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Texas Instruments SN74AHCT126DR
- Part No.:
- SN74AHCT126DR
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AHCT126DR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:8,134
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Product details
Overview
SN74AHCT126DR from Texas Instruments is a quadruple 3-state bus buffer gate IC with TTL-compatible inputs, designed for bidirectional data bus isolation and level translation in 5-V digital systems. It features four independent noninverting buffers (1A→1Y, 2A→2Y, 3A→3Y, 4A→4Y), each controlled by its own output-enable (OE) input, with 8 mA output drive capability, 7 ns typical propagation delay at 5 V, and operation across –40°C to +125°C.
For engineers reviewing the SN74AHCT126DR datasheet, SN74AHCT126DR pinout, SN74AHCT126DR application, or SN74AHCT126DR equivalent, this page delivers verified functional identity, SOIC-14 package mapping, confirmed 3-state bus buffering role, real-world timing and drive specs, and two validated alternative parts for system-level design continuity.
Technical Context
The SN74AHCT126DR implements four independent CMOS buffer channels, each with a dedicated active-high output-enable control line. Its TTL-voltage-compatible inputs (VIH = 2 V, VIL = 0.8 V) enable reliable interfacing with legacy 3.3-V logic while operating at 5-V VCC, supporting up-translation without external biasing.
Each channel operates in one of three defined states: high (VOH ≥ 3.8 V @ IOL = 8 mA), low (VOL ≤ 0.44 V @ IOL = 8 mA), or high-impedance (IOZ ≤ ±2.5 µA), with fast enable/disable transitions (tPZH/tPLZ ≤ 6.5 ns) and low dynamic noise (VOL(P) ≤ 0.8 V, VOH(V) ≥ 4.4 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures stable operation under standard 5-V rail tolerances and brown-out immunity |
| Output Drive | ±8 mA - sufficient for driving multiple CMOS loads or short PCB traces without signal integrity degradation |
| Propagation Delay | 1 ns to 7 ns (CL = 15 pF) - enables timing-critical bus gating in high-speed digital subsystems |
| Input Compatibility | TTL-level (VIH = 2 V, VIL = 0.8 V) - allows direct connection to 3.3-V microcontrollers and FPGAs without level shifters |
| Operating Temp | –40°C to +125°C - supports industrial and extended-temperature embedded applications |
| ESD Rating | 2000 V HBM - meets JEDEC JS-001 requirements for robust handling in manufacturing and field environments |
| Power Dissipation | 14 pF Cpd - low dynamic power consumption during switching, reducing thermal load in dense layouts |
Pinout & Package
SN74AHCT126DR is supplied in a 14-pin SOIC (D) package with standard 1.27-mm pitch, 8.65-mm body width, and gull-wing leads. Pin 1 is located at the top-left corner adjacent to the index notch or dot marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | Output Enable (1OE, 2OE, 3OE, 4OE) | Active-high control lines - each independently places corresponding Y output into high-Z state when low |
| 2, 5, 9, 12 | Input (1A, 2A, 3A, 4A) | Noninverting data inputs - accept TTL-compatible signals and pass through to respective Y outputs when OE is high |
| 3, 6, 8, 11 | Output (1Y, 2Y, 3Y, 4Y) | 3-state buffered outputs - drive high/low or present >10⁶ Ω impedance based on OE status and A input |
| 7 | GND | Ground reference for all internal circuitry and output current return path |
| 14 | VCC | Primary 5-V supply - powers all four buffer channels and OE logic; requires local 0.1-µF bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| TTL-input compatibility | Enables direct interface with 3.3-V logic families while operating at 5-V VCC, eliminating need for external level translators |
| Independent 3-state control | Four separate OE pins allow selective bus segment isolation - critical for multi-master arbitration and hot-swap readiness |
| Low-output ringing | Controlled edge rates (Δt/Δv = 20 ns/V) minimize overshoot/undershoot on unterminated traces, improving signal integrity |
| High-impedance power-up state | Outputs default to high-Z when OE is unasserted or floating, preventing bus contention during reset or initialization |
| Industrial temperature range | Guaranteed functionality from –40°C to +125°C supports deployment in automotive ECUs, industrial PLCs, and telecom base stations |
Applications
| Server Backplane Interfacing | Industrial PLC I/O Expansion |
|---|---|
Use Scenario: Isolating control signals between CPU module and hot-pluggable I/O cards in modular server chassis. IC Role / Device Role / Timing Role: Bus buffer providing direction-controlled, 3-state isolation between backplane data lanes and card-local logic. Use Value: Prevents bus contention during card insertion/removal and ensures clean signal transition via TTL-compatible input thresholds. |
Use Scenario: Expanding digital input/output capacity in programmable logic controllers using standardized 24-V field wiring. IC Role / Device Role / Timing Role: Level-translating buffer converting 3.3-V FPGA I/O to 5-V tolerant bus segments connected to opto-isolated inputs. Use Value: Enables seamless integration of modern low-voltage FPGAs into legacy 5-V industrial control architectures without added voltage translation ICs. |
| Network Switch Data Path Gating | Wearable Health Sensor Hub Interface |
Use Scenario: Enabling/disabling parallel data paths between MAC controller and PHY transceivers in Gigabit Ethernet switches. IC Role / Device Role / Timing Role: Quad-gate buffer with per-channel OE control managing clock-aligned data flow across isolated switch fabric segments. Use Value: Delivers sub-7-ns propagation delay and precise enable timing to maintain deterministic latency in time-sensitive packet forwarding paths. |
Use Scenario: Aggregating sensor data from multiple low-power analog front-ends (ECG, SpO₂, accelerometer) into a single 5-V microcontroller bus. IC Role / Device Role / Timing Role: Low-noise, 3-state bus buffer isolating sensor interface domain from main MCU domain during sleep mode. Use Value: Reduces dynamic noise (VOL(P) ≤ 0.8 V) to preserve signal fidelity of microvolt-level biomedical waveforms during concurrent digital activity. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC126A | 3.3-V only supply (1.65–3.6 V), lower drive (±24 mA), faster tPD (3.7 ns), no TTL input compatibility | Requires 3.3-V system architecture; unsuitable for 5-V mixed-voltage designs or legacy TTL interfacing | Select when full 3.3-V operation and higher speed are prioritized over voltage translation capability |
| SN74AHCT244N | Octal (8-channel) configuration, same VCC range and TTL compatibility, identical SOIC-20 package | Provides double the channel count but requires larger PCB footprint and different pinout; not drop-in compatible | Choose when system demands more than four isolated bus segments and board layout permits SOIC-20 placement |
Compared with SN74LVC126A and SN74AHCT244N, the SN74AHCT126DR uniquely balances 5-V operation, TTL input compatibility, and compact 14-pin SOIC packaging-making it optimal for space-constrained, mixed-voltage bus isolation where precise 3-state control of exactly four lines is required.
Availability
SN74AHCT126DR is available at Aetrix Electronics and suitable for industrial PLCs, network switch data paths, server backplane interfaces, and wearable health sensor hubs requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN74AHCT126DR 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 decades of expertise in high-reliability logic families and industrial-grade interface ICs.
The SN74AHCT126DR belongs to TI's AHCT logic family, engineered specifically for 5-V systems requiring TTL-compatible inputs, robust 3-state bus control, and guaranteed operation across industrial temperature extremes.
FAQ
What is the function of the OE pins on the SN74AHCT126DR?
Each OE pin (1OE, 2OE, 3OE, 4OE) is an active-high output-enable control for its corresponding buffer channel. When low, the associated Y output enters high-impedance state; when high, the Y output follows the A input. This allows independent gating of four data lines. The SN74AHCT126DR uses this architecture to prevent bus contention in multi-drop systems and support hot-swap functionality without external logic.
Can the SN74AHCT126DR operate with a 3.3-V supply?
No - the SN74AHCT126DR is specified only for 4.5 V to 5.5 V VCC operation. Its internal circuitry and TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V) are optimized for 5-V systems. For 3.3-V operation, TI recommends the SN74LVC126A instead. Using the SN74AHCT126DR below 4.5 V may result in undefined output states or failure to meet timing specifications.
Does the SN74AHCT126DR require pull-up or pull-down resistors on unused OE pins?
Yes - all unused OE pins must be tied to either VCC or GND to prevent floating inputs, which could cause unpredictable output behavior or increased ICC. TI recommends connecting unused OE pins directly to GND to ensure the corresponding outputs remain in high-Z state. This practice is explicitly stated in the device functional modes section of the SN74AHCT126DR datasheet.
What is the maximum capacitive load the SN74AHCT126DR can drive reliably?
The SN74AHCT126DR is characterized for CL = 15 pF and 50 pF loads in its switching characteristics table. At 50 pF, tPLH/tPHL remains ≤9.5 ns and tPZH/tPLZ ≤9 ns, confirming reliable operation up to 50 pF. Driving heavier loads may increase propagation delay and output rise/fall times beyond specification limits. For loads exceeding 50 pF, consider adding series termination or selecting a higher-drive buffer such as the SN74AHCT244N.
Is the SN74AHCT126DR pin-compatible with other members of the SN74AHCTxx family?
No - the SN74AHCT126DR has a unique 14-pin SOIC pinout specific to its quad-buffer-with-OE function. While other AHCT devices like SN74AHCT00 (quad NAND) or SN74AHCT04 (hex inverter) share the same package outline, their pin assignments differ significantly. The SN74AHCT126DR pinout is defined in Figure 4-1 and Table 4-1 of its datasheet and is not interchangeable with any other AHCT part number without redesigning the PCB layout.
SN74AHCT126DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74AHCT126DR FAQ
1.How can I place an order for SN74AHCT126DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT126DR 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 SN74AHCT126DR reliable?
The price and inventory of SN74AHCT126DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT126DR is usually 5 days.
3.What payment methods are accepted for SN74AHCT126DR?
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4.How is shipping managed for SN74AHCT126DR?
SN74AHCT126DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT126DR 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 SN74AHCT126DR?
For technical support, including SN74AHCT126DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT126DR requirements.
6.How does Aetrix verify that SN74AHCT126DR is sourced from the original manufacturer or authorized distributors?
All SN74AHCT126DR 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 SN74AHCT126DR meets industry standards.
7.What is the process for return or replacement of SN74AHCT126DR?
All SN74AHCT126DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT126DR, 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 SN74AHCT126DR part is unused and in its original packaging.
Return procedure for SN74AHCT126DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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