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Texas Instruments CD74HC126M
- Part No.:
- CD74HC126M
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HC126M.pdf
- Description:
- IC BUFFER NON-INVERT 6V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,107
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Product details
Overview
CD74HC126M from Texas Instruments is a quadruple non-inverting buffer with 3-state outputs, designed for digital signal routing and bus isolation in industrial control and embedded systems. It operates across 2 V–6 V supply, supports –55°C to +125°C temperature range, delivers ≤30 ns propagation delay at 4.5 V, and drives up to 10 LSTTL loads.
For engineers reviewing the CD74HC126M datasheet, CD74HC126M pinout, CD74HC126M application, or CD74HC126M equivalent, this page provides verified functional identity, SOIC-14 package mapping, 3-state timing behavior, thermal derating guidance, and validated alternative options for bus enable logic design.
Technical Context
The CD74HC126M implements four independent CMOS buffer channels, each performing Y = A (positive-logic identity function) with separate active-low output-enable (OE) control. Its balanced 3-state outputs support bidirectional current sourcing/sinking up to ±35 mA per channel while maintaining high-impedance leakage < ±10 µA at 6 V.
It uses standard CMOS inputs with VIH/VIL thresholds scaling linearly with VCC (e.g., VIH = 3.15 V at 4.5 V), requires input transition times ≤500 ns at 4.5 V to prevent shoot-through, and features integrated clamp diodes on all I/O pins for ESD protection per HBM ±2000 V.
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 families without level shifters |
| Operating temperature | –55°C to +125°C - qualified for extended industrial and automotive under-hood environments |
| Propagation delay | 25 ns typical at 4.5 V, CL = 50 pF - ensures reliable timing in 20 MHz+ synchronous bus applications |
| Output drive | ±6 mA at VOH/VOL = 3.98 V/0.33 V (4.5 V) - sufficient to drive 10 LSTTL loads or moderate capacitive loads ≤70 pF |
| 3-state leakage | ±5 µA max at 6 V - minimizes standby current in powered-down bus segments |
| Input capacitance | 10 pF - low loading preserves signal integrity on high-speed control lines |
| Power dissipation | 30 pF typical Cpd per gate - enables accurate dynamic power estimation in battery-sensitive designs |
Pinout & Package
CD74HC126M is housed in a 14-pin SOIC (D) package measuring 8.70 mm × 3.90 mm, with gull-wing leads, RoHS-compliant NiPdAu plating, and moisture sensitivity level 1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE, 3OE, 4OE | Active-low output enable | Asserting low enables corresponding buffer output; high places output in high-impedance state for bus sharing |
| 1A, 2A, 3A, 4A | Buffer input | CMOS-compatible input accepting 0–VCC logic levels; must be terminated to VCC or GND if unused |
| 1Y, 2Y, 3Y, 4Y | Buffer output | Non-inverting output with 3-state capability; capable of sourcing/sinking ±6 mA while maintaining VOL ≤0.33 V |
| VCC (Pin 14) | Positive supply | Primary power rail; requires local 0.1 µF bypass capacitor placed adjacent to pin for noise suppression |
| GND (Pin 7) | Ground reference | Common return path for all channels; ties to system ground plane to minimize switching noise coupling |
Key Features
| Feature | Design Value |
|---|---|
| Quadruple 3-state buffers | Four independent channels allow simultaneous enable/disable control of parallel data paths without inter-channel crosstalk |
| Wide supply range (2–6 V) | Supports mixed-voltage system integration-e.g., interfacing 3.3 V microcontrollers to 5 V peripherals |
| High-temperature operation | Rated for –55°C to +125°C ambient enables use in motor drives, power supplies, and outdoor industrial enclosures |
| Low dynamic power | Typical ICC = 8 µA at 6 V, 25°C - reduces quiescent load on battery-backed or energy-harvested subsystems |
| ESD robustness | HBM ±2000 V rating - meets IEC 61000-4-2 Level 2 requirements for board-level ESD immunity |
Applications
| Industrial Bus Isolation | Microcontroller GPIO Expansion |
|---|---|
Use Scenario: Isolating legacy 5 V parallel address/data buses during hot-swap or power sequencing in PLC backplanes. IC Role / Device Role / Timing Role: CD74HC126M acts as a controlled bidirectional buffer enabling/disabling signal flow between master and slave modules using dedicated OE lines. Use Value: Prevents bus contention during module insertion/removal and reduces standby current by placing unused channels in high-Z state. |
Use Scenario: Expanding limited GPIO count of an ARM Cortex-M0+ MCU to drive multiple LED indicators and status relays. IC Role / Device Role / Timing Role: CD74HC126M serves as a level-translating output driver, buffering weak MCU outputs to drive higher-current loads. Use Value: Delivers ±6 mA per channel at 3.3 V, eliminating need for discrete transistors while maintaining fast edge rates (<15 ns transition time). |
| Test Equipment Signal Gating | Automotive Sensor Interface Conditioning |
Use Scenario: Enabling precise timing-controlled injection of test patterns into DUT signal paths during automated functional testing. IC Role / Device Role / Timing Role: CD74HC126M functions as a gated signal repeater, synchronizing pattern delivery with system clock edges via OE timing. Use Value: Propagation delay variation < ±5 ns across temperature ensures deterministic setup/hold margins in high-reliability test fixtures. |
Use Scenario: Buffering analog sensor output signals (e.g., pressure transducer ratiometric outputs) before ADC sampling in engine control units. IC Role / Device Role / Timing Role: CD74HC126M provides clean, isolated digital enable control for sensor excitation circuitry using its 3-state outputs. Use Value: High-impedance off-state prevents loading of precision voltage references during sensor sleep cycles, preserving measurement accuracy. |
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 |
|---|---|---|---|
| SN74HC126N | Same logic function and pinout; PDIP-14 package (19.3 mm × 6.4 mm), higher RθJA (62.2°C/W vs. 133.6°C/W), rated for 0°C to +70°C only | Suitable for lab prototypes or commercial-grade PCBs where wide temperature range is not required | Select SN74HC126N when through-hole assembly or lower thermal resistance is prioritized over extended temperature operation |
| MC74HC126AD | Pin-compatible SOIC-14 variant from ON Semiconductor; identical VCC range and timing specs, but IOZ leakage max = ±20 µA (vs. ±10 µA for CD74HC126M) | Better suited for cost-sensitive consumer electronics where minor leakage increase is acceptable | Choose MC74HC126AD when sourcing flexibility across vendors is needed and tighter 3-state leakage is not critical |
Compared with SN74HC126N and MC74HC126AD, the CD74HC126M offers superior thermal performance in SOIC packaging and the widest operating temperature range (–55°C to +125°C), making it the preferred choice for ruggedized industrial and automotive control applications requiring long-term reliability under thermal stress.
Availability
CD74HC126M is available at Aetrix Electronics and suitable for industrial bus isolation, microcontroller GPIO expansion, test equipment signal gating, and automotive sensor interface conditioning requiring stable component supply across extended temperature ranges.
Supply support for CD74HC126M 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 decades of experience in high-reliability industrial and automotive IC design.
The CD74HC126M belongs to TI's HC logic family, engineered for low-power, wide-voltage-operation digital interfacing in harsh-environment systems where signal integrity and thermal resilience are critical.
FAQ
What is the maximum capacitive load the CD74HC126M can drive while meeting datasheet timing specifications?
The CD74HC126M is characterized for CL = 50 pF in switching specifications, with propagation delay tpd = 25 ns typical at 4.5 V. Driving loads >70 pF may increase delay and transition time beyond guaranteed limits; TI recommends adding a series resistor to limit output current if larger capacitances are unavoidable. The CD74HC126M datasheet explicitly states that optimal performance is ensured at ≤70 pF.
Does the CD74HC126M support mixed-voltage operation-e.g., 3.3 V inputs driving a 5 V-powered CD74HC126M?
Yes-the CD74HC126M accepts input voltages from 0 V to VCC, and its VIH/VIL thresholds scale with supply voltage (e.g., VIH = 1.35 V min at VCC = 4.5 V). A 3.3 V logic HIGH exceeds the VIH threshold of 1.35 V when VCC = 4.5 V, making it fully compatible with mixed-voltage interfaces without external level shifters. This behavior is confirmed in Section 6.3 of the CD74HC126M datasheet.
How should unused inputs and outputs be handled on the CD74HC126M?
Unused inputs must be terminated to VCC or GND-never left floating-to prevent undefined logic states and excessive current draw. Unused outputs may be left unconnected (floating) since the 3-state architecture isolates them when disabled. TI's layout guidelines (Section 11.1) and application note SLLA169 confirm this practice for the CD74HC126M and related HC devices.
Is the CD74HC126M pin-compatible with the older CD74HCT126 series?
No-the CD74HC126M and CD74HCT126 are not pin-compatible due to differing input threshold architectures: HC uses CMOS thresholds (VIH ≈ 0.7×VCC), while HCT uses TTL-compatible thresholds (VIH = 2.0 V fixed). Though both share SOIC-14 packaging and identical pin functions, their input voltage requirements differ fundamentally, making direct substitution unsafe without circuit validation. This distinction is documented in TI's SCHS416 HCT standalone datasheet.
What is the thermal resistance (RθJA) of the CD74HC126M in its SOIC-14 package?
The CD74HC126M in SOIC-14 (D) package has a junction-to-ambient thermal resistance RθJA of 133.6°C/W, as specified in Section 6.4 of the official datasheet. This value assumes standard JEDEC 2-layer board conditions; actual thermal performance improves with PCB copper area and airflow. Designers must ensure power dissipation stays within limits to keep junction temperature below 150°C.
CD74HC126M Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HC
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- 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:
- 7.8mA, 7.8mA
- Voltage - Supply:
- 2V ~ 6V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
CD74HC126M FAQ
1.How can I place an order for CD74HC126M through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HC126M 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 CD74HC126M reliable?
The price and inventory of CD74HC126M are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HC126M is usually 5 days.
3.What payment methods are accepted for CD74HC126M?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HC126M transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for CD74HC126M?
CD74HC126M orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HC126M 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 CD74HC126M?
For technical support, including CD74HC126M datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HC126M requirements.
6.How does Aetrix verify that CD74HC126M is sourced from the original manufacturer or authorized distributors?
All CD74HC126M 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 CD74HC126M meets industry standards.
7.What is the process for return or replacement of CD74HC126M?
All CD74HC126M units undergo pre-shipment inspection (PSI). If there is an issue with CD74HC126M, 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 CD74HC126M part is unused and in its original packaging.
Return procedure for CD74HC126M:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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