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Texas Instruments SN74LS125ANSR
- Part No.:
- SN74LS125ANSR
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74LS125ANSR.pdf
- Description:
- IC BUF NON-INVERT 5.25V 14SOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,981
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Product details
Overview
SN74LS125ANSR from Texas Instruments is a quad 3-state bus buffer with independent channel enable control, designed for TTL-compatible data bus isolation and driving in industrial control and legacy computing systems. It features low-impedance active outputs (IOH = –1 mA, IOL = 12 mA), high-impedance disabled state, and operates at VCC = 4.5–5.5 V across 0°C to 70°C.
For engineers reviewing the SN74LS125ANSR datasheet, SN74LS125ANSR pinout, SN74LS125ANSR application, or SN74LS125ANSR equivalent, this page delivers verified electrical specs, SOP-14 package details, real-world use cases in bus arbitration and level translation, and validated alternative options for legacy system maintenance.
Technical Context
The SN74LS125ANSR implements four independent non-inverting buffers, each with an active-low output enable (G) that disables the output to high-impedance when logic high. Its LS-TTL circuitry uses bipolar transistor design optimized for reduced power consumption versus standard TTL while maintaining compatible voltage thresholds (VIH = 2 V, VIL = 0.7 V).
Propagation delay is specified at tPLH/tPHL ≤ 15 ns (VCC = 5 V, RL = 667 Ω, CL = 45 pF), and output enable/disable timing (tPZH/tPZL ≤ 25 ns) supports reliable bus sharing in synchronous digital systems without external pull-ups.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V TTL logic rails and stable operation under typical supply variation. |
| IOH / IOL | –1 mA / 12 mA - Sufficient drive strength to sink 12 mA or source 1 mA while maintaining VOH ≥ 2.4 V and VOL ≤ 0.4 V. |
| VIH / VIL | 2.0 V / 0.7 V - Matches TTL input thresholds, enabling direct interfacing with legacy 74LS/74S families without level shifters. |
| tPLH / tPHL | ≤ 15 ns - Supports bus speeds up to ~33 MHz in point-to-point configurations with 45 pF load. |
| ICC (max) | 20 mA - Low quiescent current per device enables dense board layouts without excessive power rail loading. |
| θJA (NS) | 76 °C/W - Thermal performance suitable for ambient temperatures up to 70°C in standard PCB layouts with moderate copper area. |
Pinout & Package
SOP-14 (NS) package: 14-pin small-outline plastic package with gull-wing leads, 0.65 mm pitch, 8.1 mm × 10.4 mm body size, RoHS-compliant NiPdAu lead finish, MSL Level-1 rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1G, 2G, 3G, 4G | Channel enable inputs (active-high) | Each controls one buffer independently; high = output enabled (Y = A), low = high-Z state. |
| 1A–4A | Data inputs | Non-inverting input signals routed to corresponding outputs when respective G is high. |
| 1Y–4Y | 3-state buffered outputs | Drive bus lines directly; present high impedance when associated G is low - no external pull-up required. |
| 7 | GND | Ground reference for all internal circuitry and output stages. |
| 14 | VCC | Positive supply terminal; must be decoupled locally to suppress switching noise on shared 5 V rail. |
Key Features
| Feature | Design Value |
|---|---|
| Independent 3-state control per channel | Enables selective bus segment isolation without affecting other channels - critical for multi-master arbitration. |
| TTL-compatible input/output levels | Direct drop-in replacement for 74LS125A in existing designs; no interface logic or resistor networks needed. |
| No external pull-up resistors required | Outputs actively drive high and low states; high-Z mode eliminates bus contention and simplifies PCB routing. |
| Low ICC (20 mA max) | Reduces total system power draw in multi-buffer configurations - advantageous for fanless industrial enclosures. |
Applications
| Industrial Bus Arbitration | Legacy Computer Backplane Interface |
|---|---|
Use Scenario: Isolating multiple microcontroller peripherals sharing a common data bus in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: SN74LS125ANSR acts as bidirectional bus buffer with per-peripheral enable control, preventing signal contention during read/write cycles. Use Value: Enables deterministic bus access using discrete enable signals - avoids need for complex bus controllers or arbitration logic. | Use Scenario: Interfacing ISA-bus expansion cards with different timing requirements in retro-computing restoration projects. IC Role / Device Role / Timing Role: SN74LS125ANSR provides level-consistent buffering between CPU address/data lines and card-specific logic, preserving signal integrity over long traces. Use Value: Maintains TTL-compatible VIH/VOL margins across temperature, ensuring reliable boot and I/O operations in aging hardware. |
| Test Equipment Signal Routing | Embedded System Debug Interface |
Use Scenario: Multiplexing test signals from multiple DUTs onto a single acquisition channel in automated test fixtures. IC Role / Device Role / Timing Role: SN74LS125ANSR serves as gated signal selector - only one channel enabled at a time to prevent bus loading and crosstalk. Use Value: Eliminates mechanical relays or analog switches; reduces fixture complexity and improves long-term reliability. | Use Scenario: Isolating JTAG/SWD debug pins between host debugger and target MCU during firmware development. IC Role / Device Role / Timing Role: SN74LS125ANSR buffers TCK/TMS/TDI signals with controlled enable, preventing backdrive during target reset or power-down. Use Value: Protects debugger ICs from latch-up or damage due to target-side voltage transients or floating states. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS125ADR | SOIC-14 (D) package; identical electrical specs and pinout; θJA = 86 °C/W vs. 76 °C/W for NS. | Preferred where board space allows larger SOIC footprint and thermal margin is less constrained. | Select SN74LS125ADR if existing layout uses SOIC pads or reflow profile favors D-package thermal mass. |
| SN74LS125AN | PDIP-14 (N) package; same logic function and DC specs; higher θJA = 80 °C/W; through-hole mounting. | Suitable for prototyping, repair of legacy through-hole boards, or environments requiring mechanical robustness. | Choose SN74LS125AN for hand-soldered repairs, breadboard evaluation, or vibration-prone industrial housings. |
Compared with SN74LS125ADR and SN74LS125AN, the SN74LS125ANSR offers the smallest PCB footprint (SOP-14), best thermal resistance (76 °C/W), and tape-and-reel compatibility for automated SMT assembly - making it optimal for volume production of space-constrained industrial modules.
Availability
SN74LS125ANSR is available at Aetrix Electronics and suitable for industrial bus arbitration, legacy computer backplane interfaces, and embedded debug isolation requiring stable component supply across extended product lifecycles.
Supply support for SN74LS125ANSR 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 90 years of innovation in industrial, automotive, and communications markets.
The SN74LS125ANSR belongs to TI's legacy 74LS logic family, engineered specifically for reliable, low-power bus interfacing in industrial control, instrumentation, and retro-computing applications where TTL compatibility and long-term part availability are essential.
FAQ
What is the operating temperature range for SN74LS125ANSR?
The SN74LS125ANSR is rated for operation from 0°C to 70°C, matching commercial-grade specifications for industrial and embedded applications. This range is confirmed in the "Recommended Operating Conditions" table of the SDLS044A datasheet, and aligns with its SOP-14 (NS) packaging qualification. The device is not rated for extended temperature ranges such as –40°C to 85°C or military grades.
Does SN74LS125ANSR require external pull-up resistors on its outputs?
No, SN74LS125ANSR does not require external pull-up resistors. Its 3-state outputs actively drive both high and low logic levels when enabled, and present true high-impedance (Hi-Z) when disabled - eliminating bus contention and removing the need for pull-up components. This behavior is explicitly documented in the functional description and schematics of the SDLS044A datasheet.
Is SN74LS125ANSR pin-compatible with SN74LS125ADR or SN74LS125AN?
Yes, SN74LS125ANSR is pin-compatible with SN74LS125ADR (SOIC-14) and SN74LS125AN (PDIP-14): all three share identical pin numbering, signal assignments (1G–4G, 1A–4A, 1Y–4Y, GND, VCC), and logic functionality. Mechanical differences exist only in package type and dimensions - no PCB redesign is needed when substituting between these variants.
What is the maximum output current capability of SN74LS125ANSR?
The SN74LS125ANSR supports a maximum low-level output current (IOL) of 12 mA and high-level output current (IOH) of –1 mA under recommended operating conditions (VCC = 4.5–5.5 V, TA = 0°C to 70°C). These values ensure robust TTL-level drive into standard bus loads while maintaining VOH ≥ 2.4 V and VOL ≤ 0.4 V, as verified in the "Electrical Characteristics" section of SDLS044A.
Can SN74LS125ANSR be used in place of SN74LS126A?
No, SN74LS125ANSR is not functionally interchangeable with SN74LS126A. While both are quad 3-state buffers, SN74LS125ANSR has active-high enable (G high = output enabled), whereas SN74LS126A uses active-low enable (G low = output enabled). Swapping them without inverting the enable signal will invert buffer behavior and cause bus contention or failure.
SN74LS125ANSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 14-SOIC (0.209", 5.30mm 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:
- 2.6mA, 24mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
SN74LS125ANSR FAQ
1.How can I place an order for SN74LS125ANSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS125ANSR 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 SN74LS125ANSR reliable?
The price and inventory of SN74LS125ANSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS125ANSR is usually 5 days.
3.What payment methods are accepted for SN74LS125ANSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS125ANSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS125ANSR?
SN74LS125ANSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS125ANSR 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 SN74LS125ANSR?
For technical support, including SN74LS125ANSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS125ANSR requirements.
6.How does Aetrix verify that SN74LS125ANSR is sourced from the original manufacturer or authorized distributors?
All SN74LS125ANSR 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 SN74LS125ANSR meets industry standards.
7.What is the process for return or replacement of SN74LS125ANSR?
All SN74LS125ANSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS125ANSR, 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 SN74LS125ANSR part is unused and in its original packaging.
Return procedure for SN74LS125ANSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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