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Texas Instruments SN74AHCT126PW
- Part No.:
- SN74AHCT126PW
- Manufacturer:
- Texas Instruments
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AHCT126PW.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:10,795
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Product details
Overview
SN74AHCT126PW 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 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 and server backplane interface logic.
For engineers reviewing the SN74AHCT126PW datasheet, SN74AHCT126PW pinout, SN74AHCT126PW application, or SN74AHCT126PW equivalent, key selection criteria include 3-state timing (tPZH/tPLZ ≤ 6.5 ns at CL = 15 pF), latch-up immunity (>250 mA), and compatibility with mixed-voltage 3.3-V/5-V signal domains.
Technical Context
The SN74AHCT126PW implements four independent noninverting buffers, each with dedicated output-enable (OE) control. Each channel transitions to high-impedance when its OE is low, enabling bus sharing without contention. Input thresholds are optimized for TTL-level compatibility while operating from a 4.5–5.5 V supply.
Its CMOS architecture delivers low static current (ICC ≤ 20 µA), controlled edge rates (Δt/Δv ≤ 20 ns/V) to suppress ringing, and robust ESD protection (2000 V HBM). The device supports hot-swap-safe power-up sequencing via OE pull-down recommendations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across industrial-grade 5-V rail tolerances |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - guarantees reliable recognition of TTL logic levels from legacy or mixed-voltage sources |
| Output Drive | ±8 mA at VOH/VOL - sufficient for driving standard 50-pF loads and multiple CMOS inputs without external buffering |
| Propagation Delay | tPLH/tPHL ≤ 7 ns (CL = 15 pF) - enables use in sub-100-MHz digital control and address/data bus paths |
| 3-State Enable Time | tPZH/tPLZ ≤ 6.5 ns (CL = 15 pF) - allows fast bus arbitration and dynamic resource sharing in multiprocessor systems |
| ESD Rating | 2000 V HBM - meets JEDEC JS-001 requirements for handling in standard assembly environments |
| Latch-up Immunity | >250 mA per JESD 17 - prevents destructive latch-up during transient overvoltage events on I/O lines |
Pinout & Package
TSSOP-14 (PW) package: 4.4 mm × 5.0 mm body, 0.65 mm pitch, exposed pad not present, RoHS-compliant NiPdAu lead finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | OE1, OE2, OE3, OE4 | Active-high output enable for each buffer - tie low to disable output and isolate bus segment |
| 2, 5, 9, 12 | A1, A2, A3, A4 | Noninverting input - accepts TTL- or CMOS-level signals; overvoltage tolerant to 5.5 V |
| 3, 6, 8, 11 | Y1, Y2, Y3, Y4 | 3-state buffered output - high-impedance when corresponding OE is low; drives up to ±25 mA |
| 7 | GND | Ground reference - must be connected to system ground plane for noise immunity and thermal stability |
| 14 | VCC | Power supply - requires local 0.1 µF bypass capacitor placed within 3 mm of pin for clean switching operation |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Enables direct interfacing with legacy 5-V TTL logic without level-shifting circuitry |
| Independent 3-state control | Four separate OE pins allow granular bus management - only active channels load the bus |
| Slow edge rate control | Reduces output ringing and EMI in high-speed PCB traces, especially under light capacitive loads |
| Overvoltage-tolerant inputs | Accepts VI up to 5.5 V regardless of VCC setting - simplifies mixed-rail system integration |
| High latch-up immunity | Withstands >250 mA transient currents per JESD 17 - improves reliability in noisy industrial environments |
Applications
| PC Motherboard I/O Expansion | Server Backplane Interface |
|---|---|
Use Scenario: Isolating legacy parallel port, PS/2, or LPC bus signals between southbridge and peripheral headers. IC Role / Device Role / Timing Role: Bidirectional buffer with per-channel 3-state control to prevent bus contention during hot-plug events. Use Value: Eliminates need for discrete pull-up/pull-down networks and reduces routing complexity on dense motherboard layers. |
Use Scenario: Managing shared control/status lines between baseboard management controller (BMC) and modular compute blades. IC Role / Device Role / Timing Role: Signal repeater and bus isolator ensuring timing integrity across 150-mm backplane traces. Use Value: Maintains <7 ns propagation delay and <6.5 ns 3-state transition, preserving setup/hold margins in multi-drop configurations. |
| Industrial PLC I/O Module | Network Switch Control Plane |
Use Scenario: Buffering digital input/output signals between microcontroller GPIO and field-side optocouplers or relay drivers. IC Role / Device Role / Timing Role: Level-translating interface that accepts 3.3-V MCU outputs and drives 5-V industrial logic rails. Use Value: TTL-compatible thresholds and 4.5–5.5 V operation ensure interoperability with both modern MCUs and legacy 5-V peripherals. |
Use Scenario: Enabling/disabling configuration buses (e.g., SMBus, MDIO) between switch ASIC and PHY management interfaces. IC Role / Device Role / Timing Role: Bus keeper and contention guard - OE pins synchronized with ASIC reset assertion to avoid floating states. Use Value: Prevents undefined logic states during power sequencing, reducing firmware initialization failures in carrier-grade switches. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT125PW | Quad buffer with inverted outputs (A → Y̅); identical timing, voltage, and packaging | Required where active-low output polarity is needed for enable/disable signaling or LED sinking | Select SN74AHCT125PW only when inversion is functionally required - not a drop-in replacement |
| SN74LVC126APW | Lower VCC range (1.65–3.6 V), 3.3-V logic family; 24 mA drive, faster tPD (~3.5 ns) | Suitable for 3.3-V-only systems; incompatible with 5-V buses without level shifters | Choose SN74LVC126APW for new 3.3-V designs prioritizing speed and lower power; not interchangeable with SN74AHCT126PW |
Compared with SN74AHCT126PW, SN74AHCT125PW provides inverted logic polarity but identical timing and drive strength, while SN74LVC126APW targets 3.3-V domains with higher speed but no 5-V tolerance - neither offers pin-to-pin or functional equivalence without circuit redesign.
Availability
SN74AHCT126PW is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, server backplane interface, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges.
Supply support for SN74AHCT126PW 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 SNx4AHCT logic family delivers TTL-compatible 5-V CMOS buffers optimized for bus isolation, level translation, and noise-immune signal routing in high-reliability computing infrastructure.
FAQ
What is the operating temperature range for SN74AHCT126PW?
The SN74AHCT126PW is rated for operation from –40°C to +125°C, making it suitable for industrial and extended-temperature applications such as server backplanes and programmable logic controllers. This range is confirmed in Section 5.3 of the official datasheet under Recommended Operating Conditions for the commercial-grade SN74AHCT126 variant in PW packaging.
Does SN74AHCT126PW support 3.3-V input signals?
Yes, SN74AHCT126PW accepts 3.3-V logic inputs reliably due to its TTL-compatible input thresholds (VIH = 2.0 V, VIL = 0.8 V). When powered at 5 V, it functions as a 3.3-V-to-5-V translator - a key use case documented in Section 8.2.1 and Figure 8-2 of the datasheet.
What is the maximum output current per channel for SN74AHCT126PW?
The SN74AHCT126PW supports ±25 mA continuous output current per channel (IOL/IOH), as specified in Section 5.1 Absolute Maximum Ratings. However, for guaranteed performance across temperature, the recommended operating condition limits output current to ±8 mA (Section 5.3).
Is SN74AHCT126PW pin-compatible with other AHCT126 variants?
Yes - all SN74AHCT126 variants (e.g., SN74AHCT126DR, SN74AHCT126DBR) share identical pinout and function mapping per Table 4-1. The PW package uses the same 14-pin TSSOP footprint and terminal assignments as defined for SN74AHCT126 in D, DB, and NS packages.
How should unused inputs be handled on SN74AHCT126PW?
All unused inputs on SN74AHCT126PW must be tied to VCC or GND to prevent floating states and potential increased ICC or oscillation. Section 8.4.1 explicitly states this requirement, and TI Application Report SCBA004 details best practices for biasing CMOS inputs in unused gates.
SN74AHCT126PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 14-TSSOP (0.173", 4.40mm 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:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-TSSOP
SN74AHCT126PW FAQ
1.How can I place an order for SN74AHCT126PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT126PW 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 SN74AHCT126PW reliable?
The price and inventory of SN74AHCT126PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT126PW is usually 5 days.
3.What payment methods are accepted for SN74AHCT126PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT126PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT126PW?
SN74AHCT126PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT126PW 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 SN74AHCT126PW?
For technical support, including SN74AHCT126PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT126PW requirements.
6.How does Aetrix verify that SN74AHCT126PW is sourced from the original manufacturer or authorized distributors?
All SN74AHCT126PW 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 SN74AHCT126PW meets industry standards.
7.What is the process for return or replacement of SN74AHCT126PW?
All SN74AHCT126PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT126PW, 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 SN74AHCT126PW part is unused and in its original packaging.
Return procedure for SN74AHCT126PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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