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onsemi MC74AC125D
- Part No.:
- MC74AC125D
- Manufacturer:
- onsemi
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MC74AC125D.pdf
- Description:
- IC BUFF NON-INVERT 6V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,728
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Product details
Overview
MC74AC125D from onsemi is a quad 3-state buffer with low-enable control, designed for bidirectional data bus isolation and signal routing in CMOS logic systems. It operates from 2.0 V to 6.0 V, delivers ±24 mA output drive, supports propagation delays as low as 1.0 ns (typical at 5.0 V), and features high-impedance outputs when disabled - enabling clean bus sharing in microcontroller peripheral interfaces.
For engineers reviewing the MC74AC125D datasheet, pinout, applications, or equivalent options, key selection criteria include supply voltage range (2.0–6.0 V), 3-state enable polarity (active-low), output drive strength (±24 mA), propagation delay (≤7.5 ns max at 5 V), and SOIC-14 package compatibility with legacy 74AC logic footprints.
Technical Context
The MC74AC125D implements four independent non-inverting buffers, each with separate active-low 3-state enable (Bn input) controlling output On. Its silicon-gate CMOS process ensures low static power consumption (ICC ≤ 80 µA) and high noise immunity (VIH = 2.1 V min at VCC = 3.0 V).
It is not TTL-compatible - unlike the pin-compatible MC74ACT125 - and requires CMOS-level input thresholds. Input leakage is limited to ±1.0 µA, and dynamic output current capability reaches ±75 mA for short-duration pulses, supporting transient load driving in mixed-signal interface staging.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.0 V to 6.0 V - supports direct interfacing with 3.3 V and 5 V logic domains without level shifters |
| Output Drive Strength | ±24 mA - sufficient to drive standard CMOS loads and moderate capacitive buses (≤50 pF) |
| Propagation Delay | ≤7.5 ns at VCC = 5.0 V, CL = 50 pF - enables reliable operation in sub-100 MHz digital control paths |
| 3-State Enable Polarity | Active-low (Bn) - simplifies connection to open-drain or active-low system control signals |
| Input Thresholds | VIH = 2.1 V (min at 3.0 V), VIL = 0.9 V (max at 3.0 V) - ensures robust noise margin in CMOS environments |
| Quiescent ICC | ≤80 µA at VCC = 5.5 V - minimizes standby power in battery-backed or low-power embedded systems |
| ESD Rating | >2000 V HBM - provides baseline handling robustness for assembly and board-level integration |
Pinout & Package
MC74AC125D is supplied in a 14-lead SOIC package (Case 751A), with 1.27 mm pitch, 8.75 mm × 3.90 mm body, and Pb-free finish. Pin 1 is index-marked; pin 7 is GND, pin 14 is VCC.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | An (Data Input) | Primary non-inverting data input for each of four buffer channels |
| 2, 5, 11, 14 | Bn (Enable Input) | Active-low 3-state enable - drives output On to high-impedance when HIGH |
| 3, 6, 12, 9 | On (Output) | Non-inverting buffered output - reflects An when Bn = LOW; high-Z when Bn = HIGH |
| 7 | GND | Ground reference for all inputs, outputs, and internal circuitry |
| 14 | VCC | Positive supply rail - must be decoupled locally per best-practice CMOS layout |
Key Features
| Feature | Design Value |
|---|---|
| Quad independent 3-state buffers | Enables simultaneous control of four isolated data paths - ideal for address/data bus gating |
| CMOS input compatibility | Accepts full-rail input voltages (0–VCC) with guaranteed switching thresholds - no external pull-ups needed |
| Low enable logic | Matches common system control architectures using active-low chip select or direction signals |
| Pb-free SOIC-14 package | Meets RoHS Directive 2011/65/EU and supports standard reflow soldering profiles (MSL Level 1) |
| High noise immunity | Input hysteresis not specified, but VIH/VIL margins exceed 30% of VCC across operating range |
Applications
| Microcontroller Bus Isolation | FPGA I/O Expansion |
|---|---|
Use Scenario: Isolating shared address/data lines between an MCU and multiple peripherals (e.g., EEPROM, ADC, display driver) to prevent contention during read/write cycles. IC Role / Device Role / Timing Role: Bidirectional 3-state buffer providing controlled signal pass-through with precise enable timing coordination. Use Value: Eliminates need for discrete MOSFET switches or complex bus arbitration logic while maintaining signal integrity up to 50 MHz. | Use Scenario: Extending FPGA GPIO count by buffering and level-translating I/O signals to external sensors or actuators operating at 3.3 V or 5 V. IC Role / Device Role / Timing Role: Signal repeater and voltage-domain translator with minimal propagation delay skew across channels. Use Value: Enables deterministic timing alignment across four parallel I/O lanes without added clock domain crossing logic. |
| Digital Test Equipment Interface | Industrial PLC Backplane Staging |
Use Scenario: Driving test probes or fixture relays from a logic controller where output must be disabled between measurements to avoid loading DUT pins. IC Role / Device Role / Timing Role: Controlled-output driver with fast disable time (tPLZ ≤ 9.5 ns) ensuring clean signal release before next test step. Use Value: Reduces measurement uncertainty caused by residual bus coupling or leakage during high-impedance hold states. | Use Scenario: Interfacing modular I/O cards to a central backplane bus in programmable logic controllers, requiring hot-swap-safe signal isolation. IC Role / Device Role / Timing Role: Fault-isolated buffer stage that prevents card insertion/removal transients from propagating to main controller. Use Value: Supports safe live insertion via controlled 3-state entry/exit - no bus glitches observed during module replacement. |
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 |
|---|---|---|---|
| MC74AC125DR2G | Same die, tape-and-reel packaging (2500 pcs), identical electrical specs and SOIC-14 footprint | No functional difference - optimized for automated SMT assembly rather than manual prototyping | Select when volume production or pick-and-place compatibility is required |
| SN74AC125N | Texas Instruments variant; same AC logic family, identical pinout, but VIH/VIL thresholds differ slightly (VIH = 2.0 V min at 3.0 V vs. 2.1 V for MC74AC125D) | Valid for drop-in use in most designs, though marginally lower noise immunity at 3.3 V | Choose if TI supply chain preference or dual-sourcing strategy applies |
Compared with MC74AC125DR2G, the MC74AC125D offers identical performance in rail-packaged form for evaluation and low-volume builds; versus SN74AC125N, it provides tighter input threshold guarantees at 3.0 V supply, improving noise margin in noisy industrial environments.
Availability
MC74AC125D is available at Aetrix Electronics and suitable for microcontroller bus isolation, FPGA I/O expansion, digital test equipment interface, and industrial PLC backplane staging requiring stable component supply and long-term manufacturability.
Supply support for MC74AC125D 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
onsemi (formerly ON Semiconductor) is a global semiconductor supplier specializing in energy-efficient power management, analog, logic, and sensor solutions for automotive, industrial, and cloud infrastructure markets.
The MC74AC125D belongs to onsemi's legacy 74AC high-speed CMOS logic family, engineered for low-power, high-noise-immunity digital interfacing in industrial control and embedded systems where reliability across temperature extremes (−40°C to +85°C) is critical.
FAQ
What is the maximum operating supply voltage for MC74AC125D?
The MC74AC125D supports a DC supply voltage range from −0.5 V to +6.5 V, with recommended operation between 2.0 V and 6.0 V. Absolute maximum rating is 6.5 V - exceeding this may cause permanent damage. For sustained reliability in industrial applications, operation at 5.0 V or 3.3 V is typical, and the device maintains full functionality and timing specifications across that range. The MC74AC125D is not rated for 7 V or higher supply rails.
Does MC74AC125D support TTL-level input signals?
No, the MC74AC125D does not support TTL-level inputs. Its input thresholds are CMOS-compatible: VIH ≥ 2.1 V at VCC = 3.0 V and ≥ 3.15 V at VCC = 4.5 V. In contrast, TTL logic requires VIH ≥ 2.0 V regardless of supply - a condition met only marginally at lower VCC. For true TTL compatibility, the pin-compatible MC74ACT125 should be used instead. The MC74AC125D is intended for pure CMOS system integration.
What is the function of the Bn pins on MC74AC125D?
The Bn pins (pins 2, 5, 11, and 14) serve as active-low 3-state enable inputs for each of the four buffer channels. When Bn = LOW, the corresponding output On follows the An input; when Bn = HIGH, On enters high-impedance state. This allows independent control of bus access per channel. Pin 14 is both B3 and VCC - a dual-function terminal confirmed in the datasheet pinout diagram and function table. The MC74AC125D does not invert the enable signal.
Can MC74AC125D be used in place of MC74HC125?
MC74AC125D and MC74HC125 are not direct substitutes due to differing speed, drive strength, and voltage thresholds. The MC74AC125D offers faster propagation (≤7.5 ns vs. ≤19 ns for HC), higher output drive (±24 mA vs. ±7.8 mA), and wider VCC range (2.0–6.0 V vs. 2.0–6.0 V, but HC has stricter VIH/VIL). While pinout matches, timing-critical or low-drive designs using MC74HC125 may experience overshoot or timing violations if replaced with MC74AC125D without layout review. The MC74AC125D is not a drop-in HC replacement.
Is MC74AC125D RoHS compliant and lead-free?
Yes, the MC74AC125D is RoHS-compliant and Pb-free, as confirmed by the "G" suffix in its ordering part numbers (e.g., MC74AC125DG, MC74AC125DTR2G) and explicit marking diagrams in the datasheet. It meets JEDEC J-STD-020 moisture sensitivity Level 1 and supports standard lead-free reflow profiles (peak temperature ≤ 260°C). The SOIC-14 package uses matte tin terminations, and no lead or cadmium is present above RoHS threshold limits. The MC74AC125D is suitable for environmentally regulated production.
MC74AC125D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74AC
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
MC74AC125D FAQ
1.How can I place an order for MC74AC125D through Aetrix?
Please submit a Request for Quotation (RFQ) for MC74AC125D 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 MC74AC125D reliable?
The price and inventory of MC74AC125D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MC74AC125D is usually 5 days.
3.What payment methods are accepted for MC74AC125D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MC74AC125D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MC74AC125D?
MC74AC125D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MC74AC125D 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 MC74AC125D?
For technical support, including MC74AC125D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MC74AC125D requirements.
6.How does Aetrix verify that MC74AC125D is sourced from the original manufacturer or authorized distributors?
All MC74AC125D 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 MC74AC125D meets industry standards.
7.What is the process for return or replacement of MC74AC125D?
All MC74AC125D units undergo pre-shipment inspection (PSI). If there is an issue with MC74AC125D, 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 MC74AC125D part is unused and in its original packaging.
Return procedure for MC74AC125D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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