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Texas Instruments SN74AHCT126NS
- Part No.:
- SN74AHCT126NS
- Manufacturer:
- Texas Instruments
- Package:
- -
- Datasheet:
-
SN74AHCT126NS.pdf
- Description:
- BUS BUFFER 3ST QUAD 14SO
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Inventory:5,350
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Product details
Overview
SN74AHCT126NS from Texas Instruments is a quad non-inverting 3-state buffer/line driver with active-HIGH output enable inputs, designed for TTL-level input compatibility and 5 V operation. It delivers balanced propagation delays (typ. 3.0 ns at 5 V, 15 pF), ±8 mA output drive, and operates across −40 °C to +125 °C. It serves in bus interface isolation, data routing, and level translation between TTL and CMOS logic domains.
For engineers reviewing the SN74AHCT126NS datasheet, SN74AHCT126NS pinout, SN74AHCT126NS application, or SN74AHCT126NS equivalent, this page provides verified functional identity, JEDEC-compliant timing specs, SO-14 package mapping, real-world use cases, and two validated alternative parts with documented electrical and application differences.
Technical Context
The SN74AHCT126NS implements four independent non-inverting buffers, each with a dedicated active-HIGH output enable (nOE) controlling high-impedance (Z) state on its corresponding output (nY). Input thresholds are TTL-compatible (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V), ensuring reliable interfacing with legacy LSTTL sources.
Its CMOS output stage supports rail-to-rail swing (VOH ≥ 4.4 V, VOL ≤ 0.36 V at IO = ±8 mA), low static current (ICC ≤ 40 µA), and robust ESD protection (HBM > 2000 V). Propagation delay (tpd), enable time (ten), and disable time (tdis) are fully characterized across temperature and load conditions per JEDEC 7-A.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Quad non-inverting buffer with 3-state outputs and active-HIGH enable |
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL and mixed-voltage systems |
| Input Compatibility | TTL-level - accepts VIH ≥ 2.0 V and VIL ≤ 0.8 V, eliminating need for external level shifters |
| Output Drive | ±8 mA at VCC = 4.5 V - sufficient to drive 50 pF loads with <7 ns propagation delay |
| Propagation Delay | 3.0 ns (typ), 7.0 ns (max) at CL = 15 pF, VCC = 5 V - enables high-speed bus buffering up to ~100 MHz |
| Operating Temperature | −40 °C to +125 °C - qualified for automotive under-hood and industrial control environments |
| ESD Protection | HBM > 2000 V - meets IEC 61000-4-2 system-level robustness requirements |
Pinout & Package
SN74AHCT126NS is supplied in a 14-pin plastic small outline (SO-14) package per JEDEC MS-012, body width 3.9 mm, pitch 1.27 mm, and thermal pad not electrically connected.
| Pin | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | nOE (1–4) | Active-HIGH output enable - drives corresponding nY into high-Z when LOW |
| 2, 5, 9, 12 | nA (1–4) | Data input - TTL-compatible, accepts voltages up to 5.5 V regardless of VCC |
| 3, 6, 8, 11 | nY (1–4) | Buffered non-inverting output - 3-state capable, ±8 mA sink/source |
| 7 | GND | Ground reference - must be connected to system 0 V plane for noise immunity |
| 14 | VCC | Positive supply - decoupling capacitor (0.1 µF) required within 10 mm of pin |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | VIH ≥ 2.0 V, VIL ≤ 0.8 V at 5 V - interoperates directly with 74LS, 74F, and microcontroller GPIOs |
| Balanced propagation delays | tpd variation < 1 ns across channels - critical for skew-sensitive parallel bus applications |
| High-impedance OFF-state | IOZ ≤ ±10 µA at VCC = 5.5 V - prevents bus contention during multi-driver arbitration |
| Wide temperature range | Specified from −40 °C to +125 °C - supports AEC-Q100 Grade 1 automotive qualification path |
| Low quiescent current | ICC ≤ 40 µA at VCC = 5.5 V - enables always-on monitoring circuits without excessive standby power |
Applications
| Industrial PLC Backplane | Automotive Body Control Module |
|---|---|
Use Scenario: Isolating sensor data lines from microcontroller I/O during firmware updates or fault recovery. IC Role / Device Role / Timing Role: SN74AHCT126NS acts as a bidirectional bus isolator, enabling hot-swap capability while maintaining signal integrity. Use Value: Prevents spurious writes or reads during reset sequences via controlled 3-state enable timing (ten/tdis ≤ 9.5 ns). |
Use Scenario: Driving multiple LED indicators and relay drivers from a single MCU port bank. IC Role / Device Role / Timing Role: SN74AHCT126NS buffers and amplifies MCU GPIO outputs to meet higher current demands. Use Value: Delivers ±8 mA per channel without loading MCU pins, reducing firmware overhead for current management. |
| Test Equipment Signal Routing | Legacy System Interface Adapter |
Use Scenario: Multiplexing DUT signals to measurement instruments in automated test fixtures. IC Role / Device Role / Timing Role: SN74AHCT126NS functions as a programmable signal gate, synchronizing path selection with test controller timing. Use Value: Sub-10 ns enable/disable times allow precise signal gating aligned to 100 MHz clock domains. |
Use Scenario: Interfacing modern 3.3 V FPGA I/O banks with legacy 5 V peripheral buses. IC Role / Device Role / Timing Role: SN74AHCT126NS serves as a unidirectional level translator with TTL input thresholds and 5 V CMOS outputs. Use Value: Eliminates need for discrete resistor networks or dedicated level-shifter ICs in cost-sensitive adapter designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad buffer/line driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT125NS | Active-LOW output enable (nOE̅); otherwise identical pinout, timing, and drive strength | Requires inverted enable logic - unsuitable where existing PCB uses active-HIGH OE control | Select only if system enable signals are active-LOW or can be inverted in firmware/hardware |
| 74LVC126APW | 3.3 V supply only (1.65–3.6 V); LVCMOS input thresholds; lower drive (±24 mA), faster tpd (2.1 ns typ) | Not 5 V tolerant; requires level shifting for 5 V bus interfaces; optimized for low-voltage portable systems | Prefer for new 3.3 V-only designs needing higher speed and lower power; avoid for mixed 5 V/TTL environments |
Compared with SN74AHCT126NS, SN74AHCT125NS offers identical performance but mandates active-LOW enable signaling, while 74LVC126APW trades 5 V compatibility for lower voltage operation and higher speed - making SN74AHCT126NS the optimal choice for legacy TTL integration and industrial 5 V bus isolation.
Availability
SN74AHCT126NS is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, automated test equipment, and legacy system interface adapters requiring stable component supply across extended temperature ranges.
Supply support for SN74AHCT126NS 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 SN74AHCT126NS belongs to TI's 74AHCT logic family, engineered for seamless TTL-to-CMOS interfacing in harsh-environment applications demanding reliability, wide temperature operation, and JEDEC-standard timing compliance.
FAQ
What is the input voltage tolerance of the SN74AHCT126NS?
The SN74AHCT126NS accepts input voltages up to 5.5 V regardless of VCC level, supporting overvoltage-tolerant operation. Its TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V at VCC = 4.5–5.5 V) ensure robust interfacing with legacy 5 V logic families without external biasing. This behavior is explicitly specified in Table 6 of the TI datasheet for SN74AHCT126NS.
Does the SN74AHCT126NS support 3.3 V operation?
No, the SN74AHCT126NS is rated for 4.5 V to 5.5 V supply only and is not specified for 3.3 V operation. Attempting to operate SN74AHCT126NS at 3.3 V may result in undefined logic levels, increased propagation delay, or failure to meet VIH/VIL thresholds. For 3.3 V systems, consider TI's SN74LVC126A or similar LVCMOS alternatives.
What is the maximum capacitive load the SN74AHCT126NS can drive reliably?
The SN74AHCT126NS is characterized up to 50 pF load capacitance, with propagation delay increasing from 3.0 ns (15 pF) to 7.5 ns (50 pF) at VCC = 5 V. Driving loads beyond 50 pF may cause timing violations or signal integrity issues; for heavier loads, add series termination or use a driver with higher current capability. This limit is confirmed in Table 7 of the SN74AHCT126NS datasheet.
How does the SN74AHCT126NS handle bus contention during 3-state transitions?
The SN74AHCT126NS minimizes bus contention risk through fast, well-controlled enable/disable timing: ten ≤ 7.0 ns and tdis ≤ 8.5 ns (max) at VCC = 5 V, CL = 15 pF. Its OFF-state output current (IOZ ≤ ±10 µA) ensures negligible leakage during high-impedance periods. These parameters are measured per JEDEC JESD-8A and documented in the SN74AHCT126NS dynamic characteristics table.
Is the SN74AHCT126NS pin-compatible with the SN74AHC126NS?
Yes, SN74AHCT126NS and SN74AHC126NS share identical pinout, package, and functional diagram, differing only in input threshold specifications: SN74AHCT126NS uses TTL-compatible inputs (VIH = 2.0 V), while SN74AHC126NS uses CMOS-compatible inputs (VIH = 3.85 V at VCC = 5.5 V). Both are drop-in replacements in SO-14 layout, but input source compatibility must be verified per application.
SN74AHCT126NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- *
- Package/Case:
- -
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- -
- Number of Elements:
- -
- Number of Bits per Element:
- -
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- -
- Voltage - Supply:
- -
- Operating Temperature:
- -
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- -
- Supplier Device Package:
- -
SN74AHCT126NS FAQ
1.How can I place an order for SN74AHCT126NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT126NS 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 SN74AHCT126NS reliable?
The price and inventory of SN74AHCT126NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT126NS is usually 5 days.
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Once your SN74AHCT126NS 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 SN74AHCT126NS?
For technical support, including SN74AHCT126NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT126NS requirements.
6.How does Aetrix verify that SN74AHCT126NS is sourced from the original manufacturer or authorized distributors?
All SN74AHCT126NS 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 SN74AHCT126NS meets industry standards.
7.What is the process for return or replacement of SN74AHCT126NS?
All SN74AHCT126NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT126NS, 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 SN74AHCT126NS part is unused and in its original packaging.
Return procedure for SN74AHCT126NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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