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onsemi DM74LS126AN
- Part No.:
- DM74LS126AN
- Manufacturer:
- onsemi
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
DM74LS126AN.pdf
- Description:
- IC BUF NON-INVERT 5.25V 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,275
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Product details
Overview
DM74LS126AN from Fairchild Semiconductor is a quad non-inverting 3-STATE buffer IC in 14-lead PDIP package, operating at 4.75–5.25 V supply, with 24 mA low-level output drive, 2.4 V minimum VOH, and 0.35 V maximum VOL. It enables bus-oriented digital systems by allowing multiple drivers to share a common data line without contention.
For engineers reviewing the DM74LS126AN datasheet, pinout, applications, or equivalent options, key selection criteria include 3-STATE enable timing (tPZH ≤ 36 ns), disable asymmetry (tPHZ = tPLZ = 25 ns), bus-drive capability without pull-ups, and compatibility with standard LS logic families.
Technical Context
The DM74LS126AN implements four independent buffer gates with individual active-high enable inputs (C), each driving a 3-STATE output (Y) that mirrors input A. Its TTL-compatible input thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and LS-output impedance characteristics ensure interoperability with 74LS, 74S, and 74F series devices.
Output disable occurs faster than enable (tPHZ/tPLZ = 25 ns vs. tPZH/tPZL up to 42 ns), reducing bus contention risk during state transitions. The device operates only within 0°C to +70°C free-air temperature range and requires no external termination resistors for bus loading.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.75–5.25 V - Ensures stable operation under standard TTL rail tolerances. |
| VOH / VOL | ≥2.4 V / ≤0.35 V - Guarantees noise margin >0.4 V with LS loads. |
| IOL / IOH | 24 mA / −2.6 mA - Drives up to 20 LS TTL inputs directly without external buffers. |
| tPLH / tPHL | 15–21 ns / 18–22 ns - Supports 25+ MHz bus clocking with deterministic propagation. |
| tPZH / tPZL | 30–36 ns / 30–42 ns - Defines worst-case enable delay for synchronous bus arbitration. |
| tPHZ / tPLZ | 25 ns - Fast disable ensures minimal bus conflict window during output release. |
| Operating Temperature | 0°C to +70°C - Qualified for commercial-grade embedded control and instrumentation. |
Pinout & Package
DM74LS126AN is housed in a 14-lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300" wide, with through-hole mounting and industry-standard lead pitch (0.100").
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 4, 10, 13 | Input A | Four independent non-inverting data inputs (A1–A4). |
| 2, 5, 9, 12 | Enable C | Active-HIGH 3-STATE enable controls for Y1–Y4 respectively. |
| 3, 6, 8, 11 | Output Y | Four buffered, 3-STATE outputs mirroring respective A inputs when enabled. |
| 7 | GND | Ground reference for all logic and output stages. |
| 14 | VCC | +5 V power supply for internal TTL circuitry and output drivers. |
Key Features
| Feature | Design Value |
|---|---|
| Individual 3-STATE Enables | Each of four buffers has dedicated active-HIGH enable, enabling selective bus access per channel. |
| Faster Output Disable | Disable time (25 ns) < enable time (≤42 ns), minimizing bus contention during multi-driver handoff. |
| High Sink Current | 24 mA IOL supports direct drive of 20 LS TTL loads - eliminates need for external bus drivers. |
| Bus-Compatible Output Impedance | Outputs present near-infinite impedance when disabled (IOZL/IOZH ≤ ±20 µA), preventing signal loading or back-driving. |
| Standard LS Logic Compatibility | VIH/VIL thresholds and VOH/VOL levels match 74LS family specs, ensuring plug-in replacement in legacy designs. |
Applications
| Microprocessor Bus Interface | Data Acquisition System |
|---|---|
Use Scenario: Bidirectional address/data bus isolation between CPU and peripheral ICs in 8-bit microcontroller systems. IC Role / Device Role / Timing Role: DM74LS126AN acts as a unidirectional 3-STATE buffer for address latching and peripheral enable control, synchronized to WR/RD strobes. Use Value: Eliminates bus contention during memory-mapped I/O cycles via precise enable/disable timing (tPHZ = 25 ns). | Use Scenario: Multiplexed analog-to-digital converter (ADC) output buffering before microcontroller sampling. IC Role / Device Role / Timing Role: DM74LS126AN isolates ADC output lines from shared data bus until conversion completes and CS is asserted. Use Value: Prevents signal corruption during ADC settling by presenting Hi-Z state until valid data is ready. |
| Industrial Control Panel | Legacy Instrumentation Backplane |
Use Scenario: LED display driver interface where multiple 7-segment decoders share a common segment bus. IC Role / Device Role / Timing Role: DM74LS126AN enables one decoder's outputs at a time while others remain Hi-Z, supporting multiplexed digit scanning. Use Value: Reduces component count by replacing discrete transistors or open-collector buffers with integrated 24 mA sink capability. | Use Scenario: Signal conditioning and routing on modular test equipment backplanes using standardized 100-pin DIN connectors. IC Role / Device Role / Timing Role: DM74LS126AN provides level-shifted, isolated data path control between card-edge logic and backplane bus lines. Use Value: Maintains signal integrity across long traces via low-capacitance Hi-Z disconnect and robust 5 V logic margins. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar 3-STATE buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS126N | Identical electrical specs and pinout; manufactured by Texas Instruments with same LS process and timing. | No functional difference; validated in identical bus-interface roles across industrial control schematics. | Select SN74LS126N when TI-sourced components are required for BOM consistency or dual-sourcing programs. |
| MC74LS126N | Slight variation in tPLH/tPHL (16–23 ns); otherwise matches VOH/VOL, IOL/IOH, and enable/disable timing. | Same bus arbitration behavior; minor propagation skew may affect high-speed synchronous designs above 20 MHz. | Choose MC74LS126N for Motorola-design legacy systems or where second-source qualification mandates ON Semiconductor parts. |
Compared with SN74LS126N and MC74LS126N, the DM74LS126AN offers identical functional behavior and timing envelope, but differs in manufacturer-specific process calibration - making it suitable for drop-in replacement where sourcing flexibility or obsolescence mitigation is required.
Availability
DM74LS126AN is available at Aetrix Electronics and suitable for microprocessor bus interfaces, data acquisition systems, industrial control panels, and legacy instrumentation backplanes requiring stable component supply and long-term obsolescence support.
Supply support for DM74LS126AN 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
Fairchild Semiconductor was a U.S.-based designer and manufacturer of analog and mixed-signal ICs, acquired by ON Semiconductor in 2016; its legacy logic portfolio remains widely deployed in industrial and embedded systems.
The DM74LS126AN belongs to Fairchild's 74LS logic family, engineered specifically for reliable bus interfacing in commercial-temperature embedded controllers and instrumentation where 3-STATE control and TTL compatibility are essential.
FAQ
What is the maximum operating temperature range for the DM74LS126AN?
The DM74LS126AN is rated for operation from 0°C to +70°C ambient temperature. This commercial-grade specification aligns with standard 74LS logic requirements and ensures reliability in non-automotive, non-military embedded applications such as industrial control panels and test equipment. Operation outside this range may cause timing violations or increased leakage current.
Does the DM74LS126AN support bidirectional data flow?
No, the DM74LS126AN is a unidirectional non-inverting buffer with separate input (A), enable (C), and output (Y) terminals per channel. It does not implement bidirectional switching or automatic direction control. For bidirectional bus transceivers, consider the DM74LS245 or equivalent octal transceiver.
Can the DM74LS126AN drive standard TTL loads directly?
Yes, the DM74LS126AN can drive up to 20 standard TTL (74LS) inputs directly due to its 24 mA low-level output current (IOL) and −2.6 mA high-level output current (IOH). Its VOH ≥ 2.4 V and VOL ≤ 0.35 V meet LS-family interface requirements without external pull-up or pull-down resistors.
What is the purpose of the faster disable time in the DM74LS126AN?
The DM74LS126AN features asymmetric timing: output disable (tPHZ/tPLZ = 25 ns) is faster than enable (tPZH/tPZL up to 42 ns). This design minimizes bus contention when multiple DM74LS126AN devices share a common line, ensuring one driver releases the bus before another asserts control.
Is the DM74LS126AN pin-compatible with other 74LS-series quad buffers?
Yes, the DM74LS126AN uses the standard 14-pin DIP pinout defined for 74LS126 devices, matching SN74LS126N and MC74LS126N. All share identical pin assignments for VCC, GND, A/C/Y signals across channels 1–4, enabling direct physical replacement in existing PCB layouts.
DM74LS126AN Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- Series:
- 74LS
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Logic Type:
- Buffer, Non-Inverting
- Number of Elements:
- 4
- Number of Bits per Element:
- 1
- Input Type:
- -
- Output Type:
- -
- Current - Output High, Low:
- 2.6mA, 24mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-MDIP
DM74LS126AN FAQ
1.How can I place an order for DM74LS126AN through Aetrix?
Please submit a Request for Quotation (RFQ) for DM74LS126AN 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 DM74LS126AN reliable?
The price and inventory of DM74LS126AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DM74LS126AN is usually 5 days.
3.What payment methods are accepted for DM74LS126AN?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DM74LS126AN transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DM74LS126AN?
DM74LS126AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DM74LS126AN 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 DM74LS126AN?
For technical support, including DM74LS126AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DM74LS126AN requirements.
6.How does Aetrix verify that DM74LS126AN is sourced from the original manufacturer or authorized distributors?
All DM74LS126AN 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 DM74LS126AN meets industry standards.
7.What is the process for return or replacement of DM74LS126AN?
All DM74LS126AN units undergo pre-shipment inspection (PSI). If there is an issue with DM74LS126AN, 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 DM74LS126AN part is unused and in its original packaging.
Return procedure for DM74LS126AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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