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Texas Instruments SN74F126DR
- Part No.:
- SN74F126DR
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74F126DR.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,288
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Product details
Overview
SN74F126DR from Texas Instruments is a quadruple bus buffer gate with 3-state outputs, designed for bidirectional data bus isolation and memory address register buffering in TTL-compatible digital systems. It operates from 4.5 V to 5.5 V, delivers 6.5 ns max propagation delay at 5 V, and supports ±64 mA low-level output drive per channel.
For engineers reviewing the SN74F126DR datasheet, SN74F126DR pinout, SN74F126DR application, or SN74F126DR equivalent, key selection criteria include 3-state enable timing (tPZL/tPHZ), bus-drive capability under 50 pF load, thermal performance in SOIC-14 package, and compatibility with legacy F-series TTL logic families.
Technical Context
The SN74F126DR implements four independent noninverting buffers, each with dedicated active-high output-enable (OE) control. Its 3-state outputs support high-impedance disconnection during power-up/down when OE is pulled low via external resistor.
It adheres to F-series TTL electrical standards: VIH = 2 V min, VIL = 0.8 V max, VOL = 0.55 V max at IOL = 64 mA, and IOZH/IOZL ≤ ±50 µA in disabled state - ensuring interoperability with SN74Fxx and compatible logic families.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - ensures stable operation across standard TTL supply tolerances. |
| Max tpd | 6.5 ns at 5 V, CL = 50 pF - enables use in sub-150 MHz bus timing paths. |
| IOL / IOH | 64 mA / –15 mA - drives terminated transmission lines or multiple TTL inputs directly. |
| 3-State Leakage | ±50 µA at VO = 0.5 V / 2.7 V - minimizes bus contention current when disabled. |
| Input Thresholds | VIH = 2 V min, VIL = 0.8 V max - guarantees noise margin > 0.4 V in 5 V systems. |
| Thermal Resistance | θJA = 86°C/W (SOIC-D) - supports continuous operation up to 70°C ambient with moderate PCB copper. |
Pinout & Package
SN74F126DR is housed in a 14-pin SOIC (D) package with 1.27 mm pitch, 8.75 mm × 3.9 mm body, and 1.75 mm max height. Pin 1 identifier is marked on top-side silkscreen.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | OE (Output Enable) | Active-high control per buffer; must be pulled low externally for safe power-up high-Z state. |
| 2, 5, 11, 14 | A (Input) | Noninverting data input for corresponding buffer channel. |
| 3, 6, 12, 9 | Y (Output) | 3-state buffered output; high-impedance when OE = L. |
| 7 | GND | Ground reference for all logic and output stages. |
| 14 | VCC | Positive supply rail; decoupling capacitor required within 10 mm of pin. |
Key Features
| Feature | Design Value |
|---|---|
| Independent 3-state control | Four separate OE inputs allow selective bus segment isolation without global disable. |
| Bus-drive capability | 64 mA sink per output meets TTL fan-out requirements for up to 10 LS-TTL loads. |
| Power-up safety | OE-low default behavior prevents bus contention during supply ramp; pulldown resistor ensures defined state. |
| F-series TTL compatibility | Matched VIH/VIL, VOL/VOH, and AC timing ensure drop-in replacement for SN74F244/SN74F240 variants. |
Applications
| Memory Address Buffering | System Bus Isolation |
|---|---|
Use Scenario: Driving 16-bit address lines from microprocessor to multiple memory ICs with shared bus architecture. IC Role / Device Role / Timing Role: Noninverting buffer with per-line 3-state control isolates CPU address bus from memory decode logic during DMA cycles. Use Value: Prevents address bus contention during peripheral access; 6.5 ns tpd maintains setup/hold timing margins for 8-MHz Z80 or 68000 systems. | Use Scenario: Separating CPU data bus from peripheral controller bus in industrial PLC backplane designs. IC Role / Device Role / Timing Role: Bidirectional bus buffer enabling controlled data flow between two asynchronous clock domains using OE gating. Use Value: Eliminates need for external bus transceivers; ±64 mA drive sustains signal integrity over 10 cm PCB traces at 5 V. |
| Legacy System Repair | TTL Logic Level Translation |
Use Scenario: Replacing obsolete SN74F244 in vintage test equipment where board layout prohibits redesign. IC Role / Device Role / Timing Role: Pin-compatible functional substitute for quad buffer with 3-state outputs in repair scenarios. Use Value: Maintains identical timing (tPLH/tPHL), voltage thresholds, and drive strength - no firmware or timing adjustments required. | Use Scenario: Interfacing 5 V TTL logic to older 3.3 V or mixed-voltage peripherals with level-shifting constraints. IC Role / Device Role / Timing Role: Voltage-tolerant input stage (–1.2 V to 7 V) allows safe connection to higher-voltage sources while driving 5 V loads. Use Value: Enables direct connection to 5 V buses without external clamping diodes; IOZ leakage < 50 µA avoids loading downstream CMOS inputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74F244N | Octal (8-channel) version in PDIP-20; identical per-channel specs but double density. | Requires PCB footprint change; suitable only when additional buffer channels are needed. | Select when system requires eight isolated bus lines and space permits larger package. |
| SN74LS126N | Lower drive (IOL = 24 mA), slower tpd (15 ns), higher VIH (2.0 V), same SOIC-14 pinout. | Compatible pinout but reduced speed and drive; acceptable only in non-critical timing paths. | Choose only if power consumption is prioritized over speed and legacy LS-TTL systems demand exact match. |
Compared with SN74F244N and SN74LS126N, the SN74F126DR offers optimal balance of speed (6.5 ns), drive strength (64 mA), and SOIC-14 footprint - making it the preferred choice for space-constrained, high-speed bus isolation where quad-channel count suffices.
Availability
SN74F126DR is available at Aetrix Electronics and suitable for memory subsystem design, industrial backplane bus isolation, and legacy TTL system repair requiring stable component supply and long-term obsolescence mitigation.
Supply support for SN74F126DR 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 solutions for industrial, automotive, and communications markets.
The SN74F126DR belongs to TI's legacy F-series TTL logic family, engineered for high-speed, robust bus interfacing in systems demanding deterministic timing and proven reliability across temperature extremes.
FAQ
What is the maximum operating temperature range for the SN74F126DR?
The SN74F126DR is rated for operation from 0°C to +70°C ambient temperature. This commercial-grade specification aligns with standard TTL logic requirements and is validated across the full recommended VCC range (4.5 V to 5.5 V). Thermal derating is not required within this range when θJA = 86°C/W is respected with adequate PCB copper area.
Does the SN74F126DR require external pull-down resistors on OE pins?
Yes - to ensure high-impedance outputs during power-up or power-down, each OE pin of the SN74F126DR must be tied to GND through an external pulldown resistor. The minimum resistance value depends on the driver's current-sourcing capability; typical values range from 1 kΩ to 10 kΩ. This prevents undefined bus states before system initialization completes.
Can the SN74F126DR drive a 50-pF capacitive load reliably?
Yes - the SN74F126DR's switching characteristics are explicitly characterized at CL = 50 pF and RL = 500 Ω, with tPLH/tPHL specified up to 8.5 ns across temperature. Its 64 mA output sink capability ensures clean edge transitions into this load, meeting setup/hold timing for synchronous interfaces like Z80 or 68000 address/data buses.
Is the SN74F126DR pin-compatible with other 74F-series quad buffers?
Yes - the SN74F126DR shares identical pinout and function mapping with SN74F125 (inverting variant) and SN74F240/244 (octal versions in different packages). Its SOIC-14 footprint matches industry-standard D-package layouts, enabling direct substitution where quad-channel count and noninverting logic are required.
What is the absolute maximum input voltage rating for the SN74F126DR?
The SN74F126DR supports an absolute maximum input voltage range of –1.2 V to +7 V, as specified in its datasheet. This tolerance allows safe interfacing with higher-voltage sources or transient conditions, provided input current remains within –30 mA to +5 mA limits. Exceeding these ratings risks permanent damage even if duration is brief.
SN74F126DR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74F
- Package/Case:
- 14-SOIC (0.154", 3.90mm 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:
- 15mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74F126DR FAQ
1.How can I place an order for SN74F126DR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74F126DR 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 SN74F126DR reliable?
The price and inventory of SN74F126DR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74F126DR is usually 5 days.
3.What payment methods are accepted for SN74F126DR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74F126DR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74F126DR?
SN74F126DR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74F126DR 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 SN74F126DR?
For technical support, including SN74F126DR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74F126DR requirements.
6.How does Aetrix verify that SN74F126DR is sourced from the original manufacturer or authorized distributors?
All SN74F126DR 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 SN74F126DR meets industry standards.
7.What is the process for return or replacement of SN74F126DR?
All SN74F126DR units undergo pre-shipment inspection (PSI). If there is an issue with SN74F126DR, 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 SN74F126DR part is unused and in its original packaging.
Return procedure for SN74F126DR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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