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onsemi 74F125SCX
- Part No.:
- 74F125SCX
- Manufacturer:
- onsemi
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
74F125SCX.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,638
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Product details
Overview
74F125SCX from Fairchild Semiconductor is a quad 3-state buffer IC used for bus driving and signal isolation in TTL-compatible digital systems. It features four independent non-inverting buffers, each with active-high enable, 4.5–5.5 V supply operation, propagation delays as low as 2.0 ns (tPLH), and ±12 mA output drive capability. It is commonly deployed in address/data bus buffering in industrial control logic.
For engineers reviewing the 74F125SCX datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed 3-state leakage (±50 µA), fan-out of 600/106.6 (standard/3-state), output short-circuit current rating (−225 mA), and JEDEC MS-120 SOIC-14 narrow-body packaging.
Technical Context
The 74F125SCX implements four identical non-inverting buffer gates, each with an independent active-high 3-state enable input (Bn). Its TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) ensure interoperability with standard 5 V logic families. Output stages support high-current sinking (IOL = 64 mA) and sourcing (IOH = −12 mA) under defined load conditions.
AC performance is characterized at CL = 50 pF and VCC = 5.0 V, with tPLH/tPHL ≤ 6.5 ns over 0°C to +70°C, and 3-state timing parameters (tPZH, tPHZ) specified down to 1.5 ns. Power supply current varies by output state: ICCH = 24.0 mA (HIGH), ICCL = 40.0 mA (LOW), ICCZ = 35.0 mA (HIGH-Z).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | +4.5 V to +5.5 V - ensures compatibility with standard 5 V TTL and CMOS systems |
| Propagation Delay (tPLH) | 2.0–6.5 ns - enables high-speed bus arbitration in 20+ MHz synchronous logic |
| Output Drive (IOL / IOH) | 64 mA / −12 mA - supports direct driving of multiple TTL loads or moderate-capacitance traces |
| 3-State Leakage (IOZL / IOZH) | ±50 µA - guarantees minimal bus contention during high-impedance state |
| Fan-Out (Standard / 3-State) | 600 / 106.6 - allows one 74F125SCX output to drive up to 106 other F-series inputs in tri-state mode |
| Input Thresholds (VIH / VIL) | 2.0 V / 0.8 V - provides noise margin >0.4 V against TTL-level interference |
| Operating Temperature | 0°C to +70°C - rated for commercial-grade embedded logic applications |
Pinout & Package
74F125SCX is housed in a 14-lead Small Outline Integrated Circuit (SOIC), JEDEC MS-120, 0.150" narrow body package (Package Number M14A). Pin pitch is 1.27 mm, body width 3.9 mm, and total length 8.65 mm.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | Buffer Input (An) | Non-inverting data input per channel; accepts TTL-compatible logic levels |
| 2, 5, 11, 14 | Enable Input (Bn) | Active-high 3-state control for corresponding output; HIGH enables, LOW disables |
| 3, 6, 12, 9 | Buffer Output (On) | Non-inverting buffered output; enters high-impedance state when Bn = LOW |
| 7 | GND | Ground reference for all logic and power terminals |
| 14 | VCC | +5 V supply rail; decoupling capacitor required near pin for noise suppression |
Key Features
| Feature | Design Value |
|---|---|
| High-impedance inputs | Input loading limited to 1.0 unit load (UL), reducing capacitive burden on upstream drivers |
| Guaranteed 3-state isolation | Output leakage ±50 µA ensures negligible current flow during disabled state, critical for shared bus integrity |
| TTL-compatible thresholds | VIH ≥ 2.0 V and VIL ≤ 0.8 V meet standard TTL interface requirements without level-shifting |
| Low propagation skew | tPLH/tPHL matching ≤ 1.5 ns across channels minimizes timing uncertainty in parallel bus paths |
| Robust short-circuit tolerance | IOS = −225 mA rating allows safe momentary output contention without latch-up or damage |
Applications
| Microprocessor Address Bus Buffering | Industrial PLC I/O Expansion Module |
|---|---|
Use Scenario: Isolating and driving multiplexed address lines between CPU and memory-mapped peripherals in a 16-bit industrial controller. IC Role / Device Role / Timing Role: Quad non-inverting buffer with per-channel 3-state control, enabling dynamic bus sharing between CPU, DMA, and FPGA logic. Use Value: 64 mA sink capability drives 100+ pF trace capacitance; 2.0 ns tPLH ensures setup time compliance at 25 MHz clock rates. | Use Scenario: Level-shifting and bus isolation between legacy 5 V TTL backplane and modular I/O cards in programmable logic controllers. IC Role / Device Role / Timing Role: Signal repeater and contention guard for shared data bus; enables hot-swap-safe peripheral insertion via controlled 3-state enable sequencing. Use Value: ±50 µA 3-state leakage prevents false reads during card insertion; 0.8 V VIL ensures reliable detection of noisy field sensor signals. |
| Test Equipment Digital Pattern Generator | Legacy Computer System Backplane Interface |
Use Scenario: Driving synchronized stimulus waveforms to DUT pins in automated test equipment requiring precise edge alignment. IC Role / Device Role / Timing Role: Low-skew buffer stage delivering matched delay paths for parallel 8-bit pattern outputs. Use Value: tPLH/tPHL variation ≤ 1.5 ns across channels maintains <1 ns inter-channel skew, critical for setup/hold timing margins. | Use Scenario: Interfacing ISA-bus-compatible expansion cards with motherboard logic in retro-computing restoration projects. IC Role / Device Role / Timing Role: Bidirectional bus driver with isolated enable control, supporting both memory-mapped and I/O-mapped transactions. Use Value: Fan-out of 106.6 in 3-state mode allows single 74F125SCX to service up to four ISA slots without additional buffering. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad 3-state buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F125N | PDIP-14 package (N14A); identical AC/DC specs; slightly higher ICCZ (35.0 mA vs. 27.6 mA typ) | No surface-mount capability; suited for prototyping or through-hole legacy systems | Select when board assembly uses wave soldering or breadboard evaluation is required |
| MC74F125N | Same logic function and pinout; manufactured by ON Semiconductor post-Fairchild acquisition; identical parametric specs per datasheet rev. 2003 | No functional difference; long-term supply continuity supported via ON Semi's active product line | Preferred for new designs requiring extended lifecycle assurance and dual-source availability |
Compared with SN74F125N and MC74F125N, the 74F125SCX offers superior thermal performance and board-space efficiency in SOIC-14 packaging, while maintaining full electrical equivalence-making it optimal for high-density commercial PCB layouts where reflow assembly and thermal management are prioritized.
Availability
74F125SCX is available at Aetrix Electronics and suitable for microprocessor bus buffering, industrial PLC I/O expansion, automated test equipment pattern generation, and legacy computer backplane interfacing requiring stable component supply and long-term obsolescence mitigation.
Supply support for 74F125SCX 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
Fairchild Semiconductor was a U.S.-based semiconductor company specializing in analog and mixed-signal ICs, power management, and logic devices before its acquisition by ON Semiconductor in 2016.
The 74F125SCX belongs to the Fairchild F-Series TTL logic family, engineered for high-speed, low-power 5 V digital system interfacing with strict timing predictability and robust bus-driving capability.
FAQ
What is the maximum operating temperature range for the 74F125SCX?
The 74F125SCX is rated for commercial operation from 0°C to +70°C ambient temperature. This range is explicitly defined in the Absolute Maximum Ratings and Recommended Operating Conditions sections of the Fairchild DS009475 datasheet. Junction temperature must not exceed +150°C under bias. The 74F125SCX does not support extended industrial (−40°C to +85°C) or automotive temperature grades.
Does the 74F125SCX support true bidirectional data flow?
No, the 74F125SCX is a unidirectional non-inverting buffer with active-high 3-state enable. Each channel has dedicated input (An), enable (Bn), and output (On) terminals; there is no internal direction control or bus transceiver functionality. For bidirectional operation, discrete directional control logic or a dedicated transceiver like the 74F245 must be used alongside the 74F125SCX.
What is the recommended decoupling capacitor value for the 74F125SCX VCC pin?
A 0.1 µF ceramic capacitor placed as close as possible to the VCC (pin 14) and GND (pin 7) terminals is recommended for the 74F125SCX. This value is consistent with Fairchild's F-Series design guidelines and mitigates high-frequency switching noise generated during output transitions, especially critical given its 2 ns propagation delay and 64 mA output drive capability.
Is the 74F125SCX pin-compatible with the 74LS125?
Yes, the 74F125SCX is pin-compatible with the 74LS125 in SOIC-14 (M14A) packaging, sharing identical pin assignments and logic function. However, the 74F125SCX delivers faster propagation delays (≤6.5 ns vs. ≤15 ns), higher output drive (64 mA vs. 8 mA), and greater power supply current (ICCL up to 40 mA vs. 22 mA), requiring careful PCB thermal and power delivery review during drop-in replacement.
What does the "X" suffix in 74F125SCX signify?
Per Fairchild's ordering code convention in DS009475, the "X" suffix in 74F125SCX indicates tape-and-reel packaging-specifically, 2500 units per reel in JEDEC-standard SOIC-14 carrier tape. The base part 74F125SC denotes the same device in tube packaging. Electrical, thermal, and functional specifications are identical between 74F125SC and 74F125SCX.
74F125SCX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74F
- 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:
- 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
74F125SCX FAQ
1.How can I place an order for 74F125SCX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74F125SCX 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 74F125SCX reliable?
The price and inventory of 74F125SCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74F125SCX is usually 5 days.
3.What payment methods are accepted for 74F125SCX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74F125SCX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74F125SCX?
74F125SCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74F125SCX 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 74F125SCX?
For technical support, including 74F125SCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74F125SCX requirements.
6.How does Aetrix verify that 74F125SCX is sourced from the original manufacturer or authorized distributors?
All 74F125SCX 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 74F125SCX meets industry standards.
7.What is the process for return or replacement of 74F125SCX?
All 74F125SCX units undergo pre-shipment inspection (PSI). If there is an issue with 74F125SCX, 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 74F125SCX part is unused and in its original packaging.
Return procedure for 74F125SCX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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