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Texas Instruments SN74AHCT125DRG4
- Part No.:
- SN74AHCT125DRG4
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AHCT125DRG4.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,138
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Product details
Overview
SN74AHCT125DRG4 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 drive strength at 5 V, and SOIC-14 package. It enables bidirectional signal isolation in digital interface routing, such as microcontroller GPIO expansion or legacy bus buffering.
For engineers reviewing the SN74AHCT125DRG4 datasheet, SN74AHCT125DRG4 pinout, SN74AHCT125DRG4 application, or SN74AHCT125DRG4 equivalent, key selection criteria include 3-state output timing (tPLH/tPHL ≤ 6.5 ns @ 15 pF), input voltage compatibility with 5-V TTL logic families, and SOIC-14 thermal performance (θJA = 124.5°C/W).
Technical Context
The SN74AHCT125DRG4 implements four independent non-inverting buffers, each with dedicated active-low output-enable (OE) control. When OE is low, the A→Y path is enabled with propagation delay under 6.5 ns; when OE is high, Y enters high-impedance state-critical for bus contention avoidance and dynamic signal gating.
Its CMOS design with TTL-input thresholds ensures interoperability with legacy 5-V logic while maintaining low static current (ICC ≤ 20 µA) and robust noise immunity (VIL(D) = 0.8 V, VIH(D) = 2 V). Power-up high-impedance behavior requires OE tied to VCC via pullup resistor to prevent floating outputs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - defines valid operating range for guaranteed VOH ≥ 3.8 V and VOL ≤ 0.44 V |
| Output Drive | ±8 mA - supports direct connection to standard 5-V CMOS/TTL loads without external buffering |
| Propagation Delay | ≤ 6.5 ns (A→Y, CL = 15 pF) - enables use in 100+ MHz data paths with tight timing budgets |
| Input Compatibility | TTL-level (VIH = 2 V, VIL = 0.8 V) - allows direct interfacing with 74LS, 74F, and other 5-V bipolar logic families |
| 3-State Enable Time | tPZH ≤ 8 ns (OE→Y, CL = 15 pF) - ensures fast bus release for time-critical arbitration protocols |
| Power Dissipation | Cpd = 14 pF - enables accurate dynamic power estimation (P = Cpd × V² × f) for thermal design |
| Operating Temperature | –40°C to +85°C - qualified for commercial industrial environments, not automotive or extended temp |
Pinout & Package
SN74AHCT125DRG4 uses a 14-pin SOIC (D) package with 1.27 mm pitch, 8.65 mm × 3.91 mm body, and standard JEDEC MS-012AC footprint. Pin numbering follows top-view convention with Pin 1 marked by beveled corner or dot.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 (OE) | Active-low output enable | Individually disables corresponding buffer output to high-Z; must be pulled up to VCC during power-up |
| 2, 5, 9, 12 (A) | Buffer input | Non-inverting data input; accepts TTL-compatible logic levels (0.8 V/2 V thresholds) |
| 3, 6, 8, 11 (Y) | Buffer output | 3-state push-pull output; drives high/low or floats based on OE state |
| 7 (GND) | Ground reference | Return path for all I/O and supply currents; requires low-impedance PCB plane connection |
| 14 (VCC) | Power supply | 5-V nominal supply; requires local 0.1 µF bypass capacitor placed adjacent to pin |
Key Features
| Feature | Design Value |
|---|---|
| Independent 3-state control | Four separate OE pins allow selective activation of individual buffers-enables dynamic bus partitioning without external logic |
| TTL-compatible inputs | VIH = 2 V / VIL = 0.8 V thresholds ensure reliable interfacing with legacy 5-V TTL families without level-shifting circuitry |
| High-impedance power-up | OE tied to VCC via pullup forces all outputs into high-Z at power-on-prevents bus contention during system initialization |
| Low dynamic power | Cpd = 14 pF enables sub-mW operation at 10 MHz (P ≈ 0.35 mW @ 5 V), reducing thermal load in dense logic layouts |
| Latch-up immunity | Exceeds 250 mA per JESD17 - ensures robustness against transient ground bounce or supply rail collapse events |
Applications
| Microcontroller GPIO Expansion | Legacy Bus Signal Buffering |
|---|---|
Use Scenario: Expanding limited MCU GPIOs to drive multiple peripherals (e.g., sensors, displays) without contention. IC Role / Device Role / Timing Role: Acts as configurable signal gate-each buffer isolates one peripheral line; OE pins controlled by spare GPIOs. Use Value: Enables software-selectable peripheral enable/disable with nanosecond switching, eliminating need for discrete MOSFET switches or multiplexers. |
Use Scenario: Interfacing modern microcontrollers to legacy 5-V parallel buses (e.g., ISA, printer ports) requiring level-compatible drivers. IC Role / Device Role / Timing Role: Provides bidirectional 3-state buffering between mismatched logic families; OE synchronized to bus control signals (RD/WR). Use Value: Maintains signal integrity across long traces with <6.5 ns propagation delay and ±8 mA drive-avoids timing violations in 10–20 MHz bus cycles. |
| Switch Debouncing Circuit | Noise-Immune Digital Input Conditioning |
Use Scenario: Cleaning mechanical switch inputs (pushbuttons, encoders) before feeding to interrupt-capable MCU pins. IC Role / Device Role / Timing Role: Buffers switch signal while OE holds output in high-Z until contact settles; debounced output fed to MCU. Use Value: Eliminates external RC networks and firmware debounce routines-hardware-based settling using TTL input hysteresis (VIH–VIL = 1.2 V). |
Use Scenario: Conditioning slow-rising or EMI-corrupted signals from industrial sensors or long cables before digital processing. IC Role / Device Role / Timing Role: Sharpens edges and rejects sub-1.2 V noise spikes via TTL input thresholds; 3-state output prevents backfeeding into sensitive circuits. Use Value: Achieves clean logic transitions without Schmitt triggers-leverages inherent input noise margin (VIL(D)/VIH(D)) and fast output slew rate. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74AHCT125DR | Same die, identical electrical specs; differs only in RoHS compliance marking (no "G4" suffix) and tape/reel packaging variant | No functional difference; both rated for –40°C to +85°C, SOIC-14, same pinout and timing | Select SN74AHCT125DR if RoHS exemption documentation is not required; otherwise SN74AHCT125DRG4 preferred for full compliance traceability |
| SN74LVC125APWR | Lower VCC range (1.65–3.6 V), higher speed (tPD ≤ 3.7 ns), but incompatible TTL input thresholds (VIH = 2 V only at VCC = 3.3 V) | Suitable for 3.3-V systems with faster timing needs; unsuitable for direct 5-V TTL interfacing without level translation | Choose SN74LVC125APWR only in pure 3.3-V designs where speed >6.5 ns matters; avoid in mixed-voltage or legacy 5-V environments |
Compared with SN74AHCT125DR and SN74LVC125APWR, SN74AHCT125DRG4 uniquely balances 5-V TTL compatibility, SOIC-14 manufacturability, and industrial temperature support-making it the default choice for retrofitting or upgrading legacy digital interfaces without redesigning voltage domains.
Availability
SN74AHCT125DRG4 is available at Aetrix Electronics and suitable for industrial control panels, test equipment interfaces, and embedded system bus expansion requiring stable component supply and long-term obsolescence management.
Supply support for SN74AHCT125DRG4 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 logic solutions, with over 50 years of innovation in industrial, automotive, and communications markets.
The SN74AHCT125DRG4 belongs to TI's AHCT logic family-designed specifically for seamless 5-V TTL-to-CMOS bridging in cost-sensitive, noise-resilient industrial applications where reliability and pin compatibility outweigh ultra-low power or high-speed requirements.
FAQ
What is the maximum capacitive load SN74AHCT125DRG4 can drive while meeting datasheet timing specs?
The SN74AHCT125DRG4 is characterized for CL ≤ 15 pF in timing tables (tPLH/tPHL ≤ 6.5 ns), and supports up to 50 pF with relaxed delays (tPLH/tPHL ≤ 8.5 ns). Driving >50 pF risks violating setup/hold margins and increasing dynamic power; TI recommends limiting total load to 50 pF unless re-characterized for specific conditions. The SN74AHCT125DRG4 datasheet specifies this limit in Section 8.2.1.1.
Can SN74AHCT125DRG4 operate at 3.3 V supply voltage?
No-SN74AHCT125DRG4 is specified only for VCC = 4.5 V to 5.5 V per Section 5.2. At 3.3 V, VOH drops below TTL VIH minimum (2 V), causing unreliable HIGH-level recognition by downstream TTL devices. For 3.3-V systems, use SN74LVC125APWR instead. The SN74AHCT125DRG4 absolute maximum rating allows 3.3 V temporarily but guarantees no functionality there.
How should unused inputs be terminated on SN74AHCT125DRG4?
All unused inputs (A or OE) on SN74AHCT125DRG4 must be tied to VCC or GND-never left floating-to prevent oscillation, excess current draw, and ESD vulnerability. TI recommends 10-kΩ pullup/pulldown resistors for flexibility; direct connection is acceptable if state is fixed. This requirement is documented in Section 5.2 and Application Note SCBA004 cited in the SN74AHCT125DRG4 datasheet.
Is SN74AHCT125DRG4 pin-compatible with SN74AHCT125DR?
Yes-SN74AHCT125DRG4 and SN74AHCT125DR share identical SOIC-14 package dimensions, pinout, electrical specifications, and thermal characteristics. The "G4" suffix denotes RoHS-compliant lead finish (NIPDAU) and updated tape-and-reel packaging; no PCB layout changes are needed when substituting SN74AHCT125DRG4 for SN74AHCT125DR in existing designs.
Does SN74AHCT125DRG4 support hot-swap or live-insertion?
No-SN74AHCT125DRG4 lacks hot-swap protection features like power-up 3-state or Ioff. During partial power application, undefined OE states may cause bus contention or excessive ICC. TI explicitly advises tying OE to VCC via pullup for power-up high-Z behavior, but full hot-swap capability requires dedicated hot-swap controllers. This limitation is noted in Section 7.4 and Figure 4-1 of the SN74AHCT125DRG4 datasheet.
SN74AHCT125DRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- Package/Case:
- 14-SOIC (0.154", 3.90mm 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-SOIC
SN74AHCT125DRG4 FAQ
1.How can I place an order for SN74AHCT125DRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT125DRG4 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 SN74AHCT125DRG4 reliable?
The price and inventory of SN74AHCT125DRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT125DRG4 is usually 5 days.
3.What payment methods are accepted for SN74AHCT125DRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT125DRG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT125DRG4?
SN74AHCT125DRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT125DRG4 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 SN74AHCT125DRG4?
For technical support, including SN74AHCT125DRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT125DRG4 requirements.
6.How does Aetrix verify that SN74AHCT125DRG4 is sourced from the original manufacturer or authorized distributors?
All SN74AHCT125DRG4 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 SN74AHCT125DRG4 meets industry standards.
7.What is the process for return or replacement of SN74AHCT125DRG4?
All SN74AHCT125DRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT125DRG4, 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 SN74AHCT125DRG4 part is unused and in its original packaging.
Return procedure for SN74AHCT125DRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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