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Texas Instruments SN74AHCT125PWRE4
- Part No.:
- SN74AHCT125PWRE4
- Manufacturer:
- Texas Instruments
- Package:
- 14-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74AHCT125PWRE4.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,246
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Product details
Overview
SN74AHCT125PWRE4 from Texas Instruments is a quadruple 3-state bus buffer gate IC with independent output-enable control per channel, TTL-compatible inputs (VIH = 2 V, VIL = 0.8 V), ±8 mA output drive at 5 V, and propagation delay ≤6.5 ns (CL = 15 pF). It enables digital signal routing, isolation, and level translation in microcontroller I/O expansion and data bus conditioning applications.
For engineers reviewing the SN74AHCT125PWRE4 datasheet, SN74AHCT125PWRE4 pinout, SN74AHCT125PWRE4 application, or SN74AHCT125PWRE4 equivalent, key selection criteria include 3-state output timing (tPZH/tPLZ ≤ 8 ns), input voltage compatibility with legacy TTL logic, thermal resistance (θJA = 147.7 °C/W for PW package), and commercial-grade operating range (–40°C to +85°C).
Technical Context
The SN74AHCT125PWRE4 implements four independent CMOS buffer gates, each with dedicated active-low output-enable (OE) control. Each gate passes A→Y when OE is low and presents high-impedance (Z) when OE is high - enabling bidirectional bus arbitration and signal gating without contention.
It operates strictly within 4.5 V to 5.5 V supply range, features TTL-voltage-compatible inputs (2 V VIH min, 0.8 V VIL max), and delivers rail-to-rail output swing with VOH ≥ 3.8 V and VOL ≤ 0.44 V under full load (±8 mA), ensuring robust noise margins in mixed-logic systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - defines valid operating window; outside this range risks functional failure or damage |
| Input Compatibility | TTL-level (VIH ≥ 2 V, VIL ≤ 0.8 V) - allows direct interface with legacy 5 V TTL outputs without level shifters |
| Output Drive | ±8 mA at VCC = 4.5 V - supports driving standard 50 Ω transmission lines or multiple CMOS inputs (fan-out ≥ 10) |
| Propagation Delay | tPLH/tPHL ≤ 6.5 ns (CL = 15 pF) - ensures sub-10 ns signal path timing for 50 MHz+ synchronous bus operation |
| 3-State Enable/Disable | tPZH/tPLZ ≤ 8 ns (CL = 15 pF) - guarantees fast bus release to prevent contention during multiplexing or hot-swap scenarios |
| Power Consumption | ICC ≤ 20 µA (static), Cpd = 14 pF - enables low-quiescent-power operation in battery-backed or always-on logic interfaces |
| Operating Temperature | –40°C to +85°C - qualified for industrial ambient environments including motor control and instrumentation enclosures |
Pinout & Package
PW package: TSSOP-14 (4.4 mm × 5.0 mm, 0.65 mm pitch), thermally enhanced with exposed pad (not electrically connected), RoHS-compliant, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 (OE) | Active-low output enable | Individually disables corresponding buffer output to high-impedance state; tie to VCC via pull-up for power-up safety |
| 2, 5, 9, 12 (A) | Buffer input | Accepts TTL-compatible digital signals; must be terminated to VCC or GND if unused to prevent floating inputs |
| 3, 6, 8, 11 (Y) | 3-state buffer output | Drives logic-high or logic-low when OE = L; enters high-Z when OE = H - enables bus sharing and signal isolation |
| 7 (GND) | Ground reference | Primary return path for all I/O and supply currents; requires low-inductance connection to system ground plane |
| 14 (VCC) | Power supply | 5 V nominal supply; requires local 0.1 µF ceramic bypass capacitor placed adjacent to pin for noise suppression |
Key Features
| Feature | Design Value |
|---|---|
| Independent 3-state control per channel | Enables selective routing of up to four data lines using separate OE pins - eliminates need for discrete gating logic |
| TTL-input compatibility | Accepts standard 5 V TTL output levels directly, avoiding external level translators in mixed-technology systems |
| High noise immunity | Guaranteed 0.4 V noise margin (VIL = 0.8 V, VIH = 2.0 V) ensures reliable operation in electrically noisy industrial environments |
| Low static current | ICC ≤ 20 µA at 5.5 V - reduces standby power in always-on control subsystems such as PLC I/O modules |
| Robust latch-up immunity | Exceeds 250 mA per JESD17 - prevents destructive latch-up during transient overvoltage or ESD events |
Applications
| Microcontroller GPIO Expansion | Industrial Bus Isolation |
|---|---|
Use Scenario: Expanding limited MCU GPIO count to drive multiple peripherals (e.g., sensors, displays, actuators) without contention. IC Role / Device Role / Timing Role: SN74AHCT125PWRE4 acts as a programmable signal router: MCU GPIOs control OE pins to selectively enable buffers, passing A→Y only for active channels. Use Value: Enables dynamic reconfiguration of I/O mapping in firmware, reducing PCB layer count versus fixed wiring or multiplexer ICs. | Use Scenario: Isolating legacy 5 V parallel bus segments (e.g., printer port, sensor array) from MCU during reset or fault conditions. IC Role / Device Role / Timing Role: SN74AHCT125PWRE4 provides controlled bus disconnection: OE tied to reset signal forces all Y outputs into high-Z, breaking electrical continuity. Use Value: Prevents back-driving damaged or unpowered downstream devices, protecting both MCU and peripheral ICs during brownout or hot-plug events. |
| LED Indicator Control | Switch Debounce Interface |
Use Scenario: Driving multiple status LEDs from a shared MCU port while maintaining independent on/off control. IC Role / Device Role / Timing Role: SN74AHCT125PWRE4 serves as current-amplifying buffer: MCU drives A inputs; OE pins modulate LED current paths via Y outputs. Use Value: Delivers 8 mA per LED (exceeding typical MCU GPIO limits), eliminating external transistors and reducing BOM cost. | Use Scenario: Conditioning mechanical switch inputs (e.g., pushbuttons, limit switches) before feeding to MCU interrupt pins. IC Role / Device Role / Timing Role: SN74AHCT125PWRE4 filters bounce by enabling/disabling buffer output synchronously with software sampling windows via OE. Use Value: Reduces firmware debounce overhead and eliminates need for RC filters or dedicated debounce ICs in space-constrained designs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT125DR | SOIC-14 package (θJA = 124.5 °C/W); same electrical specs and pinout | Higher thermal resistance limits use in high-density, convection-cooled PCBs | Select when board layout requires through-hole or larger footprint for manual assembly or thermal mass |
| SN74LVC125APWR | Lower VCC range (1.65–3.6 V); 24 mA drive; LVTTL-compatible inputs (VIH = 2 V @ VCC = 3.3 V) | Not TTL-compatible at 5 V; unsuitable for legacy 5 V systems without level shifting | Choose for modern 3.3 V systems requiring higher drive strength and lower power, not for 5 V TTL interoperability |
Compared with SN74AHCT125DR and SN74LVC125APWR, the SN74AHCT125PWRE4 uniquely balances 5 V TTL compatibility, compact TSSOP-14 footprint, and industrial temperature rating - making it optimal for retrofitting legacy equipment or space-constrained industrial controllers.
Availability
SN74AHCT125PWRE4 is available at Aetrix Electronics and suitable for industrial automation, test equipment, and embedded control systems requiring stable component supply across extended product lifecycles.
Supply support for SN74AHCT125PWRE4 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 delivering analog and embedded processing solutions, with over 90 years of innovation in logic, power, and signal chain technologies.
The SN74AHCT125PWRE4 belongs to TI's classic AHCT logic family, designed specifically for seamless integration between legacy TTL systems and modern CMOS-based controllers - emphasizing voltage compatibility, noise immunity, and reliability in industrial environments.
FAQ
What is the maximum capacitive load the SN74AHCT125PWRE4 can drive while meeting datasheet timing specifications?
The SN74AHCT125PWRE4 is characterized for CL ≤ 15 pF in switching specifications (tPLH/tPHL ≤ 6.5 ns), but supports up to 50 pF loads with guaranteed timing (tPLH/tPHL ≤ 8.5 ns). Exceeding 50 pF increases propagation delay nonlinearly and may degrade noise margins; TI recommends limiting total load capacitance to 50 pF for reliable operation per datasheet Section 8.2.1.1. The SN74AHCT125PWRE4 output stage remains stable under these conditions without external compensation.
Can the SN74AHCT125PWRE4 operate reliably at 3.3 V supply voltage?
No - the SN74AHCT125PWRE4 requires VCC between 4.5 V and 5.5 V per Recommended Operating Conditions (Section 5.2). At 3.3 V, it fails to meet VIH/VIL thresholds, exhibits excessive ICC, and violates absolute maximum ratings for input voltage relative to VCC. For 3.3 V systems, TI recommends SN74LVC125A or SN74LV125A instead. The SN74AHCT125PWRE4 is strictly a 5 V TTL-compatible device.
How should unused inputs be handled on the SN74AHCT125PWRE4?
All unused inputs (A or OE) on the SN74AHCT125PWRE4 must be terminated to either VCC or GND - never left floating - to prevent undefined logic states, increased ICC, and potential oscillation. TI recommends 10 kΩ pull-up or pull-down resistors for unused OE pins to ensure default high-impedance output; unused A inputs may be tied directly to VCC or GND. This requirement is specified in Section 5.2 and Application Note SCBA004.
Does the SN74AHCT125PWRE4 support hot-swap or live-insertion applications?
The SN74AHCT125PWRE4 is not rated for hot-swap operation. Its absolute maximum ratings do not cover powered insertion, and the absence of Ioff (power-off protection) means back-current flow can occur if VCC is absent while inputs are driven. For hot-swap interfaces, TI recommends SN74CBT125 or SN74AVC125 with explicit Ioff and power-sequence tolerance. The SN74AHCT125PWRE4 requires power to be stable before applying input signals.
What is the thermal performance of the SN74AHCT125PWRE4 in its TSSOP-14 (PW) package?
The SN74AHCT125PWRE4 in PW package has θJA = 147.7 °C/W (JEDEC Std 51-2, 2S2P board), meaning junction temperature rises ~148°C per watt of dissipated power above ambient. With typical ICC < 20 µA and switching power < 1 mW at 1 MHz, self-heating is negligible (< 0.15°C) in most applications. However, simultaneous full-load operation of all four buffers at 8 mA each increases power dissipation significantly - thermal design must account for worst-case IOL/IOH current paths.
SN74AHCT125PWRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 14-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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-TSSOP
SN74AHCT125PWRE4 FAQ
1.How can I place an order for SN74AHCT125PWRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT125PWRE4 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 SN74AHCT125PWRE4 reliable?
The price and inventory of SN74AHCT125PWRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT125PWRE4 is usually 5 days.
3.What payment methods are accepted for SN74AHCT125PWRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT125PWRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT125PWRE4?
SN74AHCT125PWRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT125PWRE4 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 SN74AHCT125PWRE4?
For technical support, including SN74AHCT125PWRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT125PWRE4 requirements.
6.How does Aetrix verify that SN74AHCT125PWRE4 is sourced from the original manufacturer or authorized distributors?
All SN74AHCT125PWRE4 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 SN74AHCT125PWRE4 meets industry standards.
7.What is the process for return or replacement of SN74AHCT125PWRE4?
All SN74AHCT125PWRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT125PWRE4, 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 SN74AHCT125PWRE4 part is unused and in its original packaging.
Return procedure for SN74AHCT125PWRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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