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Texas Instruments SN74BCT126AD
- Part No.:
- SN74BCT126AD
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74BCT126AD.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:15,284
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Product details
Overview
SN74BCT126AD from Texas Instruments is a quadruple bus buffer gate with 3-state outputs, designed for bidirectional data bus isolation and memory address register buffering in 5-V TTL-compatible systems. It features independent enable-controlled buffers, BiCMOS output drivers delivering ±64 mA sink/source capability, and operates from 0°C to 70°C with 4.5–5.5 V supply. Used in industrial control backplanes and legacy computing address latching.
For engineers reviewing the SN74BCT126AD datasheet, SN74BCT126AD pinout, SN74BCT126AD application, or SN74BCT126AD equivalent, key selection criteria include 3-state output timing (tPLH ≤ 6.3 ns), low ICCZ standby current (≤10 mA), high noise immunity (VIL = 0.8 V), and SOIC-14 RoHS-compliant packaging for through-hole or surface-mount compatibility.
Technical Context
The SN74BCT126AD implements four independent non-inverting buffers, each with dedicated active-high output-enable (OE) control. Its BiCMOS architecture combines bipolar input stages for TTL-level compatibility and CMOS output transistors for reduced power consumption and higher drive strength than standard TTL.
Each buffer supports hot-swap-capable 3-state operation: outputs enter high-impedance when OE is low, enabling shared bus arbitration without contention. Input clamp diodes and ESD protection (>2000 V per MIL-STD-883C) support robust operation in noisy industrial environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and mixed-voltage logic systems. |
| Operating Temperature | 0°C to 70°C - Qualified for commercial-grade embedded and industrial control applications. |
| Output Drive | 64 mA sink / 15 mA source - Sufficient to drive 50-pF loads across PCB traces and multiple TTL inputs. |
| Propagation Delay | tPLH ≤ 6.3 ns (A→Y) - Enables reliable operation in sub-100-MHz address/data bus timing budgets. |
| 3-State Enable Time | tPZL ≤ 10.7 ns (OE→Y) - Supports fast bus turnaround in multiplexed memory or peripheral interfaces. |
| Input Thresholds | VIL = 0.8 V, VIH = 2.0 V - Matches standard TTL logic levels for seamless integration with legacy 74-series devices. |
| ESD Rating | >2000 V HBM - Provides built-in protection against handling-induced electrostatic discharge during assembly. |
Pinout & Package
SN74BCT126AD is housed in a 14-pin plastic small-outline integrated circuit (SOIC) package (Package Drawing D), 3.90 mm wide, with 1.27 mm pitch and RoHS-compliant Cu/Ni/Pd/Au terminal finish. Moisture Sensitivity Level is Level-1 (unlimited floor life at ≤30°C/60% RH).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | OE (Output Enable) | Active-high control per buffer; drives corresponding Y output to high-Z when low. |
| 2, 5, 9, 12 | A (Input) | Non-inverting data input for each of four independent buffers. |
| 3, 6, 8, 11 | Y (Output) | 3-state buffered output; follows A when OE is high, high-Z when OE is low. |
| 7 | GND | Ground reference for all logic and output stages; must be low-impedance connection. |
| 14 | VCC | Positive supply rail (4.5–5.5 V); requires local 0.1-µF ceramic decoupling capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| BiCMOS Output Stage | Combines TTL-compatible input thresholds with CMOS-like low ICCZ (≤10 mA) and high drive strength (64 mA sink). |
| Independent 3-State Control | Four separate OE pins allow selective bus segment isolation without affecting other channels. |
| TTL-Level Input Compatibility | Accepts standard 0.8 V/2.0 V input thresholds-no level-shifting required when interfacing with 74LS/74F families. |
| High-Noise Immunity | Input clamp current rating (–18 mA) and ESD protection (>2000 V) ensure reliability in electrically harsh environments. |
| SOIC-14 RoHS Packaging | Green (RoHS & no Sb/Br) construction with CU NIPDAU terminations meets modern environmental compliance requirements. |
Applications
| Industrial Backplane Bus Isolation | Legacy Memory Address Latching |
|---|---|
Use Scenario: Isolating modular I/O cards on a 5-V industrial backplane to prevent signal contention during hot-swap or card replacement. IC Role / Device Role / Timing Role: SN74BCT126AD acts as a directionally agnostic bus buffer, enabling controlled data flow between master controller and peripheral modules via independent OE gating. Use Value: Prevents bus conflicts during dynamic reconfiguration while maintaining sub-7-ns propagation delay for deterministic timing in real-time control loops. | Use Scenario: Latching 16-bit address lines from a microprocessor to static RAM or EPROM in retro-computing or instrumentation systems. IC Role / Device Role / Timing Role: SN74BCT126AD serves as an address register buffer, driving high-capacitance memory address buses with TTL-compatible voltage levels and fast enable/disable transitions. Use Value: Delivers 64 mA sink current to overcome trace capacitance and fan-out loading, ensuring setup/hold time margins are preserved across temperature and voltage extremes. |
| Microcontroller Peripheral Interface | Test Equipment Signal Conditioning |
Use Scenario: Interfacing a 5-V microcontroller GPIO port to external peripherals requiring higher drive strength or bus arbitration. IC Role / Device Role / Timing Role: SN74BCT126AD functions as a programmable output driver, where firmware controls individual OE pins to manage peripheral enable sequencing and reduce MCU I/O loading. Use Value: Eliminates need for discrete transistor arrays or additional level shifters-reduces BOM count and PCB area while preserving timing predictability. | Use Scenario: Conditioning digital stimulus signals in automated test equipment (ATE) before routing to device-under-test (DUT) pins. IC Role / Device Role / Timing Role: SN74BCT126AD provides clean, slew-controlled buffering with precise 3-state control to isolate DUT inputs during measurement phases. Use Value: High noise margin and fast tPZL/tPHZ (≤10.7 ns) enable accurate signal edge placement and minimize crosstalk-induced timing jitter in high-speed test patterns. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT126N | AC-family CMOS; lower ICCZ (≤2 µA), higher VOH (≥4.4 V), but only 24 mA IOL. | Better for ultra-low-power 5-V systems; insufficient drive for heavy TTL loads or long traces. | Select when power efficiency > drive strength; verify load capacitance and fan-out compatibility. |
| 74LS126N | Standard TTL; higher ICC (32 mA typical), slower tPLH (15 ns), no BiCMOS benefits. | Suitable for cost-sensitive legacy designs where speed and power are secondary. | Choose only for drop-in replacement in existing LS-based boards; expect higher thermal load and timing margin reduction. |
Compared with SN74ACT126N and 74LS126N, the SN74BCT126AD uniquely balances TTL compatibility, 64-mA drive, and sub-10-ns timing-making it optimal for upgrading aging 74LS systems without redesigning layout or recalculating timing budgets.
Availability
SN74BCT126AD is available at Aetrix Electronics and suitable for industrial backplane bus isolation, legacy memory address latching, and microcontroller peripheral interface applications requiring stable component supply and long-term obsolescence management.
Supply support for SN74BCT126AD 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74BCT126AD belongs to TI's legacy BCT logic family, engineered specifically for high-drive, 3-state bus interfacing in 5-V systems where TTL compatibility and robustness outweigh ultra-low-power requirements.
FAQ
What is the maximum output sink current specification for SN74BCT126AD?
The SN74BCT126AD supports a maximum low-level output current (IOL) of 64 mA per channel under recommended operating conditions (VCC = 4.5 V, TA = 0°C to 70°C). This value is confirmed in the "Recommended Operating Conditions" table of the SCBS252A datasheet and enables direct driving of multiple TTL inputs or moderate PCB trace capacitance without external amplification. Exceeding this limit risks parametric shift or accelerated wear.
Does SN74BCT126AD support hot-swap operation on shared data buses?
Yes, SN74BCT126AD supports hot-swap operation due to its true 3-state outputs and input clamp diodes rated for –18 mA. When OE is low, outputs enter high-impedance state with leakage ≤ ±50 µA, preventing bus contention during live insertion/removal. The device's ESD rating (>2000 V HBM) and robust absolute maximum ratings (e.g., VO up to 5.5 V in disabled state) further enhance system resilience during hot-swap events.
What is the pin-compatible replacement for SN74BCT126AD in SOIC-14 packaging?
No documented pin-compatible replacement exists for SN74BCT126AD in SOIC-14 packaging. While SN74ACT126D and 74LS126D share the same 14-pin SOIC footprint and pinout, they differ electrically: ACT126 offers lower drive (24 mA IOL) and AC logic thresholds, while LS126 exhibits higher power and slower timing. Neither qualifies as a drop-in replacement without validation of timing margins, fan-out, and voltage compatibility in the target design.
Can SN74BCT126AD operate reliably at 4.5 V supply voltage?
Yes, SN74BCT126AD is fully characterized for operation at 4.5 V supply voltage, as specified in the "Recommended Operating Conditions" table (VCC MIN = 4.5 V). At this voltage, it maintains guaranteed VOH ≥ 2.4 V (IOH = –15 mA), VOL ≤ 0.55 V (IOL = 64 mA), and propagation delays within datasheet limits (e.g., tPLH ≤ 6.3 ns). System designers should ensure adequate decoupling and verify timing closure under worst-case voltage and temperature corners.
Is SN74BCT126AD compliant with RoHS and lead-free soldering standards?
Yes, SN74BCT126AD is RoHS-compliant and qualified for lead-free soldering. Per TI's packaging documentation, the SN74BCT126AD variant uses "Green (RoHS & no Sb/Br)" materials with CU NIPDAU terminations and meets JEDEC Level-1 moisture sensitivity (260°C peak reflow). The device supports standard Pb-free reflow profiles and is compatible with IPC-J-STD-020-compliant assembly processes without special handling requirements.
SN74BCT126AD Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74BCT
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 4
- Number of Bits per Element:
- 1
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74BCT126AD FAQ
1.How can I place an order for SN74BCT126AD through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74BCT126AD 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 SN74BCT126AD reliable?
The price and inventory of SN74BCT126AD are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74BCT126AD is usually 5 days.
3.What payment methods are accepted for SN74BCT126AD?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74BCT126AD transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74BCT126AD?
SN74BCT126AD orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74BCT126AD 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 SN74BCT126AD?
For technical support, including SN74BCT126AD datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74BCT126AD requirements.
6.How does Aetrix verify that SN74BCT126AD is sourced from the original manufacturer or authorized distributors?
All SN74BCT126AD 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 SN74BCT126AD meets industry standards.
7.What is the process for return or replacement of SN74BCT126AD?
All SN74BCT126AD units undergo pre-shipment inspection (PSI). If there is an issue with SN74BCT126AD, 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 SN74BCT126AD part is unused and in its original packaging.
Return procedure for SN74BCT126AD:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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