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Texas Instruments SN74AHC126D
- Part No.:
- SN74AHC126D
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AHC126D.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,190
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Product details
Overview
SN74AHC126D from Texas Instruments is a quadruple bus buffer gate with independent 3-state outputs, designed for digital signal routing and bus isolation in 2V–5.5V systems. It delivers 3.8 ns typical propagation delay at 5 V, supports ±25 mA output drive, and operates across –40°C to +85°C - enabling use in industrial control backplanes and logic-level translation between mixed-voltage subsystems.
For engineers reviewing the SN74AHC126D datasheet, SN74AHC126D pinout, SN74AHC126D application, or SN74AHC126D equivalent, key selection criteria include 3-state output timing consistency across VCC = 3.3 V and 5 V, latch-up immunity (>250 mA), and SOIC-14 package compatibility with legacy PCB layouts requiring minimal rework.
Technical Context
This device implements four identical non-inverting buffers (Y = A), each controlled by a dedicated output-enable (OE) input. All inputs are standard CMOS with ≤10 pF capacitance and defined VIH/VIL thresholds scaling with VCC - ensuring reliable operation across 2V, 3.3V, and 5V logic domains.
Each channel features balanced CMOS 3-state outputs capable of sourcing and sinking up to ±8 mA at 5 V while maintaining VOL ≤ 0.5 V and VOH ≥ 3.8 V. The high-impedance state exhibits ≤2.5 μA leakage, and thermal design is supported by RθJA = 124.6°C/W for the SOIC (D) package.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - enables interoperability across 2.5V, 3.3V, and 5V logic families without level shifters. |
| tPLH / tPHL (5 V) | 3.8 ns typical - ensures sub-4 ns signal path delay for high-speed bus enable/disable in real-time control loops. |
| IOL / IOH (5 V) | ±8 mA - drives standard TTL loads or multiple 74AHC inputs without external buffering. |
| VIH / VIL (5 V) | 3.85 V min / 1.65 V max - provides >1.3 V noise margin against ground bounce or supply ripple. |
| ICC (5.5 V) | 40 μA max - supports low-static-power operation in battery-backed or energy-constrained subsystems. |
| ESD HBM | ±2000 V - meets IEC 61000-4-2 Level 2 for board-level handling robustness during assembly. |
Pinout & Package
The SN74AHC126D uses a 14-pin SOIC (D) package with 1.27 mm pitch, 8.65 mm × 3.91 mm body size, and gull-wing leads compatible with standard reflow profiles (MSL Level-1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE, 3OE, 4OE | Independent output-enable inputs | Active-low control per channel - allows selective bus segment activation without affecting other channels. |
| 1A–4A | Buffer input terminals | CMOS-compatible inputs accepting 0–VCC logic levels; must be tied to VCC or GND if unused. |
| 1Y–4Y | Buffer output terminals | 3-state outputs with balanced drive - sink/source symmetry prevents bus contention during state transitions. |
| GND (Pin 7) | Ground reference | Common return for all internal logic and output drivers; requires low-inductance connection to system ground plane. |
| VCC (Pin 14) | Power supply | Supplies core logic and output stages; decoupling capacitor (0.1 μF ceramic) required within 5 mm of this pin. |
Key Features
| Feature | Design Value |
|---|---|
| Quadruple independent buffers | Four isolated signal paths allow concurrent enable/disable of separate data lanes - critical for multi-channel sensor interfaces. |
| 3-state output architecture | High-impedance state eliminates bus contention in shared-data applications like memory-mapped peripherals or JTAG daisy chains. |
| Wide VCC operating range | 2V–5.5V support enables direct integration into mixed-supply systems (e.g., 3.3V MCU interfacing to 5V legacy peripherals). |
| Latch-up immunity | Exceeds 250 mA per JESD17 - prevents destructive latch-up during transient overvoltage events on I/O lines. |
| Low dynamic power dissipation | 14 pF typical Cpd - minimizes switching current in high-frequency clock distribution or address bus applications. |
Applications
| Industrial Backplane Interface | Microcontroller GPIO Expansion |
|---|---|
|
Use Scenario: Isolating and driving parallel address/data buses between PLC CPU and modular I/O cards. IC Role / Device Role / Timing Role: Bus buffer with per-lane 3-state control synchronizes read/write strobes and prevents signal corruption during hot-swap insertion. Use Value: 3.8 ns propagation delay ensures setup/hold timing margins are preserved across 10 MHz bus cycles with 20 cm trace lengths. |
Use Scenario: Extending limited GPIO count of an ARM Cortex-M0+ MCU to drive 16-segment displays and status LEDs. IC Role / Device Role / Timing Role: Level-translating buffer converts 3.3V MCU outputs to 5V-compatible logic for LED anode switching. Use Value: ±8 mA drive capability directly powers common-anode displays without discrete transistors or current-limiting resistors on the display side. |
| Legacy Peripheral Interfacing | Test Equipment Signal Routing |
|
Use Scenario: Connecting modern 3.3V FPGA I/O banks to legacy 5V RS-232 transceivers or EEPROMs. IC Role / Device Role / Timing Role: Voltage-tolerant buffer isolates FPGA pins from 5V fault conditions while preserving logic polarity. Use Value: VI absolute maximum rating of 7 V protects FPGA I/Os from accidental 5V bus overvoltage during power sequencing faults. |
Use Scenario: Multiplexing calibration signals between DMM front-end ASIC and automated test fixture controllers. IC Role / Device Role / Timing Role: Channel-selectable buffer enables time-division sharing of precision reference signals among multiple DUTs. Use Value: <1.5 ns output skew (tsk(o)) ensures synchronized switching across all four channels for sub-nanosecond timing-critical measurements. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT126D | CMOS input with TTL-compatible thresholds (VIH = 2.0 V min at 5 V); slightly higher ICC (80 μA max) | Better suited for interfacing with legacy 5V TTL logic where input voltage thresholds must match 2.0 V VIH | Select SN74AHCT126D only when driving from 5V TTL outputs; otherwise SN74AHC126D offers superior noise margin and lower power. |
| 74LVC126AD | Narrower VCC range (1.65 V–3.6 V); lower drive (±24 mA at 3.3 V); smaller 14-pin TSSOP package | Optimized for ultra-low-voltage portable systems where 5V operation is unnecessary | Choose 74LVC126AD for battery-powered designs requiring <1.8 V operation; avoid for 5V bus applications due to absolute max VCC = 3.6 V. |
Compared with SN74AHCT126D and 74LVC126AD, the SN74AHC126D uniquely balances wide supply range (2–5.5 V), robust 5V tolerance, and low static current - making it the preferred choice for industrial systems with mixed-voltage domains and long-term supply stability requirements.
Availability
SN74AHC126D is available at Aetrix Electronics and suitable for industrial automation backplanes, microcontroller peripheral expansion, and legacy interface bridging requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for SN74AHC126D 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 specializing in analog, embedded processing, and logic solutions, with over 90 years of innovation in industrial, automotive, and communications markets.
The SN74AHC126D belongs to TI's advanced high-speed CMOS (AHC) logic family, engineered for low-power, high-noise-immunity digital interfacing in harsh industrial environments where reliability and voltage flexibility are critical.
FAQ
What is the maximum operating temperature range for the SN74AHC126D?
The SN74AHC126D is rated for operation from –40°C to +85°C, as confirmed in Section 5.3 Recommended Operating Conditions of the official datasheet. This industrial temperature grade makes the SN74AHC126D suitable for deployment in factory-floor controllers, motor drives, and outdoor instrumentation where ambient temperatures exceed commercial-grade limits.
Does the SN74AHC126D support 3.3V-only operation?
Yes, the SN74AHC126D fully supports 3.3V operation: VCC can be set to 3.3 V ± 0.3 V, with guaranteed switching characteristics (e.g., tPLH = 5.6 ns typical), VIH = 2.1 V min, and VOL ≤ 0.44 V at 4 mA load - all verified in Sections 5.6 and 5.3 of the datasheet.
Can unused inputs on the SN74AHC126D be left floating?
No - all unused inputs on the SN74AHC126D must be terminated to either VCC or GND, as explicitly stated in Section 5.3 Note (1) and Section 7.3.2. Floating CMOS inputs cause excessive power consumption and potential oscillation; a 10-kΩ pull-up or pull-down resistor is recommended for unconnected OE or A pins.
Is the SN74AHC126D pin-compatible with older 74LS126 devices?
No - although both are quadruple 3-state buffers, the SN74AHC126D uses CMOS technology with different DC and AC characteristics. Its input thresholds, output drive strength, and timing behavior differ significantly from bipolar 74LS126; direct replacement requires validation of voltage levels, loading, and timing margins in the target circuit.
What is the purpose of the thermal pad in the BQA package variant, and does the SN74AHC126D have one?
The thermal pad is exclusive to the WQFN (BQA) package variant and is absent in the SOIC (D) package used by the SN74AHC126D. Per Package Information tables and Figure 4-2, the SN74AHC126D has no thermal pad; its thermal performance relies solely on lead-frame conduction, with RθJA = 124.6°C/W specified for the D package.
SN74AHC126D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74AHC126D FAQ
1.How can I place an order for SN74AHC126D through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC126D 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 SN74AHC126D reliable?
The price and inventory of SN74AHC126D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC126D is usually 5 days.
3.What payment methods are accepted for SN74AHC126D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC126D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHC126D?
SN74AHC126D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC126D 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 SN74AHC126D?
For technical support, including SN74AHC126D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC126D requirements.
6.How does Aetrix verify that SN74AHC126D is sourced from the original manufacturer or authorized distributors?
All SN74AHC126D 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 SN74AHC126D meets industry standards.
7.What is the process for return or replacement of SN74AHC126D?
All SN74AHC126D units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC126D, 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 SN74AHC126D part is unused and in its original packaging.
Return procedure for SN74AHC126D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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