My Inquiry
My Account
Texas Instruments SN74LVC16646DL
- Part No.:
- SN74LVC16646DL
- Manufacturer:
- Texas Instruments
- Package:
- 56-BSSOP (0.295", 7.50mm Width)
- Datasheet:
-
SN74LVC16646DL.pdf
- Description:
- 16-BIT BUS XCEIVER AND REGISTER
- Quantity:
- Payment:
- Shipping:
Inventory:2,582
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74LVC16646DL from Texas Instruments is a 16-bit bus transceiver and register with 3-state outputs, designed for 3.3-V operation. It functions as two independent 8-bit transceivers or one unified 16-bit unit, integrates D-type flip-flops for data latching, supports real-time and stored-data multiplexing via SAB/SBA controls, and features bus-hold on all A/B data inputs to eliminate external pull resistors - used in high-density memory interface and backplane data routing applications.
For engineers reviewing the SN74LVC16646DL datasheet, SN74LVC16646DL pinout, SN74LVC16646DL application, or SN74LVC16646DL equivalent, key selection considerations include its dual-clock (CLKAB/CLKBA) register control, DIR/OE-driven bidirectional flow, bus-hold input stabilization, 3.3-V ±10% supply tolerance, and DL-package thermal performance (1.4 W at 55°C).
Technical Context
The SN74LVC16646DL implements dual 8-bit register-controlled transceivers with independent clock inputs (CLKAB, CLKBA) and select controls (SAB, SBA) enabling glitch-free switching between real-time and registered data paths. Its EPIC™ submicron CMOS process delivers low ground bounce (VOLP < 0.8 V) and undershoot immunity (VOHV > 2 V) at 3.3 V.
Operation supports four fundamental bus-management modes: real-time A→B or B→A transfer, simultaneous storage from A/B buses, and selective output of stored data to either bus - all under OE/DIR coordination without requiring external decode logic.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2.7 V to 3.6 V - ensures compatibility with 3.3-V systems including LVTTL and mixed-voltage I/O domains. |
| Max Clock Frequency | 100 MHz at VCC = 3.3 V - enables high-speed synchronous data capture in memory buffers and FPGA interconnects. |
| Output Drive | ±24 mA at VCC = 3 V - sufficient to drive 50-pF loads across PCB traces without signal integrity degradation. |
| Propagation Delay | 1.5–8.5 ns (CLKAB/CLKBA to A/B) - supports tight timing budgets in DDR-adjacent control paths and address latching. |
| Bus-Hold Current | ±75 µA at VI = 2 V - actively maintains valid logic levels on floating A/B inputs, removing need for 10-kΩ external bias resistors. |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded controllers and telecom line cards. |
| Power Dissipation Cap. | 17 pF per transceiver (enabled), 4 pF (disabled) - reduces dynamic power in burst-mode data transfers. |
Pinout & Package
SN74LVC16646DL uses a 56-pin shrink small-outline (DL) package with 300-mil body width, optimized for high-pin-count board density and thermal dissipation (1.4 W max at TA = 55°C). Pin numbering follows standard top-view orientation with GND and VCC distributed across multiple pins for noise suppression.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1DIR, 2DIR | Direction Control Input | Determines data flow direction per 8-bit section: DIR = H enables A→B; DIR = L enables B→A when OE is low. |
| 1OE, 2OE | Output Enable Input | Active-low control: OE = L enables 3-state outputs; OE = H forces high-impedance, preserving bus isolation. |
| 1CLKAB, 2CLKAB 1CLKBA, 2CLKBA |
Register Clock Inputs | CLKAB↑ latches A-bus data into register; CLKBA↑ latches B-bus data - edge-triggered, asynchronous to DIR/OE. |
| 1SAB, 2SAB 1SBA, 2SBA |
Select Control Inputs | SAB = L selects real-time B→A transfer; SBA = L selects real-time A→B; SAB/SBA = H routes registered data. |
| A1–A8, B1–B8 (x2) | Bidirectional Data Terminals | 16 total I/O ports with bus-hold circuitry - accept and drive 3.3-V LVTTL signals; no external termination required. |
| VCC, GND (x8 each) | Power Distribution | Multiple VCC/GND pairs minimize IR drop and ground bounce across high-speed switching events. |
Key Features
| Feature | Design Value |
|---|---|
| Glitch-free multiplexing | Internal SAB/SBA decoding eliminates transient glitches during real-time ↔ registered data transitions - critical for error-free FIFO handshaking. |
| Integrated bus-hold | Active input hold circuitry maintains valid logic states on unused A/B lines - removes 16 external pull-up/down resistors and associated layout area. |
| Dual independent clocks | Separate CLKAB and CLKBA inputs allow asynchronous registration of A- and B-bus data - supports asymmetric timing in multi-master bus arbitration. |
| Low ground bounce | VOLP < 0.8 V at 3.3 V ensures stable reference for downstream receivers during simultaneous output switching - meets JEDEC JESD-8-6 noise limits. |
| Isolation mode support | When OE = H, A/B data can be independently stored in registers without bus contention - enables safe hot-swap initialization sequences. |
Applications
| Memory Interface Buffer | FPGA-to-ASIC Data Bridge |
|---|---|
|
Use Scenario: Bidirectional data path between SDRAM controller and memory module with timing-critical address/data strobes. IC Role / Device Role / Timing Role: Acts as registered transceiver synchronizing A/B bus transfers to CLKAB/CLKBA edges while buffering control signals with bus-hold stability. Use Value: Eliminates external latch ICs and pull resistors; 100-MHz clock support matches DDR SDRAM command rates; low VOLP prevents setup/hold violations in parallel bus layouts. |
Use Scenario: High-speed data exchange between Xilinx FPGA I/O banks and ASIC peripheral subsystem operating at different voltage thresholds. IC Role / Device Role / Timing Role: Provides level-shifted, registered 16-bit channel with independent clock domains (CLKAB for FPGA → ASIC, CLKBA for reverse path). Use Value: Enables glitch-free multiplexing of live vs. registered data; bus-hold prevents floating inputs during FPGA configuration; 3.3-V tolerance aligns with both device families. |
| Backplane Data Router | Industrial PLC I/O Module |
|
Use Scenario: Reconfigurable data routing across multi-slot VMEbus or CompactPCI backplanes with hot-swap capability. IC Role / Device Role / Timing Role: Functions as isolated bidirectional repeater with OE-controlled bus segmentation and DIR-selectable flow direction per slot. Use Value: Isolation mode (OE = H) allows safe insertion/removal; latch registers store status during reset; 85°C rating supports convection-cooled chassis environments. |
Use Scenario: Modular digital I/O expansion in programmable logic controllers where field wiring may float or induce noise. IC Role / Device Role / Timing Role: Buffers and registers sensor/actuator data between microcontroller and terminal blocks, with bus-hold preventing spurious interrupts from unterminated wires. Use Value: ±75 µA bus-hold current clamps inputs to valid logic levels without external components; –40°C to 85°C range ensures reliability in factory-floor temperature swings. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver and register applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVCH16646DL | Includes Schmitt-trigger inputs and higher noise margin (VIH = 2.0 V min); otherwise identical pinout, function, and timing. | Better suited for noisy industrial environments with slow-rising or degraded signal edges. | Choose SN74LVCH16646DL when interfacing to long cables or unfiltered sensors where input hysteresis improves robustness. |
| 74ALVC16646DL | Higher drive strength (±24 mA at 2.5 V), lower propagation delay (1.2 ns typ), but no bus-hold circuitry. | Requires external pull resistors on all A/B inputs; better for ultra-low-latency control loops where bus-hold is unnecessary. | Choose 74ALVC16646DL only if board space permits 16 external resistors and timing margins demand sub-8-ns tpd. |
Compared with SN74LVC16646DL, SN74LVCH16646DL adds input hysteresis for noise immunity without layout changes, while 74ALVC16646DL trades bus-hold for faster propagation - making SN74LVC16646DL the optimal balance of integration, robustness, and speed for general-purpose 3.3-V bus management.
Availability
SN74LVC16646DL is available at Aetrix Electronics and suitable for memory interface buffers, FPGA-to-ASIC bridges, and industrial PLC I/O modules requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for SN74LVC16646DL 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 delivering analog, embedded processing, and logic solutions with emphasis on reliability, scalability, and system-level integration.
The SN74LVC16646DL belongs to TI's Widebus™ family of advanced bus-interface devices, engineered specifically for high-speed, low-voltage data routing in memory subsystems and programmable logic interconnects.
FAQ
What is the recommended power-up sequence for SN74LVC16646DL to ensure high-impedance outputs?
To guarantee high-impedance outputs during power-up, OE must be held high until VCC stabilizes. TI recommends tying OE to VCC through a pullup resistor; minimum value depends on driver sink capability but typically ranges from 4.7 kΩ to 10 kΩ. This prevents bus contention before system initialization completes. The SN74LVC16646DL does not include internal power-on reset, so external sequencing remains essential for deterministic startup behavior of the SN74LVC16646DL.
Does SN74LVC16646DL support mixed-voltage operation between A and B buses?
No, the SN74LVC16646DL operates from a single VCC supply (2.7 V to 3.6 V) and does not support independent voltage domains on A and B buses. Both sides share the same logic threshold (VIH = 2.0 V min, VIL = 0.8 V max) referenced to that VCC. Interfacing to 2.5-V or 5-V systems requires external level-shifting circuitry - the SN74LVC16646DL itself is strictly a 3.3-V domain device.
How does bus-hold functionality work on SN74LVC16646DL, and what is its effective holding current?
Bus-hold circuitry on the SN74LVC16646DL uses weak feedback transistors to maintain the last-valid logic state on floating A/B inputs. At VI = 2 V and VCC = 3 V, it sources or sinks ±75 µA to stabilize the node - sufficient to override typical PCB leakage but not strong enough to drive transmission lines. This eliminates external pull resistors while ensuring deterministic startup and noise immunity. The SN74LVC16646DL's bus-hold is always active and cannot be disabled.
Can SN74LVC16646DL operate reliably at 2.5 V supply voltage?
No - the SN74LVC16646DL is not characterized or guaranteed for operation at 2.5 V. Its recommended VCC range is 2.7 V to 3.6 V, with electrical specifications (e.g., VOH ≥ 2.2 V, VOL ≤ 0.4 V, fmax = 80 MHz) validated only within that window. At 2.5 V, timing margins collapse, output drive degrades, and bus-hold may fail to engage. For 2.5-V systems, consider SN74LVC16245A or similar members of the LVC family explicitly rated down to 2.3 V.
What is the maximum capacitive load SN74LVC16646DL can drive while maintaining specified timing?
The SN74LVC16646DL's switching characteristics (tpd, ten, tdis) are specified with CL = 50 pF, representing total load including PCB trace capacitance, probe effects, and receiver input capacitance. Driving loads exceeding 50 pF increases propagation delay nonlinearly and may violate setup/hold windows - especially above 75 pF. For heavier loads, add series termination or reduce clock frequency; the SN74LVC16646DL's ±24-mA drive supports moderate fanout but not stub-based multidrop topologies.
SN74LVC16646DL Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVC
- Package/Case:
- 56-BSSOP (0.295", 7.50mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 2
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 1.65V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 56-SSOP
SN74LVC16646DL FAQ
1.How can I place an order for SN74LVC16646DL through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVC16646DL 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 SN74LVC16646DL reliable?
The price and inventory of SN74LVC16646DL are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVC16646DL is usually 5 days.
3.What payment methods are accepted for SN74LVC16646DL?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LVC16646DL transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LVC16646DL?
SN74LVC16646DL orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVC16646DL 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 SN74LVC16646DL?
For technical support, including SN74LVC16646DL datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVC16646DL requirements.
6.How does Aetrix verify that SN74LVC16646DL is sourced from the original manufacturer or authorized distributors?
All SN74LVC16646DL 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 SN74LVC16646DL meets industry standards.
7.What is the process for return or replacement of SN74LVC16646DL?
All SN74LVC16646DL units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVC16646DL, 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 SN74LVC16646DL part is unused and in its original packaging.
Return procedure for SN74LVC16646DL:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74LVC16646DL Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
