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Texas Instruments SN74AHCT126N
- Part No.:
- SN74AHCT126N
- Manufacturer:
- Texas Instruments
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AHCT126N.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,268
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Product details
Overview
SN74AHCT126N from Texas Instruments is a quadruple bus buffer gate with independent 3-state outputs, designed for bidirectional data bus isolation and level translation in 5-V digital systems. It features TTL-compatible inputs (VIH = 2 V, VIL = 0.8 V), ±25 mA output drive per channel, and operates across –40°C to +125°C. Used in PC motherboard I/O expansion, server backplane buffering, and industrial control logic interfaces.
For engineers reviewing the SN74AHCT126N datasheet, SN74AHCT126N pinout, SN74AHCT126N application, or SN74AHCT126N equivalent, key selection criteria include its 3-state enable architecture, 5-V supply compatibility, low propagation delay (1–7 ns at CL = 15 pF), and PDIP-14 package suitability for prototyping and legacy board designs.
Technical Context
The SN74AHCT126N implements four independent noninverting buffers, each with dedicated output-enable (OE) control. Each channel transitions between active drive (A → Y) and high-impedance state based solely on its OE input level-no internal latching or sequencing logic is present.
Its CMOS design with TTL-voltage thresholds enables reliable interfacing between 3.3-V logic sources and 5-V buses while maintaining noise margins of 0.7 V (VIL) and 0.6 V (VOH) under recommended conditions. Input overvoltage tolerance up to 5.5 V supports mixed-supply system robustness without external clamping.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across standard 5-V rail tolerances and brown-out resilience |
| Propagation Delay | 1 ns to 7 ns (CL = 15 pF) - enables timing-critical bus gating in sub-10-ns clock domains |
| Output Drive | ±25 mA per channel - sufficient to drive 50-Ω transmission lines or multiple 74-series loads |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - guarantees interoperability with legacy TTL and 3.3-V CMOS outputs |
| Operating Temperature | –40°C to +125°C - qualified for industrial and extended-temperature embedded applications |
| ESD Rating | 2000 V HBM - meets JEDEC JESD22-A114 for handling in standard assembly environments |
| Power Dissipation | 14 pF typical Cpd - enables low dynamic power at 1 MHz switching (≈0.7 mW @ 5 V) |
Pinout & Package
SN74AHCT126N uses a 14-pin Plastic Dual In-line Package (PDIP) with 0.3-inch body width and through-hole mounting. Pin 1 is marked by a notch or dot; leads are tin-lead (NIPDAU) finish, RoHS-compliant, and rated for manual soldering or wave soldering.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | Output Enable (1OE–4OE) | Active-high control per channel; drives Y high-impedance when low |
| 2, 5, 9, 12 | Data Input (1A–4A) | TTL-compatible input; accepts 0–5.5 V, referenced to VCC |
| 3, 6, 8, 11 | Data Output (1Y–4Y) | Noninverting buffered output; 3-state capable, ±25 mA sink/source |
| 7 | GND | Ground reference for all I/O and internal circuitry; must be low-impedance |
| 14 | VCC | 5-V power supply; requires local 0.1 µF bypass capacitor per TI layout guidelines |
Key Features
| Feature | Design Value |
|---|---|
| TTL-input compatibility | Enables direct connection to legacy 5-V TTL outputs without level-shifting circuitry |
| Independent 3-state control | Four separate OE pins allow selective bus segment isolation without affecting other channels |
| Overvoltage-tolerant inputs | Accepts up to 5.5 V regardless of VCC value, simplifying mixed-voltage interface design |
| Slow edge rate control | Reduces output ringing and EMI in unterminated or lightly loaded PCB traces |
| Latch-up immunity | Exceeds 250 mA per JESD17, ensuring robustness against transient current faults |
Applications
| PC Motherboard I/O Expansion | Industrial PLC Backplane Buffering |
|---|---|
Use Scenario: Isolating legacy ISA or LPC bus signals between southbridge and add-in cards during hot-swap or reset sequences. IC Role / Device Role / Timing Role: Bidirectional 3-state buffer enabling controlled signal routing and bus contention prevention. Use Value: Prevents data corruption during partial resets by decoupling bus segments while maintaining full 5-V logic compatibility. | Use Scenario: Interfacing microcontroller GPIOs to noisy 24-V field I/O modules via opto-isolated 5-V logic rails. IC Role / Device Role / Timing Role: Level-translating buffer isolating sensitive MCU pins from bus transients and ground bounce. Use Value: Eliminates need for discrete level shifters while providing ±25 mA drive for LED indicators and relay drivers. |
| Server Baseboard Management Controller (BMC) | Test Equipment Digital Pattern Generator |
Use Scenario: Gating SMBus or IPMI command signals between BMC and host processor during firmware updates. IC Role / Device Role / Timing Role: Controlled bus switch enabling secure, isolated communication path activation only when required. Use Value: Reduces attack surface by electrically disconnecting debug interfaces during normal operation. | Use Scenario: Driving multiple parallel test vectors into DUTs with variable load capacitance (15–50 pF). IC Role / Device Role / Timing Role: Low-skew, impedance-matched buffer stage ensuring consistent edge integrity across all 4 channels. Use Value: Maintains <7 ns max skew across channels at 50 pF, critical for synchronous multi-bit stimulus generation. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT125N | Inverting output logic (A → Y̅); identical pinout, timing, and drive capability | Required where signal polarity inversion is needed in bus control paths | Select SN74AHCT125N only when functional inversion is explicitly required; otherwise SN74AHCT126N provides direct signal pass-through. |
| 74LVC126PW | 3.3-V supply only (1.65–3.6 V); lower drive (±24 mA); different pinout (TSSOP-14) | Suitable for modern low-voltage systems but not drop-in compatible with 5-V designs | Choose 74LVC126PW only for new 3.3-V designs; SN74AHCT126N remains necessary for 5-V legacy or mixed-rail compatibility. |
Compared with SN74AHCT125N and 74LVC126PW, SN74AHCT126N uniquely delivers noninverting 5-V bus buffering with TTL input compatibility and PDIP-14 through-hole packaging-making it irreplaceable for prototyping, repair, and industrial control upgrades requiring mechanical and electrical backward compatibility.
Availability
SN74AHCT126N is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial PLC backplane buffering, and server BMC interface applications requiring stable component supply and long-term obsolescence management.
Supply support for SN74AHCT126N 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 50 years of innovation in industrial, automotive, and communications markets.
The SNx4AHCT126 family was developed to provide robust, pin-compatible 3-state bus buffers for 5-V system integration-addressing demand for TTL-compatible, high-noise-margin logic in legacy and hybrid-voltage infrastructure equipment.
FAQ
What is the maximum operating temperature range for SN74AHCT126N?
The SN74AHCT126N is rated for operation from –40°C to +125°C, making it suitable for industrial control cabinets, telecom base stations, and automotive under-hood applications where ambient temperatures exceed commercial-grade limits. This rating is validated per TI's production test flow and applies specifically to the PDIP-14 package variant SN74AHCT126N.
Does SN74AHCT126N support 3.3-V input signals?
Yes, SN74AHCT126N supports 3.3-V input signals because its VIH threshold is 2.0 V and VIL is 0.8 V-well within the 3.3-V logic high (≥2.4 V) and low (≤0.4 V) ranges. This allows direct interfacing with 3.3-V microcontrollers driving a 5-V bus, as confirmed in Section 7.3 and Figure 8-2 of the official datasheet.
Can SN74AHCT126N be used in place of SN74LS126?
SN74AHCT126N can replace SN74LS126 in most 5-V systems due to matching pinout, 3-state functionality, and TTL-compatible inputs-but with key differences: SN74AHCT126N draws significantly less quiescent current (2 µA vs. 10 mA), has faster propagation (1–7 ns vs. 15–25 ns), and requires no external pull-ups on OE pins. Always verify timing margins and load drive requirements before substitution.
What is the recommended bypass capacitor for SN74AHCT126N?
Texas Instruments recommends a 0.1 µF ceramic capacitor placed as close as possible to the VCC pin (Pin 14) and GND (Pin 7) of SN74AHCT126N to suppress high-frequency supply noise. For boards with multiple logic devices, additional bulk capacitance (e.g., 1 µF) may be added nearby, but the 0.1 µF local cap is mandatory per Section 8.3 of the datasheet.
Is SN74AHCT126N RoHS compliant?
Yes, SN74AHCT126N is RoHS compliant, with NIPDAU (nickel-palladium-gold) lead finish and no lead content exceeding EU Directive 2011/65/EU limits. This compliance is documented in TI's PACKAGE OPTION ADDENDUM (page 1, "RoHS" column = "Yes") and applies to both SN74AHCT126N and SN74AHCT126N.A orderable variants.
SN74AHCT126N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Bulk
- 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:
- Through Hole
- Supplier Device Package:
- 14-PDIP
SN74AHCT126N FAQ
1.How can I place an order for SN74AHCT126N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT126N 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 SN74AHCT126N reliable?
The price and inventory of SN74AHCT126N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT126N is usually 5 days.
3.What payment methods are accepted for SN74AHCT126N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT126N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT126N?
SN74AHCT126N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT126N 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 SN74AHCT126N?
For technical support, including SN74AHCT126N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT126N requirements.
6.How does Aetrix verify that SN74AHCT126N is sourced from the original manufacturer or authorized distributors?
All SN74AHCT126N 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 SN74AHCT126N meets industry standards.
7.What is the process for return or replacement of SN74AHCT126N?
All SN74AHCT126N units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT126N, 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 SN74AHCT126N part is unused and in its original packaging.
Return procedure for SN74AHCT126N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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