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Texas Instruments SN74AHC125NSR
- Part No.:
- SN74AHC125NSR
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74AHC125NSR.pdf
- Description:
- IC BUFFER NON-INVERT 5.5V 14SOP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
SN74AHC125NSR from Texas Instruments is a quadruple bus buffer gate with independent 3-state outputs, designed for bidirectional data isolation and signal routing in digital systems. It operates across 2 V to 5.5 V, supports –40°C to 125°C industrial temperature range, delivers ±8 mA output drive at 5 V, and features four dedicated OE pins enabling per-channel enable/disable control - used in PLC I/O modules, PoE power management interfaces, and motor control logic staging.
For engineers reviewing the SN74AHC125NSR datasheet, SN74AHC125NSR pinout, SN74AHC125NSR application, or SN74AHC125NSR equivalent, key selection criteria include its 14-pin SOP (NS) package, individual output-enable architecture, 3.3 V/5 V logic compatibility, high-impedance state control during power sequencing, and latch-up immunity exceeding 250 mA per JESD17.
Technical Context
The SN74AHC125NSR implements four independent CMOS buffer gates, each with active-low output enable (OE) controlling high-impedance or pass-through behavior. Its logic function follows positive-logic truth table: when OE = L, Y = A; when OE = H, Y = Z (high-Z). No internal bus contention or feedback paths exist between channels.
It uses advanced AHC (Advanced High-Speed CMOS) process technology, delivering propagation delays as low as 1 ns (tPLH/tPHL at 5 V, CL = 50 pF), input transition rate tolerance up to 100 ns/V at 3.3 V, and guaranteed noise immunity with VIH/VIL margins defined across full VCC range (2–5.5 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 5.5 V - enables direct interfacing with 3.3 V microcontrollers and 5 V legacy peripherals without level shifters. |
| Output Drive Strength | ±8 mA at VCC = 5 V - sufficient to drive standard TTL loads and multiple CMOS inputs without external buffering. |
| Propagation Delay | 1 ns min / 6.5 ns max (A→Y, VCC = 5 V, CL = 15 pF) - supports high-speed data routing in real-time control loops. |
| 3-State Enable/Disable Time | tPZL/tPLZ ≤ 11.5 ns (VCC = 3.3 V, CL = 50 pF) - ensures clean bus arbitration with minimal glitch window during channel switching. |
| Input Leakage Current | ±1 µA max (TA = –40°C to 125°C) - guarantees stable OE and A-input biasing in unbuffered or high-impedance source configurations. |
| ESD Rating | ±1500 V HBM - meets industrial IEC 61000-4-2 system-level robustness requirements for field-deployable equipment. |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive subsystems, industrial motor drives, and PoE-powered edge devices. |
Pinout & Package
SN74AHC125NSR is housed in a 14-pin SOP (Small Outline Package) with 10.30 mm × 5.30 mm body size, gull-wing leads, and surface-mount compatibility. Pin numbering follows standard SOIC top-view convention.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | OE1–OE4 (active-low) | Independent enable controls per buffer; must be pulled high via resistor during power-up to ensure default high-Z state. |
| 2, 5, 9, 12 | A1–A4 (inputs) | Non-inverting data inputs; accept 0–5.5 V signals regardless of VCC, but logic thresholds scale with supply voltage. |
| 3, 6, 8, 11 | Y1–Y4 (outputs) | 3-state buffered outputs; sink/source up to ±8 mA; high-Z state prevents back-driving or bus contention. |
| 7 | GND | Ground reference for all logic and output stages; requires low-inductance connection to PCB ground plane. |
| 14 | VCC | Power supply input; bypassed with 0.1 µF ceramic capacitor placed within 3 mm of pin for noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Four independent 3-state buffers | Enables selective routing of four separate data lines - e.g., isolating sensor ADC outputs from shared MCU bus while maintaining timing integrity. |
| Wide VCC operating range (2–5.5 V) | Eliminates need for separate voltage translators when interfacing mixed-voltage subsystems such as 3.3 V FPGA and 5 V analog front-end. |
| Latch-up immunity >250 mA | Guarantees survivability during transient overcurrent events in motor drive gate driver interfaces or hot-swap PoE circuits. |
| Low input capacitance (10 pF max) | Minimizes loading on high-impedance sources like crystal oscillator outputs or precision DAC references. |
| Controlled output transition rates | Input rise/fall rate limit of 100 ns/V at 3.3 V suppresses crosstalk and EMI in dense PCB layouts with adjacent high-speed traces. |
Applications
| PLC Digital I/O Expansion | Power-over-Ethernet Interface |
|---|---|
|
Use Scenario: Adding isolated digital input/output capability to compact programmable logic controllers using limited GPIO resources. IC Role / Device Role / Timing Role: Acts as a configurable signal gate between field-side sensors/actuators and controller's internal bus, enabling software-selectable channel enable/disable. Use Value: Reduces PCB footprint versus discrete buffer solutions while supporting 125°C ambient operation in enclosed industrial enclosures. |
Use Scenario: Managing data and power handshaking between PoE PD controller and Ethernet PHY in IEEE 802.3af/at-compliant devices. IC Role / Device Role / Timing Role: Buffers classification signature pulses and link-layer status signals with precise timing control and voltage-level translation. Use Value: Ensures reliable detection of PSE classification current signatures by maintaining <1 ns jitter margin on pulse edges at 5 V operation. |
| Motor Control Logic Staging | Flow Meter Signal Conditioning |
|
Use Scenario: Isolating PWM command signals from microcontroller to gate drivers in BLDC motor inverters subject to high dv/dt noise. IC Role / Device Role / Timing Role: Provides noise-immune signal path with controlled edge rates and high-impedance disable state during fault shutdown. Use Value: Prevents false triggering of half-bridge drivers during overcurrent lockout by guaranteeing sub-10 ns disable-to-high-Z transition. |
Use Scenario: Routing pulse outputs from turbine or ultrasonic flow sensors to multiple metering processors in utility-grade smart meters. IC Role / Device Role / Timing Role: Splits and buffers low-duty-cycle flow pulses while preserving edge fidelity and minimizing propagation skew across channels. Use Value: Enables simultaneous timestamping across dual measurement paths with <2 ns inter-channel skew at 3.3 V supply. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC125APWR | Lower VCC range (1.65–5.5 V); higher speed (tPD = 3.2 ns @ 3.3 V); lower drive (±24 mA @ 3.3 V) | Better suited for battery-powered 1.8 V/3.3 V systems; less robust at 5 V due to absolute max rating of 5.5 V vs. AHC's 7 V | Select when optimizing for ultra-low static current (<1 µA) and 1.8 V compatibility; avoid if 5 V legacy interface or latch-up margin is critical. |
| 74AHC125D,118 (Nexperia) | Identical AHC logic family; same pinout and DC specs; slightly higher tPD (max 7.5 ns @ 5 V, CL = 50 pF) | Qualified to AEC-Q100 Grade 1 (–40°C to +125°C); preferred for automotive body electronics where qualification traceability is required | Choose for automotive production programs requiring PPAP documentation; otherwise functionally interchangeable with SN74AHC125NSR in industrial designs. |
Compared with SN74LVC125APWR and 74AHC125D,118, the SN74AHC125NSR offers superior latch-up immunity (250 mA vs. 200 mA), wider absolute max input voltage (7 V), and tighter thermal resistance (RθJA = 89.9°C/W in NS package), making it optimal for high-reliability industrial control and PoE infrastructure where robustness outweighs marginal speed gains.
Availability
SN74AHC125NSR is available at Aetrix Electronics and suitable for PLC digital I/O expansion, Power-over-Ethernet interface design, and motor control logic staging requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for SN74AHC125NSR 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 technologies, with decades of experience in industrial-grade logic and interface solutions.
The SN74AHC125NSR belongs to TI's AHC logic family, engineered for high-speed, low-power, and robust operation in harsh environments - targeting industrial automation, energy infrastructure, and real-time control systems.
FAQ
What is the recommended pull-up resistor value for OE pins on the SN74AHC125NSR during power-up?
The SN74AHC125NSR OE pins must be tied to VCC through a pull-up resistor to ensure high-impedance state at power-on. Minimum value is determined by the driver's current-sinking capability: for typical 5 V operation with 20 µA leakage, a 100 kΩ resistor suffices. TI recommends 10 kΩ for robust noise immunity in noisy industrial environments. The SN74AHC125NSR datasheet specifies no minimum OE drive strength, so resistor choice balances speed and power.
Can the SN74AHC125NSR safely interface between a 3.3 V microcontroller and a 5 V peripheral?
Yes - the SN74AHC125NSR supports VCC = 3.3 V while accepting input voltages up to 5.5 V on A and OE pins, making it ideal for level-shifting. When VCC = 3.3 V, VOH ≈ 3.15 V (min) and VOL ≈ 0.44 V (max) at 4 mA load, compatible with 5 V TTL inputs. However, outputs cannot drive 5 V logic high directly; use VCC = 5 V if driving 5 V loads. The SN74AHC125NSR's wide input voltage range eliminates external translators in mixed-voltage systems.
Does the SN74AHC125NSR require external bypass capacitors, and where should they be placed?
Yes - each VCC pin of the SN74AHC125NSR requires a 0.1 µF ceramic bypass capacitor placed within 3 mm of the pin and connected to a low-inductance ground plane. This suppresses supply noise generated during output transitions and prevents false triggering in adjacent logic. For multi-VCC designs (not applicable to SN74AHC125NSR's single VCC), smaller 0.01–0.022 µF caps per pin are recommended. The SN74AHC125NSR's fast switching (sub-10 ns edges) makes proper decoupling essential for signal integrity.
How does the SN74AHC125NSR handle unused inputs, and what is the risk of leaving them floating?
Unused inputs on the SN74AHC125NSR - including A and OE pins - must never be left floating, as undefined voltages cause increased ICC, logic instability, or oscillation. TI mandates tying unused OE pins to VCC (for default high-Z) or GND (for always-enabled), and unused A inputs to VCC or GND depending on desired default state. Floating inputs on the SN74AHC125NSR can draw excessive current and induce electromagnetic interference in adjacent traces, violating IEC 61000-4-2 immunity targets.
What is the maximum capacitive load the SN74AHC125NSR can drive while maintaining specified timing?
The SN74AHC125NSR is characterized for CL = 15 pF and CL = 50 pF loads. At VCC = 5 V, tPLH/tPHL increases from 3.8 ns (min) to 5.3 ns (min) as CL rises from 15 pF to 50 pF. Driving >50 pF degrades timing predictability and may exceed output current limits (±8 mA). For loads >50 pF, add series termination or use a buffer with higher drive strength. The SN74AHC125NSR's 10 pF input capacitance ensures minimal loading on upstream drivers, preserving signal rise time.
SN74AHC125NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 14-SOIC (0.209", 5.30mm 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:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
SN74AHC125NSR FAQ
1.How can I place an order for SN74AHC125NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC125NSR 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 SN74AHC125NSR reliable?
The price and inventory of SN74AHC125NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC125NSR is usually 5 days.
3.What payment methods are accepted for SN74AHC125NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC125NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHC125NSR?
SN74AHC125NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC125NSR 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 SN74AHC125NSR?
For technical support, including SN74AHC125NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC125NSR requirements.
6.How does Aetrix verify that SN74AHC125NSR is sourced from the original manufacturer or authorized distributors?
All SN74AHC125NSR 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 SN74AHC125NSR meets industry standards.
7.What is the process for return or replacement of SN74AHC125NSR?
All SN74AHC125NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC125NSR, 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 SN74AHC125NSR part is unused and in its original packaging.
Return procedure for SN74AHC125NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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