My Inquiry
My Account
Texas Instruments SN74HCT125DRE4
- Part No.:
- SN74HCT125DRE4
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74HCT125DRE4.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,197
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
SN74HCT125DRE4 from Texas Instruments is a quadruple 3-state bus buffer gate IC with TTL-compatible inputs and independent enable control per channel, operating at 4.5–5.5 V, delivering ±6-mA output drive, 12-ns typical propagation delay, and 80-µA max supply current - used for bidirectional data bus isolation and memory address buffering in industrial control logic.
For engineers reviewing the SN74HCT125DRE4 datasheet, SN74HCT125DRE4 pinout, SN74HCT125DRE4 application, or SN74HCT125DRE4 equivalent, key selection criteria include 3-state timing (ten/tdis), input voltage compatibility (VIH/VIL), thermal resistance (RθJA = 138.7°C/W), and SOIC-14 package mechanical fit for legacy board layouts.
Technical Context
This device implements four independent non-inverting buffers (Y = A), each with dedicated active-low 3-state output-enable (OE) control. All inputs accept standard TTL voltage thresholds (VIH = 2 V, VIL = 0.8 V) across 4.5–5.5 V supply, enabling direct interface with legacy LSTTL logic without level shifting.
Each output supports high-current sinking and sourcing (±6 mA at 5 V) into 50-pF loads, with guaranteed switching performance: tpd ≤ 25 ns (max), ten ≤ 35 ns (max), tdis ≤ 33 ns (max) at VCC = 5.5 V and TA = 25°C - optimized for synchronous bus arbitration in microcontroller peripheral interfaces.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with 5-V TTL and CMOS systems; excludes 3.3-V operation. |
| Propagation Delay (tpd) | 10–25 ns (max at 5.5 V) - defines maximum clock-to-output latency for timing-critical bus gating. |
| Output Drive Current | ±6 mA at 5 V - sufficient to drive 15 LSTTL loads directly, eliminating need for external line drivers. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - matches standard TTL logic levels, enabling seamless interconnection with 74LS/74ALS families. |
| Quiescent Supply Current | 80 µA max - enables low-static-power operation in always-on control logic without thermal derating. |
| 3-State Enable/Disable Time | ten ≤ 35 ns, tdis ≤ 33 ns (max at 5.5 V) - critical for glitch-free bus sharing during multi-master arbitration. |
| Input Capacitance | 10 pF max - minimizes capacitive loading on upstream drivers and preserves signal edge integrity. |
Pinout & Package
SN74HCT125DRE4 uses a 14-pin SOIC (D) package with nominal body size 8.65 mm × 3.90 mm and maximum height 1.75 mm - compatible with standard SOIC-14 footprints and reflow profiles (MSL Level-1, 260°C peak).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | Output Enable (OE) | Active-low control per buffer; high = high-impedance output; tie to VCC via pullup for power-up safety. |
| 2, 5, 11, 14 | Input (A) | Non-inverting data input per channel; TTL-voltage compatible (0.8 V / 2.0 V thresholds). |
| 3, 6, 12, 9 | Output (Y) | 3-state buffered output; drives bus lines or address registers; sinks/sources ±6 mA at 5 V. |
| 7 | GND | Ground reference for all logic and I/O; must be low-impedance connection to minimize noise coupling. |
| 14 | VCC | Positive supply (4.5–5.5 V); requires local 0.1-μF bypass capacitor placed adjacent to pin. |
Key Features
| Feature | Design Value |
|---|---|
| TTL-compatible inputs | Accepts standard 74LS logic thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) without level translation circuitry. |
| Independent 3-state control | Four separate OE pins allow selective bus segment isolation - essential for multi-drop address/data buses. |
| Low ICC quiescent current | 80 µA max enables use in battery-backed or energy-sensitive industrial controllers without standby drain. |
| High noise immunity | Input hysteresis and 0.4-V noise margin (VIL to VIH) suppress false triggering in electrically noisy environments. |
| Robust output stage | ±35-mA absolute max output current supports short-term surge conditions during bus contention events. |
Applications
| Microcontroller Address Bus Buffering | Legacy System Bus Isolation |
|---|---|
|
Use Scenario: Isolating microcontroller address lines from multiple peripheral decoders in an 8-bit embedded system with shared memory mapping. IC Role / Device Role / Timing Role: SN74HCT125DRE4 acts as a direction-controlled, 3-state address latch driver - enabling one controller to assert addresses while peripherals tri-state their outputs. Use Value: Prevents bus contention during address decode transitions; ±6-mA drive ensures clean edges across 15-cm PCB traces loaded with 10+ decoder inputs. |
Use Scenario: Interfacing modern FPGA-based logic to legacy 74LS-based backplane systems requiring strict 5-V TTL signaling compliance. IC Role / Device Role / Timing Role: SN74HCT125DRE4 serves as a level-consistent, low-latency buffer between FPGA I/O banks and LS-family bus transceivers. Use Value: Eliminates need for discrete resistor networks or dual-supply translators; 12-ns tpd preserves setup/hold timing margins in 20-MHz bus cycles. |
| Industrial PLC I/O Expansion Module | Test Equipment Signal Routing Matrix |
|
Use Scenario: Managing parallel digital I/O expansion in programmable logic controllers where field modules share a common backplane data bus. IC Role / Device Role / Timing Role: SN74HCT125DRE4 provides channelized 3-state gating for module-selective data routing under firmware control. Use Value: Enables hot-swap-safe bus access; high-impedance state prevents backfeeding into inactive modules during configuration changes. |
Use Scenario: Constructing reconfigurable signal paths in automated test equipment that routes DUT signals to multiple measurement instruments. IC Role / Device Role / Timing Role: SN74HCT125DRE4 functions as a manually or microcontroller-programmed bus switch for multiplexing digital stimulus/response lines. Use Value: Supports glitch-free path switching via synchronized OE control; low input current (<1 µA) avoids loading upstream signal sources. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT125DR | Identical electrical specs and SOIC-14 packaging; differs only in tape-and-reel packaging variant (no E4 suffix) and RoHS finish detail. | No functional difference; both support same industrial temperature range (–40°C to 85°C) and MSL-1 reflow profile. | Select SN74HCT125DR when standard NIPDAU lead finish without E4 designation is preferred for procurement alignment. |
| 74HCT125PW,118 (Nexperia) | Same logic function and 3-state timing, but TSSOP-14 package (4.4 mm × 5.0 mm); RθJA = 152°C/W vs. 138.7°C/W for SOIC. | Smaller footprint suits space-constrained designs; higher thermal resistance requires derating above 50 mW total dissipation. | Choose 74HCT125PW,118 only when board area is constrained and thermal management accommodates higher junction rise. |
Compared with SN74HCT125DR, SN74HCT125DRE4 offers identical functionality with TI's standardized E4 RoHS-compliant finish; versus 74HCT125PW,118, it provides lower thermal resistance and proven SOIC-14 layout compatibility - making SN74HCT125DRE4 optimal for retrofitting legacy 5-V control boards.
Availability
SN74HCT125DRE4 is available at Aetrix Electronics and suitable for industrial PLC backplanes, microcontroller address bus expansion, and legacy 5-V TTL system upgrades requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74HCT125DRE4 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 50 years of industrial-grade product development.
The SN74HCT125 series belongs to TI's industry-standard 74HCT logic family - designed specifically for robust 5-V TTL-compatible interfacing in harsh industrial and automotive control environments.
FAQ
What is the operating voltage range for SN74HCT125DRE4?
The SN74HCT125DRE4 operates strictly within 4.5 V to 5.5 V. It is not rated for 3.3-V operation, and applying voltages outside this range may cause permanent damage or undefined behavior. This range ensures full compatibility with legacy 5-V TTL systems while maintaining HCMOS power efficiency - a key design constraint confirmed in Section 5.2 of the official datasheet.
Does SN74HCT125DRE4 support true bidirectional data flow?
No, SN74HCT125DRE4 is a unidirectional buffer (Y = A) with 3-state outputs - it does not auto-detect direction or contain internal bus transceivers. Bidirectional operation requires external control logic to coordinate OE signals and upstream/downstream drivers. Each channel buffers data in one direction only, as defined by its Boolean function and pinout.
What is the maximum capacitive load SN74HCT125DRE4 can drive reliably?
SN74HCT125DRE4 is characterized for CL = 50 pF and CL = 150 pF loads in its switching specifications. At 5.5 V, tpd increases from 22 ns to 42 ns when CL rises from 50 pF to 150 pF. For reliable timing, keep total trace + input capacitance ≤ 150 pF per output; exceeding this degrades edge rates and may violate setup/hold windows in synchronous systems.
How should unused inputs be handled on SN74HCT125DRE4?
All unused inputs on SN74HCT125DRE4 - including A and OE pins - must be tied to either VCC or GND. Floating inputs cause increased ICC, erratic output states, and potential latch-up. OE pins should connect to VCC via pullup resistors (e.g., 10 kΩ) to ensure high-impedance default on power-up, as explicitly required in Section 7.1 of the datasheet.
Is SN74HCT125DRE4 pin-compatible with older 74LS125 devices?
SN74HCT125DRE4 shares identical pinout and logic function with 74LS125, but differs in electrical behavior: it draws far less supply current (80 µA vs. ~19 mA), has faster propagation delay (12 ns vs. ~23 ns), and exhibits higher noise immunity due to CMOS input structure. Direct replacement is electrically safe and mechanically drop-in - verified by TI's cross-reference documentation and package drawings.
SN74HCT125DRE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74HCT125DRE4 FAQ
1.How can I place an order for SN74HCT125DRE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT125DRE4 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 SN74HCT125DRE4 reliable?
The price and inventory of SN74HCT125DRE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT125DRE4 is usually 5 days.
3.What payment methods are accepted for SN74HCT125DRE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT125DRE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT125DRE4?
SN74HCT125DRE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT125DRE4 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 SN74HCT125DRE4?
For technical support, including SN74HCT125DRE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT125DRE4 requirements.
6.How does Aetrix verify that SN74HCT125DRE4 is sourced from the original manufacturer or authorized distributors?
All SN74HCT125DRE4 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 SN74HCT125DRE4 meets industry standards.
7.What is the process for return or replacement of SN74HCT125DRE4?
All SN74HCT125DRE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT125DRE4, 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 SN74HCT125DRE4 part is unused and in its original packaging.
Return procedure for SN74HCT125DRE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
SN74HCT125DRE4 Tags
-
SN74LVC1G17DBVR
Texas Instruments
-
SN74LVC1G07DCKR
Texas Instruments
-
SN74LVC1G17DCKR
Texas Instruments
-
SN74LVC1G07DBVR
Texas Instruments
-
SN74LVC1G125DCKR
Texas Instruments
-
SN74AHCT1G126DBVR
Texas Instruments
-
SN74LVC1G125DBVR
Texas Instruments
-
SN74AHCT1G125DBVR
Texas Instruments
-
SN74LVC2G17DBVR
Texas Instruments
-
SN74LVC2G07DCKR
Texas Instruments
-
SN74LVC1G34DCKR
Texas Instruments
-
SN74LVC2G17DCKR
Texas Instruments
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
