SN74LS125ADE4 Texas Instruments Integrated Circuit (Small Outline Packages) In Stock
Texas Instruments SN74LS125ADE4 is a quad bus buffer with 3-state outputs from the LS logic family, featuring four independent 1-bit unidirectional drivers with active-low output enable controls and 24 mA output low drive in a 14-pin SOIC package. Each buffer gate tristates its output when the enable input is high, allowing multiple devices to share a common data bus without contention. This device is widely used in microprocessor address and data buses, memory interface circuits, and general-purpose digital bus buffering in industrial, consumer, and legacy embedded systems.
- Manufacturer
- Texas Instruments
- Package
- Small Outline Packages
- Pin Count
- 14
- Lifecycle
- OBSOLETE
- Datasheet
- SN74LS125ADE4 Datasheet PDF
- Category
- Integrated Circuit
- Temp Range
- ?°C to 70.0°C
- RoHS
- Compliant
- Lead Time
- 3–7 business days
- Shipping
- DHL Express · Worldwide
Key Features
- 4 independent 3-state bus driver gates with active-low output enable for bus sharing
- 24 mA output low current per channel for robust TTL-compatible bus driving
- 45 pF rated load capacitance covering standard PCB bus trace lengths
- LS family 5 V TTL logic levels for compatibility with legacy digital systems
- 14-pin SOIC package with compact footprint for high-density logic boards
- Unidirectional buffer architecture simplifying bus direction control
Applications
The SN74LS125ADE4 is extensively used in microprocessor data bus buffers, address demultiplexer circuits, and memory-mapped I/O interfaces where multiple bus masters must share a common 8-bit or 16-bit bus. Legacy industrial control systems with 5 V TTL backplanes and older embedded computing platforms retain this device for bus isolation and signal drive restoration. It also serves as a fanout buffer in clock distribution trees and as a signal multiplexer output stage in test equipment.
Specifications
| YTEOL | 0 |
| Control Type | ENABLE LOW |
| Count Direction | UNIDIRECTIONAL |
| Family | LS |
| JESD-30 Code | R-PDSO-G14 |
| JESD-609 Code | e4 |
| Load Capacitance (CL) | 45pF |
| Logic IC Type | BUS DRIVER |
| Max I(ol) | 0.024A |
| Number of Bits | 1 |
| Number of Functions | 4 |
| Number of Ports | 2 |
| Output Characteristics | 3-STATE |
| Output Polarity | TRUE |
| Package Body Material | PLASTIC/EPOXY |
| Package Equivalence Code | SOP14,.25 |
| Package Shape | RECTANGULAR |
| Package Style | SMALL OUTLINE |
| Packing Method | TUBE |
| Peak Reflow Temperature (Cel) | 260 |
| Power Supply Current-Max (ICC) | 20mA |
| Prop. Delay@Nom-Sup | 18ns |
| Propagation Delay (tpd) | 18ns |
| Qualification Status | Not Qualified |
| Supply Voltage-Max (Vsup) | 5.25V |
| Supply Voltage-Min (Vsup) | 4.75V |
| Supply Voltage-Nom (Vsup) | 5V |
| Surface Mount | YES |
| Technology | TTL |
| Temperature Grade | COMMERCIAL |
| Terminal Finish | NICKEL PALLADIUM GOLD |
| Terminal Form | GULL WING |
| Terminal Pitch | 1.27mm |
| Terminal Position | DUAL |
| Time@Peak Reflow Temperature-Max (s) | 30 |
| ## SN74LS125ADE4 Alternates Showing results | Image |
| Package | Small Outline Packages |
Compliance & Regulatory
| RoHS Status | Compliant |
| Lead-Free | Yes (Pb-Free) |
| Moisture Sensitivity Level | MSL 1 |
| HTS Code | 8542.39.00.60 |
Alternate & Equivalent Parts
Compatible alternatives and drop-in replacements for SN74LS125ADE4:
Frequently Asked Questions
How many 3-state buffer gates does SN74LS125ADE4 include, and how is each gate enabled?
The SN74LS125ADE4 contains 4 independent 3-state buffer gates, each controlled by a dedicated active-low output enable pin. When the enable input is logic low, the gate drives the output with up to 24 mA of sink current; when high, the output floats to high impedance, allowing other devices to drive the shared bus line without contention.
For a legacy 5 V microprocessor bus design, why is SN74LS125ADE4 still a practical choice over newer AHC or LVC alternatives?
The SN74LS125ADE4 operates with 5 V TTL-compatible input thresholds and 5 V output swings, matching legacy microprocessors, EPROM, and peripheral chips that require true 5 V logic levels. Modern AHC or LVC devices operate at 3.3 V, which may require level shifters in a pure 5 V TTL system. The LS device's 45 pF load rating and 24 mA drive also align with the original bus specifications of many legacy backplane designs.
Can SN74LS125ADE4 drive multiple parallel loads on a shared data bus simultaneously?
Yes, with 24 mA output low current per gate, a single SN74LS125ADE4 channel can drive a bus loaded with 8 to 10 standard TTL inputs in parallel, each drawing approximately 1.6 mA to 2 mA. The 45 pF load capacitance specification ensures reliable switching at standard LS-family propagation delays of approximately 7 ns to 12 ns, making it suitable for bus-buffering up to 20 MHz clock rates.
Which package does SN74LS125ADE4 use, and how does the SOIC footprint benefit board assembly?
The SN74LS125ADE4 is housed in a 14-pin SOIC package, which is surface-mount compatible and occupies roughly 8.65 mm x 3.9 mm of PCB area. The SOIC footprint supports automated pick-and-place assembly and reflow soldering, reducing assembly labor compared to legacy DIP-14 through-hole versions while maintaining the same logical function and 5 V TTL electrical characteristics.
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About Texas Instruments
Texas Instruments (TI) is a global semiconductor company headquartered in Dallas, Texas. TI designs and manufactures analog and embedded processing chips used in industrial, automotive, consumer, communications, and enterprise systems.
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