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Texas Instruments SN74HCT125NG4
- Part No.:
- SN74HCT125NG4
- Manufacturer:
- Texas Instruments
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74HCT125NG4.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,925
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Product details
Overview
SN74HCT125NG4 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. It serves as a bidirectional data isolator in microcontroller peripheral buses and memory address latching circuits.
For engineers reviewing the SN74HCT125NG4 datasheet, SN74HCT125NG4 pinout, SN74HCT125NG4 application, or SN74HCT125NG4 equivalent, key selection criteria include 3-state output timing (ten/tdis ≤ 35 ns), input voltage compatibility (VIH = 2 V, VIL = 0.8 V), thermal resistance (RθJA = 75.3 °C/W), and PDIP-14 package mechanical fit for legacy through-hole designs.
Technical Context
This device implements four independent non-inverting buffers (Y = A) with individual 3-state output-enable (OE) inputs. Each channel transitions to high-impedance when OE is high, enabling shared-bus arbitration without external logic.
It uses HCMOS technology with TTL-level input thresholds, ensuring interoperability with legacy 5-V logic families. The design supports CL = 50 pF loads with tpd = 10–22 ns across VCC = 4.5–5.5 V and TA = –40 to 85 °C, and maintains low ICC ≤ 80 µA in quiescent state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures stable operation across industrial 5-V rail tolerances. |
| Propagation Delay (tpd) | 10 ns min / 22 ns max at VCC = 5.5 V, CL = 50 pF - Enables reliable timing in 25-MHz bus systems. |
| Output Drive | ±6 mA at VCC = 5 V - Sufficient to drive 15 LSTTL loads directly without buffering. |
| Input Thresholds | VIH = 2.0 V, VIL = 0.8 V - Guarantees robust noise margin and compatibility with standard TTL outputs. |
| Quiescent Current (ICC) | 80 µA max - Minimizes standby power in battery-backed or energy-sensitive applications. |
| Off-State Leakage (IOZ) | ±5 µA max at VCC = 5.5 V - Prevents signal corruption on shared buses during disable. |
| Thermal Resistance (RθJA) | 75.3 °C/W (PDIP-14) - Determines maximum power dissipation before junction temperature exceeds 150 °C. |
Pinout & Package
SN74HCT125NG4 is housed in a 14-pin plastic dual in-line package (PDIP), with nominal body size 19.31 mm × 6.35 mm and 2.54-mm lead pitch. The package is through-hole mountable, RoHS-compliant, and rated for –40 °C to +85 °C operation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | Output Enable (1OE, 2OE, 3OE, 4OE) | Active-low control: OE = low enables Y = A; OE = high forces high-impedance output. |
| 2, 5, 11, 14 | Input (1A, 2A, 3A, 4A) | TTL-compatible digital input; VIH ≥ 2.0 V, VIL ≤ 0.8 V ensures reliable logic recognition. |
| 3, 6, 12, 9 | Output (1Y, 2Y, 3Y, 4Y) | 3-state buffered output; drives bus lines or memory address registers with ±6-mA capability. |
| 7 | GND | Ground reference for all internal circuitry and I/O; must be low-impedance connection. |
| 14 | VCC | Positive supply terminal; requires local 0.1-µF bypass capacitor to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Independent 3-state control per buffer | Enables selective bus isolation without gating logic or external OE multiplexing. |
| TTL-compatible input thresholds | Eliminates need for level-shifting when interfacing with legacy 5-V microcontrollers or peripherals. |
| Low quiescent current (80 µA max) | Reduces system-level standby power in always-on embedded controllers and instrumentation. |
| High-output drive (±6 mA) | Directly interfaces with multiple LSTTL loads or long PCB traces without fanout buffers. |
| Controlled transition times (7–17 ns) | Minimizes EMI and crosstalk in dense mixed-signal layouts while meeting setup/hold timing. |
Applications
| Microcontroller Peripheral Bus Isolation | Memory Address Latching |
|---|---|
|
Use Scenario: Isolating GPIO expansion ports between an MCU and multiple SPI/I²C peripherals sharing a common bus. IC Role / Device Role / Timing Role: Acts as direction-controlled buffer to prevent bus contention during multi-peripheral access. Use Value: Enables deterministic bus arbitration using discrete OE signals, eliminating software delays or external bus switches. |
Use Scenario: Driving 16-bit address lines from a microprocessor to multiple SRAM or EPROM chips. IC Role / Device Role / Timing Role: Buffers and gates address signals with precise enable timing synchronized to memory read/write strobes. Use Value: Maintains signal integrity over longer trace lengths and reduces loading on the CPU address bus. |
| Legacy System Logic Level Translation | Industrial Control Signal Distribution |
|
Use Scenario: Interfacing modern 5-V microcontrollers with older TTL-based instrumentation modules. IC Role / Device Role / Timing Role: Provides voltage-threshold matching and drive strength translation without active level shifters. Use Value: Preserves timing margins (tpd ≤ 22 ns) while ensuring VIH/VIL compatibility across heterogeneous logic families. |
Use Scenario: Distributing enable/control signals from a PLC CPU to multiple I/O modules in factory automation racks. IC Role / Device Role / Timing Role: Buffers and fans out discrete control signals with high noise immunity and load tolerance. Use Value: Supports up to 15 LSTTL loads per channel, reducing need for additional driver stages in modular backplanes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HCT244N | Octal (8-channel) configuration, identical VCC range, tpd = 11–24 ns, same PDIP-20 package. | Higher channel count suits wider data buses; requires larger PCB footprint and different pinout. | Select when expanding from 4- to 8-bit bus width; not pin-compatible with SN74HCT125NG4. |
| 74ACT125N | Faster tpd = 7–14 ns, higher ICC = 2 mA typical, 4.5–5.5 V supply, same PDIP-14 package. | Better timing performance but increased power draw; less suitable for low-power standby modes. | Choose for high-speed timing-critical paths where 80-µA quiescent current is not required. |
Compared with SN74HCT125NG4, SN74HCT244N offers double channel density at the cost of layout redesign, while 74ACT125N trades lower power for faster switching-making SN74HCT125NG4 optimal for balanced speed, power, and footprint in legacy 4-bit bus isolation.
Availability
SN74HCT125NG4 is available at Aetrix Electronics and suitable for industrial control systems, legacy instrumentation upgrades, and microcontroller peripheral interface designs requiring stable component supply and long-term obsolescence management.
Supply support for SN74HCT125NG4 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 specializing in analog, embedded processing, and logic solutions, with over 90 years of innovation in industrial and automotive electronics.
SN74HCT125NG4 belongs to TI's 74HCT logic family, designed specifically for TTL-to-CMOS interfacing in industrial and commercial 5-V systems requiring low power, high noise immunity, and guaranteed 3-state behavior.
FAQ
What is the recommended bypass capacitor for SN74HCT125NG4?
A 0.1-µF ceramic capacitor is recommended directly between VCC and GND pins of SN74HCT125NG4 to suppress high-frequency switching noise. For enhanced broadband filtering, TI recommends paralleling it with a 1-µF capacitor, both placed as close as possible to the device's power terminals to minimize loop inductance and ensure stable operation under dynamic load conditions.
Can SN74HCT125NG4 operate at 3.3 V?
No, SN74HCT125NG4 is not specified for 3.3-V operation. Its recommended operating voltage range is strictly 4.5 V to 5.5 V, and its input thresholds (VIH = 2.0 V, VIL = 0.8 V) are optimized for 5-V TTL compatibility. Operating below 4.5 V may result in undefined logic states, increased propagation delay, or failure to meet output drive specifications.
How should unused inputs be handled on SN74HCT125NG4?
All unused inputs on SN74HCT125NG4-including OE and A pins-must be tied to either VCC or GND to prevent floating states that cause excessive current draw or erratic output behavior. TI specifically recommends connecting unused OE inputs to VCC via a pullup resistor to guarantee high-impedance output during power-up or power-down sequences.
What is the maximum capacitive load SN74HCT125NG4 can drive reliably?
SN74HCT125NG4 is characterized for CL = 50 pF and CL = 150 pF loads, with tpd increasing from 10–22 ns to 16–48 ns respectively. While it can drive heavier loads, timing margins degrade beyond 150 pF; for >150-pF applications, TI advises verifying signal integrity via board-level testing or adding series termination to limit ringing and overshoot.
Is SN74HCT125NG4 RoHS compliant?
Yes, SN74HCT125NG4 is RoHS compliant, as confirmed in TI's official packaging addendum. The device uses NiPdAu (nickel-palladium-gold) or NiPdAu/Sn (tin) lead finish, meets JEDEC MSL Level-1 requirements, and carries full exemption documentation for lead content in solderable terminations per EU Directive 2011/65/EU.
SN74HCT125NG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Discontinued at Digi-Key
- 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:
- Through Hole
- Supplier Device Package:
- 14-PDIP
SN74HCT125NG4 FAQ
1.How can I place an order for SN74HCT125NG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT125NG4 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 SN74HCT125NG4 reliable?
The price and inventory of SN74HCT125NG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT125NG4 is usually 5 days.
3.What payment methods are accepted for SN74HCT125NG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT125NG4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT125NG4?
SN74HCT125NG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT125NG4 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 SN74HCT125NG4?
For technical support, including SN74HCT125NG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT125NG4 requirements.
6.How does Aetrix verify that SN74HCT125NG4 is sourced from the original manufacturer or authorized distributors?
All SN74HCT125NG4 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 SN74HCT125NG4 meets industry standards.
7.What is the process for return or replacement of SN74HCT125NG4?
All SN74HCT125NG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT125NG4, 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 SN74HCT125NG4 part is unused and in its original packaging.
Return procedure for SN74HCT125NG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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