–Y13 + C14–C17 → A14–A17 for control/status handshaking. Direction is controlled by DIR, while HD selects between high-drive (14 mA) and open-drain modes on cable-side outputs (B1–B8, Y9–Y13).

All cable-side inputs/outputs (except HLHIN) feature internal pull-up resistors (1150–1650 Ω), and the device guarantees ≤30 ns propagation delay across all signal paths (A→B, B→A, A→Y, C→A) at 4.5–5.5 V supply. Power-down leakage is limited to 250 µA total ICC when disabled.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage	4.5 V to 5.5 V - Ensures compatibility with standard 5 V logic systems and stable operation under typical PC bus voltage tolerances.
Cable-Side Output Drive	±14 mA - Enables direct termination of parallel cables without external drivers, meeting IEEE 1284 slew and drive requirements.
Output Impedance	35 Ω to 55 Ω - Matches characteristic impedance of parallel cables to minimize reflections and signal integrity degradation.
Propagation Delay	≤30 ns - Guarantees timing compliance for ECP mode handshaking and high-speed bidirectional data bursts up to ~3 MB/s.
Input Hysteresis	0.4 V (A/B/C pins), 0.8 V (C14–C17) - Provides noise margin against crosstalk and ground bounce in shared-connector environments.
Operating Temperature	−40 °C to +85 °C - Supports deployment in industrial PCs, embedded controllers, and thermal-challenged peripheral enclosures.
I/O Voltage Tolerance	B1–B8/Y9–Y13: 0–5.5 V DC - Allows safe interfacing with legacy 5 V peripherals even during hot-plug or power sequencing mismatches.

Pinout & Package

74VHC161284MTDX is packaged in a 48-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 6.1 mm wide, with 0.5 mm lead pitch and exposed pad not present. The flow-through pin arrangement minimizes trace crossing and simplifies routing between host (cable side) and peripheral (A-side) connectors.

Pin/Terminal	Circuit Role	Design Meaning
A1–A8	Peripheral-side bidirectional I/O	Connects to peripheral controller data bus; direction controlled by DIR; CMOS low-drive outputs.
B1–B8	Cable-side bidirectional I/O	Open-drain or high-drive outputs (HD-controlled); internal pull-ups; drives parallel cable directly.
A9–A13	Peripheral-side inputs	Accept handshake signals (e.g., nAck, Busy, Select) from host; hysteresis improves noise immunity.
Y9–Y13	Cable-side outputs	Drive host-side status lines (e.g., nAck, Busy); open-drain with internal pull-up; 5.5 V tolerant.
C14–C17	Cable-side inputs	Receive host control signals (e.g., Strobe, AutoFd, Init); internal pull-ups ensure defined state when unconnected.
A14–A17	Peripheral-side outputs	Transmit peripheral control responses (e.g., nAck, Busy) back to host; standard CMOS outputs.
DIR	Direction control input	Active-HIGH selects A→B/Y data flow; LOW enables B→A/A→Y flow - essential for ECP forward/reverse channel switching.
HD	High-drive enable input	Active-HIGH configures B1–B8/Y9–Y13 as 14 mA push-pull; LOW enables open-drain mode for wired-OR bus sharing.
PLH / PLHIN	Peripheral Logic HIGH I/O	Open-drain bidirectional signal for ECP channel negotiation; internal pull-up ensures default HIGH state.
HLH / HLHIN	Host Logic HIGH I/O	Open-drain bidirectional signal; no internal pull-up - requires external termination per IEEE 1284 spec.

Key Features

Feature	Design Value
IEEE 1284 Level 1 & 2 compliance	Fully implements physical layer signaling, timing, and electrical requirements for both compatibility and ECP performance modes.
Flow-through pin configuration	Eliminates need for PCB layer swaps or vias between host connector and peripheral ASIC - reduces layout complexity and signal skew.
Configurable cable-side drive mode	HD input selects between 14 mA high-drive (for point-to-point) or open-drain (for multi-drop/bus-sharing) operation.
Integrated termination resistors	Internal 1150–1650 Ω pull-ups on B/Y/C pins reduce BOM count and improve consistency vs. discrete resistor networks.
Power-down leakage control	Guaranteed ≤250 µA total ICC in disable state - critical for low-power suspend/resume behavior in portable or energy-sensitive systems.

Applications

Laser Printer Interface	Industrial PLC Parallel Port
Use Scenario: Connecting an FPGA-based print controller to a legacy laser printer via IEEE 1284-compliant parallel cable. IC Role / Device Role / Timing Role: Physical-layer transceiver managing bidirectional data bursts and real-time handshaking (Strobe, Busy, nAck) in ECP mode. Use Value: Eliminates need for discrete level shifters and termination resistors; 30 ns propagation delay ensures reliable 2.5 MB/s ECP throughput.	Use Scenario: Adding parallel port connectivity to a DIN-rail mounted PLC for legacy machine tool communication. IC Role / Device Role / Timing Role: Robust interface IC isolating industrial noise from sensitive controller logic while driving long parallel cables. Use Value: Input hysteresis and internal pull-ups prevent false triggers in electrically noisy factory environments; −40 °C to +85 °C rating ensures field reliability.
Embedded PC Expansion Card	POS Terminal Peripheral Hub
Use Scenario: Integrating IEEE 1284 support into a compact x86 SBC expansion card for kiosk or medical device use. IC Role / Device Role / Timing Role: Bidirectional transceiver bridging SoC GPIO bank to external parallel port header with minimal footprint. Use Value: TSSOP-48 package fits dense layouts; 5.5 V-tolerant I/O allows safe connection to legacy peripherals without level-shifting circuitry.	Use Scenario: Enabling simultaneous connection of receipt printer, barcode scanner, and cash drawer to a single POS terminal parallel port. IC Role / Device Role / Timing Role: Multi-peripheral interface hub using open-drain mode (HD = LOW) for wired-OR control line sharing. Use Value: Configurable HD input enables bus arbitration without external logic; internal pull-ups maintain valid logic states during hot-plug events.

Laser Printer Interface

Industrial PLC Parallel Port

Use Scenario: Connecting an FPGA-based print controller to a legacy laser printer via IEEE 1284-compliant parallel cable.

IC Role / Device Role / Timing Role: Physical-layer transceiver managing bidirectional data bursts and real-time handshaking (Strobe, Busy, nAck) in ECP mode.

Use Value: Eliminates need for discrete level shifters and termination resistors; 30 ns propagation delay ensures reliable 2.5 MB/s ECP throughput.

Use Scenario: Adding parallel port connectivity to a DIN-rail mounted PLC for legacy machine tool communication.

IC Role / Device Role / Timing Role: Robust interface IC isolating industrial noise from sensitive controller logic while driving long parallel cables.

Use Value: Input hysteresis and internal pull-ups prevent false triggers in electrically noisy factory environments; −40 °C to +85 °C rating ensures field reliability.

Embedded PC Expansion Card

POS Terminal Peripheral Hub

Use Scenario: Integrating IEEE 1284 support into a compact x86 SBC expansion card for kiosk or medical device use.

IC Role / Device Role / Timing Role: Bidirectional transceiver bridging SoC GPIO bank to external parallel port header with minimal footprint.

Use Value: TSSOP-48 package fits dense layouts; 5.5 V-tolerant I/O allows safe connection to legacy peripherals without level-shifting circuitry.

Use Scenario: Enabling simultaneous connection of receipt printer, barcode scanner, and cash drawer to a single POS terminal parallel port.

IC Role / Device Role / Timing Role: Multi-peripheral interface hub using open-drain mode (HD = LOW) for wired-OR control line sharing.

Use Value: Configurable HD input enables bus arbitration without external logic; internal pull-ups maintain valid logic states during hot-plug events.

Equivalent & Alternatives

The following parts are listed as comparable options for similar IEEE 1284 transceiver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
74ACT1284MTCX	Single-channel, non-ECP-optimized; lacks HD control and flow-through pinout; lower drive (8 mA) and higher propagation delay (35 ns).	Supports only basic IEEE 1284 Level 1; unsuitable for ECP burst transfers or high-noise environments due to missing hysteresis.	Select only for cost-sensitive, low-speed legacy printer interfaces where ECP features are unused.
SN74LVCH161284DGGR	16-bit version with 3.3 V core logic; 5 V-tolerant I/O; supports hot-swap but lacks internal pull-ups on C14–C17 and Y9–Y13.	Requires external 10 kΩ pull-ups for IEEE 1284 compliance; better suited for modern 3.3 V systems than legacy 5 V designs.	Prefer for new 3.3 V designs with space for discrete termination; avoid if minimizing BOM count is critical.

Compared with 74ACT1284MTCX and SN74LVCH161284DGGR, the 74VHC161284MTDX uniquely combines ECP-ready timing, integrated pull-ups, flow-through routing, and 5 V system compatibility - making it the optimal choice for drop-in upgrades of legacy parallel port hardware without layout revision.

Availability

74VHC161284MTDX is available at Aetrix Electronics and suitable for laser printer interfaces, industrial PLC parallel ports, embedded PC expansion cards, and POS terminal peripheral hubs requiring stable component supply and long-term obsolescence management.

Supply support for 74VHC161284MTDX 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

Fairchild Semiconductor was a U.S.-based analog and power IC manufacturer acquired by ON Semiconductor in 2016; known for high-reliability logic, interface, and power management solutions.

The 74VHC161284MTDX belongs to Fairchild's VHC (Very High Speed CMOS) logic family, engineered specifically for noise-immune, high-drive parallel interface applications in PC peripheral and industrial control systems.

FAQ

What is the primary function of the 74VHC161284MTDX in a parallel port design?

The 74VHC161284MTDX serves as a full IEEE 1284-compliant bidirectional transceiver that bridges host (cable side) and peripheral (A-side) logic domains. It manages data flow (A1–A8 ↔ B1–B8), control/status handshaking (A9–A13 → Y9–Y13, C14–C17 → A14–A17), and ECP-specific signals (PLH/HLH). Its DIR and HD inputs configure direction and drive strength, enabling robust implementation of both Level 1 and Level 2 protocols without external components. The 74VHC161284MTDX is essential for achieving timing-compliant, noise-resistant parallel communication in legacy and industrial systems.

Does the 74VHC161284MTDX support hot-plug detection or automatic protocol negotiation?

No, the 74VHC161284MTDX does not perform protocol negotiation or hot-plug detection. It is a physical-layer transceiver only - implementing signal buffering, drive strength control, and termination per IEEE 1284 electrical specifications. Protocol-level functions such as ECP mode entry, channel reversal, or data compression are handled by the host and peripheral controllers. The 74VHC161284MTDX provides the necessary I/O structure (e.g., PLH/HLH pins, DIR/HD control) to support those higher-layer operations, but does not autonomously detect or initiate them. System firmware must manage timing and state transitions.

Can the 74VHC161284MTDX operate with a 3.3 V supply voltage?

No, the 74VHC161284MTDX is not specified for 3.3 V operation. Its recommended operating supply range is strictly 4.5 V to 5.5 V, and absolute maximum ratings cap VCC at 7.0 V. While some VHC-family devices tolerate lower voltages, the 74VHC161284MTDX's DC and AC characteristics - including VOL, VOH, propagation delay, and output drive - are only guaranteed within the 4.5–5.5 V window. Using 3.3 V risks undefined logic thresholds, excessive propagation delay (>30 ns), and failure to meet IEEE 1284 slew rate requirements. For 3.3 V systems, consider the SN74LVCH161284DGGR instead.

How does the HD input affect the electrical behavior of B1–B8 and Y9–Y13 outputs?

When HD = HIGH, B1–B8 and Y9–Y13 operate as high-drive CMOS outputs capable of sourcing/sinking ±14 mA, with output impedance tightly controlled between 35 Ω and 55 Ω for optimal cable driving. When HD = LOW, those same pins switch to open-drain mode, disabling the pull-down transistor and leaving only the internal 1150–1650 Ω pull-up active - enabling wired-OR bus sharing and compatibility with legacy peripherals requiring open-collector signaling. This dual-mode capability allows the 74VHC161284MTDX to serve both point-to-point and multi-drop parallel configurations without external hardware changes.

Is the 74VHC161284MTDX pin-compatible with the 74VHC161284MEA variant?

Yes, the 74VHC161284MTDX and 74VHC161284MEA share identical pinouts and electrical specifications - differing only in package type: MTDX uses TSSOP-48 (JEDEC MO-153, 6.1 mm wide), while MEA uses SSOP-48 (JEDEC MO-118, 0.300" wide). Both have the same 48-pin flow-through arrangement, identical pin naming (A1–A17, B1–B8, Y9–Y13, etc.), and match in all functional, timing, and DC parameters. PCB layout must account for mechanical differences (footprint, solder mask, thermal pad), but no signal routing or schematic changes are needed when substituting one for the other.

74VHC161284MTDX Specifications

Product attributes: Attribute value

Manufacturer:: onsemi

Series:: *

Package/Case:: -

Packaging:: Bulk

Product Status:: Active

Logic Type:: -

Number of Elements:: -

Number of Bits per Element:: -

Input Type:: -

Output Type:: -

Current - Output High, Low:: -

Voltage - Supply:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

74VHC161284MTDX FAQ

1.How can I place an order for 74VHC161284MTDX through Aetrix?

Please submit a Request for Quotation (RFQ) for 74VHC161284MTDX 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 74VHC161284MTDX reliable?

The price and inventory of 74VHC161284MTDX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74VHC161284MTDX is usually 5 days.

3.What payment methods are accepted for 74VHC161284MTDX?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74VHC161284MTDX transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74VHC161284MTDX?

74VHC161284MTDX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74VHC161284MTDX 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 74VHC161284MTDX?

For technical support, including 74VHC161284MTDX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74VHC161284MTDX requirements.

6.How does Aetrix verify that 74VHC161284MTDX is sourced from the original manufacturer or authorized distributors?

All 74VHC161284MTDX 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 74VHC161284MTDX meets industry standards.

7.What is the process for return or replacement of 74VHC161284MTDX?

All 74VHC161284MTDX units undergo pre-shipment inspection (PSI). If there is an issue with 74VHC161284MTDX, 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 74VHC161284MTDX part is unused and in its original packaging.

Return procedure for 74VHC161284MTDX:

1.Submit a request within 90 days.

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

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