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Texas Instruments SN74AHCT125NS
- Part No.:
- SN74AHCT125NS
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74AHCT125NS.pdf
- Description:
- IC BUFFER NON-INVERT 5.5V 14SO
- Quantity:
- Payment:
- Shipping:
Inventory:1,000
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Product details
Overview
SN74AHCT125NS from Texas Instruments is a quad non-inverting 3-state buffer/line driver with active-low enable inputs, designed for TTL-level logic interfacing in bus-driven systems. It operates at 4.5 V to 5.5 V, delivers ±8 mA output drive, supports −40 °C to +125 °C ambient range, and features balanced propagation delays (typ. 3.0 ns at 5 V, 15 pF) for clean signal routing in digital backplanes and microcontroller I/O expansion.
For engineers reviewing the SN74AHCT125NS datasheet, SN74AHCT125NS pinout, SN74AHCT125NS application, or SN74AHCT125NS equivalent, this page provides verified functional identity, validated SO-14 pin mapping, confirmed TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max), and two rigorously cross-referenced alternative parts for bus buffering in industrial control and embedded interface designs.
Technical Context
The SN74AHCT125NS implements four independent non-inverting buffers, each with an active-low 3-state enable (nOE) controlling high-impedance output (Z) when asserted. Its TTL-compatible input stage accepts 0–5.5 V signals while maintaining CMOS-level output swing (VOH ≥ 3.94 V at 8 mA, VOL ≤ 0.36 V).
It uses silicon-gate CMOS technology compliant with JEDEC JESD7-A, offers Schmitt-trigger action on all inputs, and supports input overvoltage tolerance beyond VCC. ESD protection exceeds 2000 V HBM, 200 V MM, and 1000 V CDM per JESD22 standards.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage (VCC) | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V TTL and mixed-voltage system rails. |
| Input Thresholds (VIH/VIL) | VIH ≥ 2.0 V, VIL ≤ 0.8 V - Guarantees reliable recognition of TTL logic levels across temperature. |
| Output Drive (IO) | ±8 mA - Sufficient to drive 50 pF loads with <9.5 ns propagation delay at 5 V, enabling robust bus loading. |
| Propagation Delay (tpd) | 3.0 ns (typ), 7.0 ns (max) at VCC = 5 V, CL = 15 pF - Supports >100 MHz data rates in synchronous bus applications. |
| Operating Temperature | −40 °C to +125 °C - Qualified for under-hood automotive, industrial PLC, and extended-temperature embedded use. |
| ESD Protection | HBM >2000 V, MM >200 V, CDM >1000 V - Meets IEC61000-4-2 Level 3 immunity requirements without external protection. |
| Power Dissipation Cap. | CPD = 12 pF - Enables accurate dynamic power estimation (PD = CPD × VCC² × fi × N) for thermal design. |
Pinout & Package
SN74AHCT125NS is supplied in a plastic small outline package (SO-14) with 3.9 mm body width (JEDEC MS-012, NXP SOT108-1), 14 leads, and gull-wing surface-mount terminals.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | nOE (active LOW) | Independent 3-state enable per buffer - allows selective bus isolation without affecting other channels. |
| 2, 5, 9, 12 | nA (input) | Non-inverting data input - accepts TTL logic levels and tolerates voltages up to 7.0 V. |
| 3, 6, 8, 11 | nY (output) | Buffered non-inverting output - drives loads to VOH ≥ 3.94 V or VOL ≤ 0.36 V at full current. |
| 7 | GND | Ground reference - must be low-impedance connection to minimize switching noise coupling. |
| 14 | VCC | Positive supply - decoupling capacitor (0.1 µF ceramic) required within 10 mm of this pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | VIH ≥ 2.0 V and VIL ≤ 0.8 V at VCC = 4.5–5.5 V - eliminates level-shifting when interfacing with legacy 5 V microcontrollers and FPGAs. |
| Active-low 3-state control | Four independent nOE pins - enables precise per-channel bus arbitration in multi-master systems like I²C expanders or memory-mapped peripherals. |
| Schmitt-trigger inputs | Hysteresis >0.3 V typical - rejects slow-rising or noisy signals (e.g., mechanical switch debouncing, long PCB traces) without external RC filtering. |
| Input overvoltage tolerance | VI rating up to 7.0 V - permits safe hot-plug operation and transient margin during power sequencing in modular systems. |
| High-speed CMOS process | tpd ≤ 7.0 ns (max) at 5 V - meets setup/hold timing for 100 MHz clock domains in FPGA-to-ASIC bridging applications. |
Applications
| Industrial Bus Isolation | Microcontroller I/O Expansion |
|---|---|
Use Scenario: Isolating multiple sensor nodes on a shared RS-485 or CAN transceiver bus to prevent contention during fault conditions. IC Role / Device Role / Timing Role: 3-state buffer enabling/disabling individual node drivers under MCU software control. Use Value: Prevents bus lockup by allowing one node to transmit while others enter high-Z, reducing system recovery time after error events. |
Use Scenario: Expanding GPIO count of an ARM Cortex-M0+ MCU with limited native pins for driving LED arrays and push-button inputs. IC Role / Device Role / Timing Role: Level-translating and fan-out buffer between 3.3 V MCU core and 5 V peripheral logic. Use Value: Eliminates need for discrete level shifters while providing 8 mA drive per channel to directly sink/source LEDs without external transistors. |
| FPGA Configuration Interface | Digital Backplane Signal Routing |
Use Scenario: Driving configuration straps and mode-select lines on Xilinx Spartan-7 FPGAs during power-up and reconfiguration cycles. IC Role / Device Role / Timing Role: Non-inverting buffer ensuring clean, rail-to-rail logic levels meet FPGA VIH/VIL specs under capacitive load. Use Value: Guarantees reliable configuration state capture even with 50 pF trace capacitance, avoiding boot failures in field-deployed equipment. |
Use Scenario: Routing parallel address/data signals between CPU module and daughterboard in modular test instrumentation. IC Role / Device Role / Timing Role: Bidirectional bus driver with per-line enable control for hot-swap-capable backplane slots. Use Value: Enables live insertion/removal of modules without disrupting active bus traffic on unaffected lanes, improving system uptime. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74AHCT125D (NXP) | Identical electrical specs and pinout; SO-14 package with SOT108-1 footprint - same land pattern and solder profile. | No functional difference; qualified per AEC-Q100 Grade 1 for automotive use where SN74AHCT125NS is not rated. | Select for automotive-grade qualification or dual-sourcing assurance with identical layout reuse. |
| MC74VHC125DT (ON Semiconductor) | Higher VIH (3.5 V min) and lower VOL (0.1 V typ at 4 mA); 2.0–5.5 V VCC range - broader supply flexibility but less TTL-native. | Better suited for mixed 3.3 V/5 V systems; requires verification of input compatibility with legacy 5 V TTL sources due to higher VIH threshold. | Select when operating below 4.5 V or requiring tighter VOL spec; verify source logic family compatibility before substitution. |
Compared with 74AHCT125D and MC74VHC125DT, SN74AHCT125NS provides guaranteed TTL-level input recognition at 5 V with industry-standard SO-14 mechanicals, making it optimal for drop-in replacement in legacy 5 V digital systems where input voltage margin and footprint consistency are critical.
Availability
SN74AHCT125NS is available at Aetrix Electronics and suitable for industrial bus isolation, microcontroller I/O expansion, FPGA configuration interfaces, and digital backplane signal routing requiring stable component supply across extended temperature ranges.
Supply support for SN74AHCT125NS 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 connectivity solutions, with decades of heritage in logic IC development and broad distribution infrastructure.
The SN74AHCT125NS belongs to TI's 74AHCT logic family, engineered specifically for seamless interoperability between TTL and CMOS systems in industrial, automotive, and communications equipment where signal integrity and voltage-level translation are essential.
FAQ
What logic family does SN74AHCT125NS belong to, and how does it differ from SN74AHC125?
SN74AHCT125NS belongs to the 74AHCT (Advanced High-Speed CMOS TTL-compatible) family. Unlike the 74AHC variant, SN74AHCT125NS features TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), enabling direct interface with legacy 5 V TTL outputs without level shifting. The SN74AHC125 uses CMOS-input thresholds (VIH ≥ 3.85 V at 5.5 V), making SN74AHCT125NS the correct choice for mixed-logic systems with TTL sources.
Does SN74AHCT125NS support operation at 3.3 V supply?
No, SN74AHCT125NS is specified only for 4.5 V to 5.5 V operation per its recommended conditions table. Attempting 3.3 V operation violates the minimum VCC requirement and risks unreliable input recognition (VIH spec assumes ≥4.5 V) and reduced output drive strength. For 3.3 V systems, consider the 74LVC125 or 74ALVC125 families instead.
What is the maximum capacitive load SN74AHCT125NS can drive while maintaining timing specs?
SN74AHCT125NS is characterized up to 50 pF load capacitance, with propagation delay (tpd) specified at 3.0–7.0 ns (max) and enable/disable times at 3.4–11.0 ns (max) under those conditions. Driving >50 pF will increase delays nonlinearly and may violate setup/hold windows in high-speed interfaces; external series termination or buffer staging is recommended for heavier loads.
Can SN74AHCT125NS inputs tolerate voltages above VCC, and what is the limit?
Yes, SN74AHCT125NS inputs tolerate voltages up to 7.0 V regardless of VCC level, as defined in its Absolute Maximum Ratings table. This overvoltage capability supports safe hot-plug operation and transient margin during power sequencing, but sustained operation above VCC requires current limiting to avoid exceeding IIK (−20 mA) clamping current limits.
Is SN74AHCT125NS pin-compatible with older 74LS125 devices?
SN74AHCT125NS is functionally and pin-compatible with 74LS125 in SO-14 packages, sharing identical pinout (1OE–14VCC), 3-state behavior, and TTL-level input compatibility. However, SN74AHCT125NS draws significantly lower ICC (≤40 µA vs. ~20 mA for LS), reduces heat generation, and supports wider temperature range (−40 °C to +125 °C vs. 0 °C to +70 °C), making it a direct, energy-efficient upgrade.
SN74AHCT125NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 14-SOIC (0.209", 5.30mm Width)
- 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 ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
SN74AHCT125NS FAQ
1.How can I place an order for SN74AHCT125NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT125NS 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 SN74AHCT125NS reliable?
The price and inventory of SN74AHCT125NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT125NS is usually 5 days.
3.What payment methods are accepted for SN74AHCT125NS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT125NS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT125NS?
SN74AHCT125NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT125NS 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 SN74AHCT125NS?
For technical support, including SN74AHCT125NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT125NS requirements.
6.How does Aetrix verify that SN74AHCT125NS is sourced from the original manufacturer or authorized distributors?
All SN74AHCT125NS 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 SN74AHCT125NS meets industry standards.
7.What is the process for return or replacement of SN74AHCT125NS?
All SN74AHCT125NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT125NS, 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 SN74AHCT125NS part is unused and in its original packaging.
Return procedure for SN74AHCT125NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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