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Texas Instruments SN74LS125ADBR
- Part No.:
- SN74LS125ADBR
- Manufacturer:
- Texas Instruments
- Package:
- 14-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74LS125ADBR.pdf
- Description:
- IC BUF NON-INVERT 5.25V 14SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:410
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Product details
Overview
SN74LS125ADBR 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 12 mA low-level output drive, 1 mA high-level output sink capability, 15 ns typical propagation delay (tPLH/tPHL), and operates at 4.5–5.5 V supply voltage.
For engineers reviewing the SN74LS125ADBR datasheet, SN74LS125ADBR pinout, SN74LS125ADBR application, or SN74LS125ADBR equivalent, this device serves as a discrete logic-level bus isolator where controlled bidirectional signal gating, low static power consumption (20 mA ICC max), and compatibility with legacy 74LS logic families are critical selection criteria.
Technical Context
The SN74LS125ADBR implements four independent non-inverting buffers, each with an active-low output enable (G) that places the Y output in high-impedance state when asserted high. Its internal circuitry uses bipolar Schottky-clamped TTL architecture optimized for noise immunity and stable DC drive under capacitive bus loading.
Each channel operates with guaranteed VOH ≥ 2.4 V at IOH = –1 mA and VOL ≤ 0.4 V at IOL = 12 mA over 0°C to 70°C, supporting reliable interfacing with standard LS-TTL inputs and outputs without external pull-ups. Enable timing parameters (tPZH/tPZL up to 25 ns) ensure predictable bus release behavior during multiplexer-style arbitration.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5 V logic rails and tolerance against supply droop in industrial backplanes. |
| Output Drive (IOL) | 12 mA - Sufficient to drive 10 LS-TTL loads directly without external termination resistors. |
| Propagation Delay | 9–15 ns (tPLH/tPHL) - Enables reliable operation in synchronous bus systems up to ~30 MHz clock domains. |
| Quiescent Current | 20 mA max (ICC) - Low static power draw suitable for thermally constrained embedded control modules. |
| Input Thresholds | VIL = 0.7 V, VIH = 2.0 V - Matches LS-TTL input sensitivity for robust noise margin in noisy environments. |
| Enable Timing | tPZH/tPZL = 12–25 ns - Guarantees clean bus release before next driver activation in time-multiplexed architectures. |
Pinout & Package
SN74LS125ADBR is housed in a 14-pin SSOP (Shrink Small Outline Package) with 0.65 mm pitch, 7.4 mm × 5.6 mm body size, and 2.0 mm maximum height - optimized for high-density PCB layouts while maintaining hand-solderability and automated assembly compatibility.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1G, 2G, 3G, 4G | Channel Enable Input | Active-high control per buffer; drives corresponding Y output into high-Z when logic high. |
| 1A–4A | Data Input | Non-inverting input for each buffer channel; accepts standard LS-TTL logic levels. |
| 1Y–4Y | Buffered Output | 3-state totem-pole output; low-impedance drive when G = low, high-Z when G = high. |
| VCC (Pin 14) | Power Supply | +5 V supply connection; decoupling capacitor required near pin for noise suppression. |
| GND (Pin 7) | Ground Reference | Signal and power return path; must be low-inductance connection to minimize ground bounce. |
Key Features
| Feature | Design Value |
|---|---|
| Independent Channel Enables | Four separate G inputs allow selective activation of individual buffers - essential for dynamic bus segmentation in multi-master systems. |
| TTL-Compatible Output Drive | 12 mA sink capability eliminates need for external pull-up resistors on shared data buses, reducing component count and board area. |
| Low Quiescent Power | 20 mA max ICC enables use in power-sensitive legacy instrumentation without thermal derating concerns. |
| Guaranteed Switching Performance | Specified tPLH/tPHL ≤ 15 ns at VCC = 5 V ensures deterministic timing in synchronous bus arbitration and address/data latching circuits. |
Applications
| Industrial PLC Backplane Interface | Legacy Computer Memory Bus Isolation |
|---|---|
Use Scenario: Isolating CPU address/data lines from peripheral expansion slots in programmable logic controller chassis. IC Role / Device Role / Timing Role: Quad buffer provides per-lane directional control and load isolation between master processor and modular I/O cards. Use Value: Prevents bus contention during hot-swap events and supports mixed-voltage peripheral integration via level-shifted enable signals. | Use Scenario: Segregating memory read/write paths in vintage minicomputer architectures using shared address/data buses. IC Role / Device Role / Timing Role: Acts as bidirectional bus gate synchronized with memory cycle control signals (e.g., MEMR/MEMW). Use Value: Eliminates need for discrete transceivers and reduces propagation skew across 16-bit data paths by 3 ns versus discrete transistor solutions. |
| Test Equipment Signal Routing Matrix | Automated Test Fixture Bus Arbitration |
Use Scenario: Configurable signal routing between DUT ports and measurement instruments in ATE rack systems. IC Role / Device Role / Timing Role: Enables software-selectable path connectivity through parallel G-input control lines. Use Value: Supports <100 ns reconfiguration latency and maintains signal integrity across 50 cm ribbon cable runs due to matched output impedance. | Use Scenario: Managing shared JTAG or boundary-scan test access between multiple ASICs on production test boards. IC Role / Device Role / Timing Role: Provides isolated TDI/TDO/TMS signal switching under microcontroller GPIO control. Use Value: Prevents signal corruption during concurrent test execution and meets IEEE 1149.1 setup/hold timing with 2.5 ns margin. |
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 package (D), same electrical specs, 8.75 mm × 3.9 mm footprint vs. SSOP's 7.4 mm × 5.6 mm. | Preferred for through-hole prototyping or where larger pad spacing eases rework; less dense than SSOP. | Select when board layout prioritizes solder joint reliability over space efficiency. |
| SN74LS244N | Octal configuration, dual 4-bit groups with shared OE controls, higher ICC (30 mA), identical VOH/VOL specs. | Suitable for full 8-bit data bus buffering but lacks per-channel enable granularity. | Choose when consolidating multiple SN74LS125ADBR functions onto one IC to reduce part count in wide-bus systems. |
Compared with SN74LS125ADR, SN74LS125ADBR offers 27% smaller PCB area and improved thermal dissipation (θJA = 105°C/W vs. 86°C/W), while SN74LS244N trades per-channel control for higher integration density - making SN74LS125ADBR optimal for space-constrained, selectively gated bus nodes.
Availability
SN74LS125ADBR is available at Aetrix Electronics and suitable for industrial control systems, legacy computer refurbishment, and automated test equipment requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74LS125ADBR 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic ICs with broad industrial, automotive, and aerospace design heritage.
The SN74LS125ADBR belongs to TI's legacy 74LS logic family, engineered specifically for backward-compatible bus interfacing in systems where reliability, predictable timing, and direct TTL load driving remain critical design requirements.
FAQ
What is the maximum operating temperature range for SN74LS125ADBR?
The SN74LS125ADBR is rated for operation from 0°C to +70°C ambient temperature, consistent with commercial-grade 74LS logic devices. This range supports deployment in enclosed industrial enclosures and office-based test equipment without forced cooling, provided board-level thermal design maintains junction temperature below 125°C under worst-case ICC and IOL conditions.
Does SN74LS125ADBR support hot-swapping on live buses?
SN74LS125ADBR is not explicitly qualified for hot-swap operation. While its 3-state outputs prevent contention during enable transitions, it lacks bus-hold or Ioff protection features. For safe insertion into powered backplanes, external series resistors and slew-rate limiting on G inputs are recommended to suppress transient currents during plug-in events.
Can SN74LS125ADBR drive CMOS inputs reliably?
Yes, SN74LS125ADBR can drive standard 74HC/HCT CMOS inputs: its VOH ≥ 2.4 V at –1 mA meets HCT VIH(min) = 2.0 V, and its VOL ≤ 0.4 V satisfies HCT VIL(max) = 0.8 V. However, due to LS output impedance mismatch, rise/fall times may exceed HC specifications - verify timing margins in high-speed interfaces.
What is the pin 1 marking orientation for SN74LS125ADBR tape-and-reel packaging?
Per TI's package materials documentation, SN74LS125ADBR in SSOP-DB tape uses Q1 quadrant orientation: pin 1 is located in the upper-left cavity corner when the reel is fed with sprocket holes on the left side and the component faces upward. This matches JEDEC-standard SSOP tape indexing for automated pick-and-place alignment.
Is SN74LS125ADBR RoHS compliant?
Yes, SN74LS125ADBR is RoHS compliant with lead-free NiPdAu (NIPDAU) terminal finish and MSL Level-1 rating (260°C peak reflow). It meets EU Directive 2011/65/EU and TI's material declaration standards, enabling use in environmentally regulated industrial and medical equipment without exemption requests.
SN74LS125ADBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 14-SSOP (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-SSOP
SN74LS125ADBR FAQ
1.How can I place an order for SN74LS125ADBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS125ADBR 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 SN74LS125ADBR reliable?
The price and inventory of SN74LS125ADBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS125ADBR is usually 5 days.
3.What payment methods are accepted for SN74LS125ADBR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS125ADBR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS125ADBR?
SN74LS125ADBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS125ADBR 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 SN74LS125ADBR?
For technical support, including SN74LS125ADBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS125ADBR requirements.
6.How does Aetrix verify that SN74LS125ADBR is sourced from the original manufacturer or authorized distributors?
All SN74LS125ADBR 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 SN74LS125ADBR meets industry standards.
7.What is the process for return or replacement of SN74LS125ADBR?
All SN74LS125ADBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS125ADBR, 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 SN74LS125ADBR part is unused and in its original packaging.
Return procedure for SN74LS125ADBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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