My Inquiry
My Account
Texas Instruments SN74AHC125N
- Part No.:
- SN74AHC125N
- Manufacturer:
- Texas Instruments
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74AHC125N.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,294
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74AHC125N from Texas Instruments is a quadruple bus buffer gate with independent 3-state outputs, designed for logic-level translation and bidirectional bus isolation in industrial control and embedded systems. It operates from 2 V to 5.5 V, supports –40°C to 125°C ambient temperature, delivers ±8 mA output drive at 5 V, and features four dedicated OE pins enabling per-channel enable/disable control. It is commonly used in PLC I/O modules to isolate microcontroller GPIOs from field-side sensor/actuator buses.
For engineers reviewing the SN74AHC125N datasheet, SN74AHC125N pinout, SN74AHC125N application, or SN74AHC125N equivalent, this page provides verified functional specifications, validated PDIP-14 package details, confirmed 3-state timing behavior (tPLH/tPHL ≤ 6.5 ns at 5 V), and real-world implementation guidance for bus buffering in PoE-powered edge nodes and motor drive interface circuits.
Technical Context
The SN74AHC125N implements four independent CMOS buffer gates, each with a dedicated active-low output-enable (OE) input controlling high-impedance or pass-through operation. Its A→Y signal path exhibits rail-to-rail voltage transfer with guaranteed VOH ≥ 4.4 V and VOL ≤ 0.5 V under 8 mA load at VCC = 4.5 V.
Each channel operates independently: when OE is low, the Y output replicates the A input; when OE is high, Y enters high-impedance state. Power-up robustness requires OE tied to VCC via pullup resistor to ensure defined 3-state during supply ramp.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 5.5 V - enables direct interfacing with 3.3 V and 5 V logic domains without level shifters |
| Output Drive Strength | ±8 mA at VCC = 4.5 V - sufficient to drive standard TTL loads and moderate PCB trace capacitance |
| Propagation Delay | ≤ 6.5 ns (A→Y, CL = 15 pF, VCC = 5 V) - supports >100 MHz bus toggle rates in short-path configurations |
| 3-State Enable/Disable Time | tPZL/tPLZ ≤ 8 ns (OE→Y, CL = 15 pF, VCC = 5 V) - ensures clean bus arbitration with minimal contention window |
| Input Thresholds | VIH = 3.85 V, VIL = 1.65 V at VCC = 5.5 V - compatible with 5 V CMOS logic families and rejects noise up to 1.65 V |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive, industrial motor drives, and PoE-powered equipment |
| ESD Rating | HBM ±1500 V - meets IEC 61000-4-2 Level 2 for system-level ESD immunity in end equipment |
Pinout & Package
SN74AHC125N uses a 14-pin plastic dual in-line package (PDIP) with 19.30 mm × 6.35 mm body size and through-hole mounting. Pin spacing is 2.54 mm (0.1 inch), compatible with standard 0.6-inch DIP sockets and wave-solder processes.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | OE1–OE4 | Active-low output enable inputs - each controls one buffer independently; must be pulled high for power-up safety |
| 2, 5, 9, 12 | A1–A4 | Buffer input terminals - accept CMOS-compatible logic levels referenced to VCC |
| 3, 6, 8, 11 | Y1–Y4 | 3-state output terminals - drive high, low, or high-Z based on corresponding OE state |
| 7 | GND | Ground reference - all internal logic and output stages referenced to this node |
| 14 | VCC | Positive supply - powers all four buffers; requires local 0.1 µF bypass capacitor |
Key Features
| Feature | Design Value |
|---|---|
| Independent Output Enables | Four separate OE pins allow selective activation of individual buffers - critical for dynamic bus segmentation in multi-sensor PLC backplanes |
| Rail-to-Rail Output Swing | VOH ≥ 4.4 V and VOL ≤ 0.5 V at full load - eliminates need for external pullups/pulldowns in 5 V systems |
| Wide Supply Range | 2 V to 5.5 V operation - supports mixed-voltage designs and brownout resilience down to 2 V |
| High-Noise Immunity | VIH/VIL thresholds scale with VCC - maintains consistent noise margin across supply voltages |
| Low Quiescent Current | ICC ≤ 40 µA over full temperature range - suitable for always-on monitoring circuits in energy-sensitive PoE endpoints |
Applications
| Programmable Logic Controllers | Power Over Ethernet Devices |
|---|---|
Use Scenario: Isolating microcontroller GPIOs from field-side analog/digital I/O modules in modular PLC racks. IC Role / Device Role / Timing Role: Bus buffer providing direction-controlled signal routing between CPU bus and isolated I/O expansion cards. Use Value: Prevents back-driving during hot-swap events and enables software-selectable channel mapping via individual OE control. | Use Scenario: Managing data and control lines between PoE-powered MCU and powered device (PD) interface circuitry. IC Role / Device Role / Timing Role: Level-shifting and bus-isolation buffer ensuring safe communication during PoE negotiation and power classification phases. Use Value: Enables simultaneous use of same MCU pins for both legacy 5 V peripherals and IEEE 802.3af/at signaling without contention. |
| Motor Drive Control Boards | Electronic Point-of-Sale Terminals |
Use Scenario: Interfacing MCU PWM outputs and feedback signals (encoder, current sense) to high-noise motor power stages. IC Role / Device Role / Timing Role: Unidirectional buffer isolating sensitive logic from ground bounce and switching transients on motor driver PCBs. Use Value: Reduces false triggering of fault detection logic by suppressing coupled noise on feedback paths during IGBT switching. | Use Scenario: Multiplexing multiple peripheral interfaces (barcode scanner, receipt printer, cash drawer) onto limited MCU GPIO resources. IC Role / Device Role / Timing Role: Digital MUX substitute using OE pins to route signals from shared data bus to selected peripheral. Use Value: Eliminates need for discrete analog switches or additional MCU pins while maintaining deterministic signal timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT125N | TTL-compatible input thresholds (VIH = 2 V min at VCC = 4.5 V); otherwise identical pinout and function | Better suited for interfacing with legacy 5 V TTL logic where AHC's higher VIH would cause marginal recognition | Select SN74AHCT125N when connecting to older 74LS or 74F series devices; retain SN74AHC125N for pure CMOS systems |
| 74LVC125N | Lower VCC range (1.65 V–5.5 V); higher speed (tPD ≤ 4.2 ns at 3.3 V); different input thresholds | Preferred for 1.8 V/2.5 V mixed-signal systems and high-speed digital interfaces requiring sub-5 ns propagation | Choose 74LVC125N only if operating below 2 V or requiring faster timing; SN74AHC125N remains optimal for 3.3 V/5 V industrial environments |
Compared with SN74AHCT125N and 74LVC125N, the SN74AHC125N offers superior noise immunity at 5 V due to its CMOS-input threshold scaling, wider supply margin for brownout tolerance, and proven thermal performance in PDIP packaging for convection-cooled industrial enclosures.
Availability
SN74AHC125N is available at Aetrix Electronics and suitable for programmable logic controllers, Power over Ethernet (PoE) infrastructure, and motor drive control systems requiring stable component supply, long-term obsolescence management, and RoHS-compliant through-hole assembly.
Supply support for SN74AHC125N 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 for industrial, automotive, and communications markets.
The SN74AHC125N belongs to TI's industry-standard 74AHC logic family, engineered for robust, low-power bus buffering in harsh environments where reliability, wide temperature operation, and predictable 3-state behavior are critical.
FAQ
What is the maximum recommended operating voltage for SN74AHC125N?
The absolute maximum supply voltage for SN74AHC125N is 7 V, but the recommended operating range is 2 V to 5.5 V per TI's SCLS256O datasheet. Operating continuously above 5.5 V risks parametric degradation and violates the device's qualified specification limits. For reliable long-term operation in industrial applications, maintain VCC within 5.5 V, with 5.0 V ±5% being the most common design point for compatibility with legacy 5 V systems.
Does SN74AHC125N support hot-swap or live-insertion scenarios?
SN74AHC125N does not include built-in hot-swap protection circuitry, but its 3-state outputs and high-impedance disable mode make it suitable for controlled hot-swap implementations when OE pins are managed externally. To ensure safe insertion, tie all OE pins to VCC via pullup resistors and sequence VCC before applying input signals. The device's ±1500 V HBM ESD rating also supports handling during board replacement in field-serviceable equipment containing SN74AHC125N.
Can SN74AHC125N be used for bidirectional data flow?
No, SN74AHC125N is strictly unidirectional: each channel passes data from A input to Y output only. It cannot transmit in reverse (Y→A). For true bidirectional bus transceivers, TI recommends alternatives like SN74LVC245A. However, two SN74AHC125N devices can be paired with complementary OE control to emulate bidirectional behavior on separate traces - a technique used in isolated SPI or UART signal routing where direction is software-determined and mutually exclusive.
What is the thermal resistance (RθJA) of SN74AHC125N in its PDIP package?
The junction-to-ambient thermal resistance (RθJA) for SN74AHC125N in the 14-pin PDIP package is 56.3°C/W, as specified in Section 5.4 of the TI datasheet SCLS256O. This value assumes standard JEDEC 2S2P test board conditions. In typical through-hole PCB layouts with modest copper area, actual thermal performance may improve slightly, but derating is advised above 70°C ambient to maintain junction temperature below 125°C under full 8 mA per-output load.
How should unused inputs be handled on SN74AHC125N?
All unused inputs on SN74AHC125N - including A1–A4 and OE1–OE4 - must be terminated to a valid logic level (VCC or GND) to prevent floating states that cause excessive ICC, erratic output behavior, or EMI. TI recommends tying unused OE pins to VCC (via pullup) to force associated outputs into high-Z, and unused A inputs to GND or VCC depending on desired default state. Leaving any input unconnected violates the device's functional specification and risks latch-up in noisy industrial environments.
SN74AHC125N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- 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:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
SN74AHC125N FAQ
1.How can I place an order for SN74AHC125N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC125N 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 SN74AHC125N reliable?
The price and inventory of SN74AHC125N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC125N is usually 5 days.
3.What payment methods are accepted for SN74AHC125N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC125N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHC125N?
SN74AHC125N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC125N 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 SN74AHC125N?
For technical support, including SN74AHC125N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC125N requirements.
6.How does Aetrix verify that SN74AHC125N is sourced from the original manufacturer or authorized distributors?
All SN74AHC125N 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 SN74AHC125N meets industry standards.
7.What is the process for return or replacement of SN74AHC125N?
All SN74AHC125N units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC125N, 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 SN74AHC125N part is unused and in its original packaging.
Return procedure for SN74AHC125N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74AHC125N Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
