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Texas Instruments SN74AHC125DR
- Part No.:
- SN74AHC125DR
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AHC125DR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,130
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Product details
Overview
SN74AHC125DR 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 expansion and PoE controller interface logic.
For engineers reviewing the SN74AHC125DR datasheet, SN74AHC125DR pinout, SN74AHC125DR application, or SN74AHC125DR equivalent, this page provides verified functional specifications, SOIC-14 package details, real-world use cases in motor control and point-of-sale systems, and validated alternative parts with documented electrical and application-level differences.
Technical Context
The SN74AHC125DR 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-hold or Schmitt-triggering is present - inputs respond directly to applied voltage levels.
It uses advanced AHC (Advanced High-Speed CMOS) process technology, delivering rail-to-rail output swing, low propagation delay (as low as 3.8 ns at 5 V/15 pF), and robust noise immunity (VIL(D) = 1.5 V, VIH(D) = 3.5 V at 5 V). Power supply rejection is maintained across full VCC range without external regulation.
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 families without level shifters. |
| Output Drive Strength | ±8 mA at VCC = 5 V - sufficient to drive standard TTL loads and multiple CMOS inputs without fanout limitation. |
| Propagation Delay | 3.8 ns (max, A→Y, VCC = 5 V, CL = 15 pF) - supports >100 MHz data rates in short-bus applications. |
| Input Thresholds | VIH = 3.85 V, VIL = 1.65 V at VCC = 5.5 V - ensures reliable recognition of 3.3 V logic HIGH when powered at 5.5 V. |
| Operating Temperature | –40°C to +125°C - qualified for under-hood automotive, industrial motor drives, and PoE-powered equipment. |
| ESD Rating | ±1500 V HBM - meets IEC 61000-4-2 Level 2 for system-level ESD robustness in field-deployed controllers. |
| Quiescent Current | 40 µA max (TA = –40°C to 125°C) - supports low-power standby modes in battery-backed PLC modules. |
Pinout & Package
SN74AHC125DR is supplied in a 14-pin SOIC (D) package measuring 8.65 mm × 3.91 mm, with standard 1.27 mm pitch, gull-wing leads, and RoHS-compliant NiPdAu finish. Thermal resistance RθJA = 124.5°C/W enables operation up to 125°C ambient with minimal heatsinking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 (OE1–OE4) | Active-low output enable | Individually disables corresponding buffer output to high-Z; must be pulled to VCC via resistor during power-up to prevent bus contention. |
| 2, 5, 9, 12 (A1–A4) | Buffer input | CMOS-compatible digital input accepting 0–VCC logic levels; no internal pull-up/down. |
| 3, 6, 8, 11 (Y1–Y4) | Buffer output | 3-state CMOS output capable of sourcing/sinking ±8 mA; high-Z state isolates downstream bus segments. |
| 7 (GND) | Ground reference | Primary return path for all I/O and supply currents; requires low-inductance connection to PCB ground plane. |
| 14 (VCC) | Power supply | Single-supply rail supporting 2–5.5 V; requires local 0.1 µF ceramic bypass capacitor placed within 3 mm. |
Key Features
| Feature | Design Value |
|---|---|
| Independent 3-state control per channel | Four separate OE pins allow selective isolation of individual data lines - critical for dynamic bus arbitration in multi-master systems. |
| Rail-to-rail output swing | VOH ≥ 4.4 V and VOL ≤ 0.5 V at VCC = 5 V ensures full logic margin when driving legacy TTL or mixed-voltage interfaces. |
| Wide VCC operating range | 2 V to 5.5 V operation permits use in both 3.3 V microcontroller domains and 5 V legacy backplanes without voltage translation. |
| Low input capacitance | Ci = 10 pF max - minimizes loading on high-speed clock or data sources, preserving signal integrity in dense PCB layouts. |
| Latch-up immunity | Exceeds 250 mA per JESD17 - prevents destructive latch-up during transient overvoltage events in industrial I/O modules. |
Applications
| Programmable Logic Controllers | Power Over Ethernet (PoE) |
|---|---|
Use Scenario: Isolating sensor input buses and actuator output buses in modular PLC backplanes where multiple I/O cards share a common data highway. IC Role / Device Role / Timing Role: Bus buffer providing direction-controlled signal gating between CPU bus and peripheral slots, with per-slot OE control enabling hot-swap capability. Use Value: Prevents bus contention during card insertion/removal and allows firmware-selectable I/O mapping without hardware reconfiguration. |
Use Scenario: Level-shifting and isolating data lines between the PoE controller IC (typically 3.3 V) and legacy 5 V PHY or management MCU. IC Role / Device Role / Timing Role: Bidirectional buffer enabling shared MDIO/MDC or SMBus lines between PoE PSE and PD subsystems operating at different supply voltages. Use Value: Eliminates need for discrete level translators while maintaining timing-critical setup/hold margins due to sub-10 ns propagation delay. |
| Motor Drives and Controls | Electronic Point-of-Sale |
Use Scenario: Routing encoder feedback signals and PWM command signals between motion controller and servo driver modules in compact industrial drives. IC Role / Device Role / Timing Role: Signal conditioner buffering quadrature encoder A/B/Z channels to reduce capacitive loading and improve noise immunity on long cable runs. Use Value: Maintains clean edge transitions at >1 MHz encoder rates while suppressing ground bounce-induced glitches in noisy motor environments. |
Use Scenario: Managing parallel data paths between thermal printer head drivers, cash drawer solenoid controls, and barcode scanner interfaces in embedded POS terminals. IC Role / Device Role / Timing Role: Output expander enabling single GPIO bank to control up to four independent peripherals with independent enable timing. Use Value: Reduces MCU pin count requirements and simplifies firmware by decoupling peripheral activation timing from data transfer timing. |
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 drive (±24 mA at 3.3 V); faster tPLH/tPHL (2.5 ns typ at 3.3 V). | Better suited for 1.8 V/3.3 V mixed-signal systems; not recommended for 5 V-only designs due to reduced noise margin. | Select when interfacing with modern low-voltage MCUs and requiring higher fanout or tighter timing budgets. |
| 74AHC125D,112 (Nexperia) | Identical AHC logic family; same pinout and DC specs; slightly higher RθJA (130°C/W vs 124.5°C/W). | Drop-in replacement in SOIC-14 footprint; identical functional behavior but with minor thermal derating at full load. | Choose for dual-sourcing flexibility in cost-sensitive industrial designs where TI part availability is constrained. |
Compared with SN74LVC125APWR and 74AHC125D,112, the SN74AHC125DR offers optimal balance of wide supply tolerance, proven industrial temperature reliability, and predictable timing across 2–5.5 V - making it preferred for legacy 5 V systems and mixed-voltage brownout resilience.
Availability
SN74AHC125DR is available at Aetrix Electronics and suitable for programmable logic controllers, Power over Ethernet infrastructure, and motor drive control systems requiring stable component supply across extended temperature ranges and multi-year production cycles.
Supply support for SN74AHC125DR 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 over 50 years of innovation in industrial-grade logic and interface solutions.
The SN74AHC125DR belongs to TI's AHC logic family - engineered for high-speed, low-power, and wide-voltage-operation digital interfacing in harsh industrial and automotive environments.
FAQ
What is the maximum output current rating for SN74AHC125DR?
The SN74AHC125DR supports ±8 mA per output at VCC = 5 V, as specified in the Recommended Operating Conditions table. This rating applies under continuous DC conditions and assumes proper PCB thermal design. Exceeding this limit risks output stage degradation or increased VOL/VOH deviation beyond specification limits.
Does SN74AHC125DR require external pull-up resistors on its OE pins?
Yes - to ensure high-impedance state during power-up or power-down, each OE pin of the SN74AHC125DR must be tied to VCC through an external pull-up resistor. The minimum value depends on the driver's current-sinking capability; typical values range from 10 kΩ to 100 kΩ for most microcontroller GPIO implementations.
Can SN74AHC125DR operate reliably at 2.5 V supply voltage?
Yes - the SN74AHC125DR is fully specified from 2 V to 5.5 V. At VCC = 2.5 V, VIH = 1.7 V and VIL = 0.7 V, with propagation delay increasing to ~9.5 ns (max) and output drive reducing to ±4 mA. All timing and DC parameters remain guaranteed across this range per the datasheet's Recommended Operating Conditions.
Is SN74AHC125DR pin-compatible with older 74HC125 devices?
No - although functionally similar, SN74AHC125DR uses Advanced High-Speed CMOS (AHC) technology with lower input thresholds, faster switching, and improved noise immunity compared to standard HC. Pinout matches, but VIH/VIL levels differ significantly; direct substitution may cause logic misreads without supply voltage alignment.
What is the thermal resistance (RθJA) of SN74AHC125DR in SOIC-14 package?
The SN74AHC125DR in SOIC-14 (D) package has a junction-to-ambient thermal resistance (RθJA) of 124.5°C/W, measured under JEDEC-standard 2S2P board conditions. This value assumes two copper layers, 1-inch² copper pour, and no forced airflow - actual performance improves with enhanced PCB copper area or thermal vias.
SN74AHC125DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 14-SOIC (0.154", 3.90mm 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-SOIC
SN74AHC125DR FAQ
1.How can I place an order for SN74AHC125DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC125DR 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 SN74AHC125DR reliable?
The price and inventory of SN74AHC125DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC125DR is usually 5 days.
3.What payment methods are accepted for SN74AHC125DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC125DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHC125DR?
SN74AHC125DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC125DR 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 SN74AHC125DR?
For technical support, including SN74AHC125DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC125DR requirements.
6.How does Aetrix verify that SN74AHC125DR is sourced from the original manufacturer or authorized distributors?
All SN74AHC125DR 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 SN74AHC125DR meets industry standards.
7.What is the process for return or replacement of SN74AHC125DR?
All SN74AHC125DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC125DR, 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 SN74AHC125DR part is unused and in its original packaging.
Return procedure for SN74AHC125DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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