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NXP Semiconductors 74LVT646D,118
- Part No.:
- 74LVT646D,118
- Manufacturer:
- NXP Semiconductors
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74LVT646D,118.pdf
- Description:
- IC TXRX NON-INVERT 3.6V 24SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,955
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Product details
Overview
74LVT646D,118 from NXP Semiconductors (formerly Philips) is a 3.3V octal bus transceiver/register with 3-State outputs, combining bidirectional data transfer and dual independent D-type register functionality in a single 24-pin SO package. It supports real-time and stored-data multiplexing between A and B buses, delivers ±64mA/–32mA output drive, and interfaces directly with 5V TTL systems. Used in high-speed backplane and memory interface applications requiring bus isolation and data staging.
For engineers reviewing the 74LVT646D,118 datasheet, 74LVT646D,118 pinout, 74LVT646D,118 application, or 74LVT646D,118 equivalent, key selection criteria include its dual-register architecture, bus-hold inputs eliminating external pull-ups, power-up 3-State behavior, and compatibility with mixed-voltage (3.3V core / 5V I/O) system designs.
Technical Context
The 74LVT646D,118 integrates transceiver logic and edge-triggered D-flip-flops for both A and B buses, enabling simultaneous storage and real-time transfer via independent CPAB/CPBA clocks and SAB/SBA select controls. Its DIR pin determines data flow direction during OE-active operation, while OE=High enables isolation mode for selective register loading without bus contention.
It features BiCMOS process technology optimized for 3.3V VCC operation, with TTL-compatible input thresholds (VIL = 0.8V, VIH = 2.0V), 5V-tolerant I/Os, and bus-hold circuitry on all data pins (±75µA overdrive current). Propagation delays are as low as 1.3ns (An→Bn at 3.3V), supporting up to 150MHz clock frequency under industrial temperature conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply | 2.7V to 3.6V - Enables stable operation in modern 3.3V logic domains while maintaining backward compatibility with 5V signal environments. |
| Output Drive | +64mA / –32mA - Supports direct driving of heavy capacitive loads or multiple TTL inputs without external buffers. |
| tPLH/tPHL | 1.3ns to 2.8ns (An↔Bn) - Ensures sub-3ns latency for high-throughput data routing in memory and peripheral interfaces. |
| Bus-Hold Current | ±75µA - Eliminates need for external pull-up resistors on unused data lines, reducing BOM count and PCB space. |
| fMAX | 150MHz at VCC = 3.3V - Validates suitability for fast synchronous bus architectures including local bus and ISA extensions. |
| ICCZ Quiescent Current | 0.13mA (outputs disabled) - Minimizes standby power in power-sensitive embedded control modules. |
| Input Voltage Range | 0V to 5.5V - Allows safe interfacing with legacy 5V logic without level-shifting circuitry. |
Pinout & Package
74LVT646D,118 is housed in a 24-pin plastic small outline (SO) package per SOT163-1, 7.5mm body width, surface-mount compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 23 | CPAB / CPBA | A-to-B and B-to-A clock inputs - Edge-triggered clocks independently load data into respective registers on rising edge. |
| 2, 22 | SAB / SBA | Select inputs controlling real-time vs. registered data path - Determines whether transceiver passes live or latched bus data. |
| 3 | DIR | Direction control - Sets B bus as sink (DIR=High) or A bus as sink (DIR=Low) when OE is active. |
| 4–11 | A0–A7 | Bidirectional A-side I/O with bus-hold - Functions as input or output depending on DIR/OE state; retains last valid logic state when floating. |
| 13–20 | B0–B7 | Bidirectional B-side I/O with bus-hold - Mirrors A-side functionality with independent register storage capability. |
| 21 | OE | Active-low output enable - Disables all outputs to high-impedance state while preserving internal register contents and input functionality. |
| 12 | GND | Ground reference - Common return path for all internal logic and I/O circuits. |
| 24 | VCC | 3.3V supply input - Powers internal BiCMOS logic; must be decoupled locally per high-speed design practice. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent register banks | Enables concurrent capture of A and B bus data without cross-contamination, critical for handshake-free interprocessor communication. |
| Multiplexed real-time/stored data paths | Allows dynamic switching between live bus monitoring and previously captured snapshots using SAB/SBA pins - essential for diagnostic and debug modes. |
| Power-up 3-State and reset | Prevents bus contention during power ramp-up by holding outputs in high-Z until VCC stabilizes, simplifying system power sequencing. |
| Live insertion/extraction support | Permits hot-swap capability in modular backplanes without damaging connected devices or disrupting adjacent bus segments. |
| Latch-up immunity >500mA | Meets JEDEC Std 17 - ensures robustness against transient voltage spikes and ESD events in industrial and telecom infrastructure. |
Applications
| Memory Interface Buffering | Backplane Data Multiplexing |
|---|---|
|
Use Scenario: Isolating and synchronizing data between a 32-bit microprocessor bus and asynchronous SRAM modules operating at different timing margins. IC Role / Device Role / Timing Role: Acts as a registered transceiver that stages address/data writes before committing to memory, decoupling processor timing from memory access latency. Use Value: Eliminates wait-state insertion by absorbing timing skew between CPU and memory subsystems, improving effective bandwidth by up to 22% in burst-mode transfers. |
Use Scenario: Managing shared data lanes across multiple plug-in cards in a modular test instrumentation chassis. IC Role / Device Role / Timing Role: Provides bidirectional, direction-controlled data routing with register hold capability to prevent bus collisions during card insertion/removal. Use Value: Enables deterministic data capture from any active slot without arbitration overhead, supporting real-time waveform acquisition at 100+ MS/s aggregate rate. |
| Legacy System Voltage Translation | Industrial PLC I/O Expansion |
|
Use Scenario: Interfacing a modern 3.3V FPGA controller with legacy 5V peripheral ICs (e.g., UARTs, ADCs) on the same PCB. IC Role / Device Role / Timing Role: Serves as a level-translating bus buffer with built-in latching, allowing the FPGA to sample stable 5V signals without external level shifters. Use Value: Reduces component count by 4–6 discrete level-shifters per bus segment while maintaining full 5V noise margin and 150MHz throughput. |
Use Scenario: Expanding digital I/O capacity in programmable logic controllers where field modules operate at varying supply voltages and timing requirements. IC Role / Device Role / Timing Role: Functions as a configurable I/O register bank with bus-hold protection, storing sensor actuator states during scan cycle transitions. Use Value: Prevents spurious I/O toggling during PLC program execution gaps, ensuring deterministic safety-critical output behavior per IEC 61508 SIL-2 requirements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal registered transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC646A | Lower drive (+24mA/–24mA), 1.65–3.6V VCC range, no bus-hold inputs | Requires external pull-ups on unused pins; suited for ultra-low-power portable designs but lacks 5V tolerance | Choose when power budget <10mW per device and 5V interface is unnecessary |
| 74ALVT646 | Higher speed (tPLH = 1.1ns), 2.3–3.6V VCC, identical pinout and bus-hold | Compatible drop-in replacement with tighter timing margins for >200MHz clock domains | Choose when upgrading existing 74LVT646D,118 designs for higher throughput without layout change |
Compared with SN74LVC646A and 74ALVT646, the 74LVT646D,118 uniquely balances 5V-tolerant I/O, integrated bus-hold, and industrial-grade latch-up immunity - making it optimal for mixed-voltage industrial backplanes where reliability outweighs marginal speed gains.
Availability
74LVT646D,118 is available at Aetrix Electronics and suitable for memory interface buffering, backplane data multiplexing, legacy system voltage translation, and industrial PLC I/O expansion requiring stable component supply across extended product lifecycles.
Supply support for 74LVT646D,118 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
NXP Semiconductors, formerly Philips Semiconductors, is a global leader in high-performance analog and logic ICs, with expertise in automotive, industrial, and communications semiconductors.
The 74LVT646D,118 belongs to the LVT (Low-Voltage TTL) logic family, engineered for seamless integration between emerging 3.3V systems and legacy 5V infrastructure in industrial control and telecom equipment.
FAQ
What is the maximum clock frequency supported by the 74LVT646D,118?
The 74LVT646D,118 supports a maximum clock frequency of 150MHz at VCC = 3.3V ± 0.3V across the full industrial temperature range (–40°C to +85°C), as specified in the AC Characteristics table. This rating applies to CPAB and CPBA inputs driving register updates and is validated under standard load conditions (CL = 50pF, RL = 500Ω).
Does the 74LVT646D,118 require external pull-up resistors on unused data pins?
No, the 74LVT646D,118 includes integrated bus-hold circuitry on all A0–A7 and B0–B7 pins, providing ±75µA overdrive current to maintain the last valid logic state. This eliminates the need for external pull-up resistors, reducing bill-of-materials cost and PCB area while improving noise immunity on unterminated stubs.
Can the 74LVT646D,118 interface directly with 5V logic systems?
Yes, the 74LVT646D,118 features 5V-tolerant inputs and outputs, with absolute maximum input voltage rated to +7.0V and operational input voltage range up to +5.5V. Its TTL-compatible thresholds (VIH = 2.0V, VIL = 0.8V) allow direct connection to 5V CMOS and TTL devices without level-shifting circuitry.
What happens to the outputs of the 74LVT646D,118 during power-up?
During power-up, the 74LVT646D,118 asserts power-up 3-State behavior: all outputs remain in high-impedance until VCC reaches a stable level, preventing bus contention. Additionally, it incorporates power-up reset logic that initializes internal registers to a known state, ensuring deterministic startup in mission-critical systems.
Is the 74LVT646D,118 pin-compatible with other packages in the same family?
Yes, the 74LVT646D,118 (SO package, SOT163-1) shares identical pinout and electrical characteristics with the 74LVT646DB (SSOP) and 74LVT646PW (TSSOP) variants. All three packages use the same 24-pin configuration, function mapping, and timing specifications, enabling drop-in replacement based on board space and thermal requirements.
74LVT646D,118 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- NXP Semiconductors
- Series:
- 74LVT
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- 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:
- 24-SO
74LVT646D,118 FAQ
1.How can I place an order for 74LVT646D,118 through Aetrix?
Please submit a Request for Quotation (RFQ) for 74LVT646D,118 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 74LVT646D,118 reliable?
The price and inventory of 74LVT646D,118 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LVT646D,118 is usually 5 days.
3.What payment methods are accepted for 74LVT646D,118?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LVT646D,118 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74LVT646D,118?
74LVT646D,118 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74LVT646D,118 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 74LVT646D,118?
For technical support, including 74LVT646D,118 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LVT646D,118 requirements.
6.How does Aetrix verify that 74LVT646D,118 is sourced from the original manufacturer or authorized distributors?
All 74LVT646D,118 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 74LVT646D,118 meets industry standards.
7.What is the process for return or replacement of 74LVT646D,118?
All 74LVT646D,118 units undergo pre-shipment inspection (PSI). If there is an issue with 74LVT646D,118, 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 74LVT646D,118 part is unused and in its original packaging.
Return procedure for 74LVT646D,118:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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