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Texas Instruments CD74HC126E
- Part No.:
- CD74HC126E
- Manufacturer:
- Texas Instruments
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
CD74HC126E.pdf
- Description:
- IC BUFFER NON-INVERT 6V 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:909
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Product details
Overview
CD74HC126E from Texas Instruments is a quadruple non-inverting buffer with 3-state outputs, designed for digital signal routing and bus isolation in industrial and embedded systems. It operates across 2 V to 6 V supply, supports –55°C to +125°C temperature range, delivers propagation delay as low as 17 ns at 6 V, and drives up to 10 LSTTL loads - enabling robust data enable control in multi-channel bus architectures.
For engineers reviewing the CD74HC126E datasheet, CD74HC126E pinout, CD74HC126E application, or CD74HC126E equivalent, key selection criteria include its 14-pin PDIP package, independent per-channel 3-state control, guaranteed VOH ≥ 5.48 V / VOL ≤ 0.4 V at 6 V/7.8 mA, and compatibility with HC logic families requiring fanout scalability and wide-voltage operation.
Technical Context
This device implements four electrically isolated buffer channels, each performing Y = A (positive-logic identity function) with separate output-enable (OE) inputs. Each channel's output enters high-impedance state when OE is low, allowing bidirectional bus sharing without contention.
It uses standard CMOS inputs with 10 pF input capacitance and balanced CMOS 3-state outputs capable of sourcing/sinking ±7.8 mA while maintaining VOH/VOL specs under load - critical for driving capacitive traces or light CMOS loads in noise-sensitive environments.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 2 V to 6 V - enables direct interface with 3.3 V and 5 V logic domains without level shifters |
| Operating Temperature | –55°C to +125°C - qualified for extended industrial and automotive under-hood applications |
| Propagation Delay | 17 ns max at 6 V, CL = 50 pF - ensures timing predictability in synchronous bus gating |
| Output Drive | ±7.8 mA at 6 V - sufficient to drive 10 LSTTL loads or moderate PCB trace capacitance |
| Input Capacitance | 10 pF - minimizes loading on upstream drivers and preserves signal edge integrity |
| Three-State Leakage | ±10 µA max at –55°C to +125°C - maintains high-impedance integrity during power-down or bus arbitration |
| Power Dissipation Cap. | 30 pF per gate - used to calculate dynamic power consumption in high-frequency switching scenarios |
Pinout & Package
CD74HC126E is housed in a 14-pin Plastic Dual In-line Package (PDIP) with nominal body size 19.30 mm × 6.40 mm, through-hole mounting, and RoHS-compliant NiPdAu lead finish.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE, 3OE, 4OE | Active-Low Output Enable | Individually disables corresponding buffer output into high-Z state; allows per-channel bus arbitration |
| 1A, 2A, 3A, 4A | Buffer Input | Standard CMOS input accepting 0–VCC logic levels; requires termination if unused |
| 1Y, 2Y, 3Y, 4Y | Buffer Output | 3-state CMOS output replicating input when OE high; floats when OE low |
| VCC (Pin 14) | Positive Supply | Primary power rail; requires local 0.1 µF bypass capacitor for noise suppression |
| GND (Pin 7) | Ground Reference | Return path for all I/O and supply currents; must be low-impedance connection |
Key Features
| Feature | Design Value |
|---|---|
| Independent 3-state control per channel | Enables selective activation of individual data lines on shared buses without external logic |
| Balanced CMOS output drive | Sources and sinks matched current (±7.8 mA), minimizing ground bounce and improving signal symmetry |
| Wide supply voltage range (2–6 V) | Supports mixed-voltage system integration - e.g., interfacing 3.3 V microcontrollers to 5 V peripherals |
| Low input leakage (±1 µA max) | Reduces static power draw and prevents unintended logic transitions in battery-powered or high-impedance nodes |
| Clamp diode protection | Withstands ±2000 V HBM ESD - enhances reliability during handling and board assembly |
Applications
| Industrial Bus Isolation | Microcontroller Peripheral Enable |
|---|---|
Use Scenario: Isolating multiple sensor modules on a shared RS-485 or parallel status bus to prevent signal contention during fault conditions. IC Role / Device Role / Timing Role: CD74HC126E acts as a digitally controlled gate, enabling/disabling sensor data paths via independent OE signals synchronized to controller timing. Use Value: Eliminates need for discrete MOSFET switches or complex bus transceivers while maintaining signal integrity across –55°C to +125°C operating range. | Use Scenario: Enabling/disabling SPI or parallel LCD interface lines from an MCU to reduce standby current and avoid floating inputs on unpowered peripherals. IC Role / Device Role / Timing Role: CD74HC126E serves as a programmable signal buffer, asserting active-high data only when peripheral is powered and ready. Use Value: Prevents back-driving and latch-up in unpowered peripherals, leveraging per-channel 3-state control to match dynamic power sequencing requirements. |
| Legacy System Signal Conditioning | Test Equipment Signal Routing |
Use Scenario: Adapting TTL-level control signals from aging PLC I/O cards to modern 3.3 V FPGA-based controllers in retrofit installations. IC Role / Device Role / Timing Role: CD74HC126E functions as a level-tolerant repeater, translating 5 V logic edges while providing fanout expansion and noise margin improvement. Use Value: Achieves interoperability without custom level-shifter ICs, using native 2–6 V supply compatibility and 10 LSTTL fanout capability. | Use Scenario: Multiplexing stimulus signals from a single pattern generator to multiple DUT inputs in automated test fixtures. IC Role / Device Role / Timing Role: CD74HC126E operates as a gated signal distributor, where OE pins are sequenced to route test vectors to specific pins under software control. Use Value: Enables flexible, reconfigurable test hardware using low-cost PDIP packaging and deterministic propagation delay (≤36 ns). |
Equivalent & Alternatives
The following parts are listed as comparable options for similar buffer-with-3-state-output applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74HC125N | Same 14-pin PDIP package and 2–6 V operation, but features active-high OE (vs. active-low OE on CD74HC126E) | Requires inverted enable logic; not drop-in compatible without schematic modification | Select when system control logic natively provides high-active gating signals |
| MC74HC126N | Pin-compatible and functionally identical, but manufactured by ON Semiconductor with identical electrical specs and –55°C to +125°C rating | No functional or layout impact; differs only in branding and traceability chain | Preferred for dual-sourcing strategies where TI second-source qualification is required |
Compared with SN74HC125N and MC74HC126N, CD74HC126E offers native active-low OE control ideal for systems using open-collector or pull-up-based enable busing, retains full pin-and-function equivalence with MC74HC126N for seamless second-source substitution, and delivers identical timing and drive performance across its full industrial temperature range.
Availability
CD74HC126E is available at Aetrix Electronics and suitable for industrial bus isolation, microcontroller peripheral enable, legacy system signal conditioning, and test equipment signal routing requiring stable component supply across extended temperature ranges.
Supply support for CD74HC126E 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 90 years of innovation in industrial, automotive, and communications markets.
CD74HC126E belongs to the CDx4HC126 family of high-speed CMOS buffers, engineered specifically for reliable digital signal routing, bus contention prevention, and voltage-flexible interface bridging in harsh-environment applications.
FAQ
What is the maximum capacitive load CD74HC126E can drive while meeting datasheet timing specs?
CD74HC126E is characterized for CL ≤ 50 pF in switching specifications, with propagation delay (tpd) and transition time (tt) guaranteed at that load. Driving >50 pF increases delay and edge degradation; for 70 pF loads, timing margins shrink significantly. To maintain spec compliance, keep total trace + input capacitance ≤ 50 pF or add series resistance to limit slew rate and prevent ringing - verified in Section 6.6 of the CD74HC126E datasheet.
Does CD74HC126E support mixed-voltage operation between input and output sides?
No, CD74HC126E does not support true mixed-voltage I/O. Its inputs and outputs reference the same VCC rail (2–6 V). While it accepts 3.3 V or 5 V logic levels when VCC is set accordingly, it cannot translate between different supply domains - e.g., 3.3 V input to 5 V output - without external level-shifting circuitry. This limitation is inherent to its single-supply CMOS architecture, as confirmed in Section 6.3 Recommended Operating Conditions.
How should unused inputs and outputs be handled on CD74HC126E?
Unused inputs on CD74HC126E must be terminated to VCC or GND - never left floating - to prevent oscillation and excessive current draw due to undefined threshold crossing. Unused outputs may be left unconnected (floating), as their 3-state behavior isolates them when OE is inactive. This guidance is explicitly stated in Section 9.1 Application Information and Figure 11-1 layout example of the CD74HC126E datasheet.
Is CD74HC126E suitable for automotive under-hood applications?
Yes, CD74HC126E is rated for –55°C to +125°C operating temperature and packaged in PDIP with qualified materials per TI's automotive-grade process flow. Though not AEC-Q100 certified as a standalone part, its extended temperature range, 2000 V HBM ESD rating, and robustness against thermal cycling make it suitable for non-safety-critical under-hood functions like sensor interface buffering or diagnostic line gating - provided system-level validation confirms compliance with end-equipment requirements.
What decoupling capacitance is recommended for CD74HC126E?
A 0.1 µF ceramic capacitor placed as close as possible between VCC (Pin 14) and GND (Pin 7) is explicitly recommended in Section 10 Power Supply Recommendations and Figure 11-1 of the CD74HC126E datasheet. For systems with higher noise susceptibility, paralleling a 1 µF capacitor is acceptable - but physical proximity to the IC pins remains critical to suppress high-frequency supply transients affecting output stability.
CD74HC126E Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
CD74HC126E FAQ
1.How can I place an order for CD74HC126E through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC126E 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 CD74HC126E reliable?
The price and inventory of CD74HC126E are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC126E is usually 5 days.
3.What payment methods are accepted for CD74HC126E?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC126E transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC126E?
CD74HC126E orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC126E 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 CD74HC126E?
For technical support, including CD74HC126E datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC126E requirements.
6.How does Aetrix verify that CD74HC126E is sourced from the original manufacturer or authorized distributors?
All CD74HC126E 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 CD74HC126E meets industry standards.
7.What is the process for return or replacement of CD74HC126E?
All CD74HC126E units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC126E, 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 CD74HC126E part is unused and in its original packaging.
Return procedure for CD74HC126E:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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