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Texas Instruments CD74HCT126MG4
- Part No.:
- CD74HCT126MG4
- Manufacturer:
- Texas Instruments
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
CD74HCT126MG4.pdf
- Description:
- IC BUF NON-INVERT 5.5V 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,263
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Product details
Overview
CD74HCT126MG4 from Texas Instruments is a quadruple non-inverting buffer with 3-state outputs, designed for bus interface and signal routing in digital systems. It operates across 4.5 V to 5.5 V supply voltage, supports –55°C to +125°C temperature range, delivers propagation delay of 17–21 ns at 6 V (CL = 15 pF), and drives up to 10 LSTTL loads. It enables bidirectional data bus control in industrial control modules.
For engineers reviewing the CD74HCT126MG4 datasheet, CD74HCT126MG4 pinout, CD74HCT126MG4 application, or CD74HCT126MG4 equivalent, key selection criteria include 3-state output timing consistency, TTL-compatible input thresholds, SOIC-14 thermal performance (RθJA = 133.6°C/W), and guaranteed operation over extended temperature range without derating.
Technical Context
This device implements four independent positive-logic buffers (Y = A) with active-low 3-state enable inputs (OE). Each channel features balanced CMOS outputs capable of sourcing/sinking ±7.8 mA at 6 V while maintaining VOH ≥ 5.48 V and VOL ≤ 0.4 V under load.
It uses standard CMOS inputs with VIH = 3.15 V (min) and VIL = 1.35 V (max) at VCC = 4.5 V, ensuring compatibility with TTL logic families. The 3-state control architecture allows precise bus contention avoidance during power-down or multi-master arbitration sequences.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures direct compatibility with 5-V TTL and mixed-voltage system rails without level shifting. |
| Propagation Delay | 17–21 ns at 6 V, CL = 15 pF - Enables reliable timing in 25-MHz+ synchronous bus interfaces. |
| Output Drive | ±7.8 mA at 6 V - Sustains full logic swing into 50-Ω transmission lines or fanout of 10 LSTTL loads. |
| Operating Temperature | –55°C to +125°C - Qualified for under-hood automotive, military, and industrial embedded environments. |
| Input Thresholds | VIH = 3.15 V, VIL = 1.35 V at VCC = 4.5 V - Guarantees robust noise margin (>0.8 V) against TTL-level signals. |
| 3-State Leakage | ±5 µA max at 6 V - Prevents unintended bus loading during high-impedance state in multiplexed architectures. |
Pinout & Package
CD74HCT126MG4 is housed in a 14-pin SOIC (D) package measuring 8.70 mm × 3.90 mm with gull-wing leads and RoHS-compliant NiPdAu finish. It has a moisture sensitivity level (MSL) rating of Level-1 (unlimited floor life at ≤30°C/60% RH).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 4OE, 3OE, 2OE | Active-low output enable | Controls 3-state mode per channel; low = enabled output, high = high-Z - enables independent bus segment gating. |
| 1A, 2A, 3A, 4A | Buffer input | CMOS-compatible input accepting TTL-level signals; must be terminated to VCC or GND if unused. |
| 1Y, 2Y, 3Y, 4Y | Buffer output | 3-state CMOS output with balanced drive; floats when OE high - prevents bus contention during disable. |
| VCC (Pin 14) | Positive supply | 4.5–5.5 V 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 |
|---|---|
| TTL-compatible inputs | VIH/VIL thresholds match legacy 5-V TTL logic, eliminating need for external level translators in mixed-technology designs. |
| Balanced 3-state outputs | Sources and sinks equal current (±7.8 mA), enabling clean bus release and preventing latch-up during hot-swap transitions. |
| Extended temperature operation | Rated from –55°C to +125°C - supports deployment in engine control units, avionics, and downhole instrumentation. |
| Low dynamic power | ICC = 80 µA max at 6 V - reduces quiescent power in always-on monitoring subsystems without sacrificing speed. |
| Clamp diode protection | Integrated input/output ESD diodes rated for ±2000-V HBM - enhances reliability in handling-sensitive manufacturing and field service environments. |
Applications
| Industrial Bus Interface | Automotive Sensor Hub |
|---|---|
Use Scenario: Isolating microcontroller GPIOs from noisy 24-V PLC backplane signals using level-shifted control lines. IC Role / Device Role / Timing Role: Bidirectional buffer enabling/disabling data flow between isolated CAN controller and analog sensor ADC chain. Use Value: Prevents bus contention during MCU reset by placing outputs in high-Z state; maintains signal integrity with <21 ns propagation delay. | Use Scenario: Multiplexing temperature, pressure, and position sensor outputs onto shared diagnostic bus in ADAS domain controller. IC Role / Device Role / Timing Role: 3-state gate managing time-division access to serial sensor interface, synchronized to master clock edge. Use Value: Eliminates need for discrete MOSFET switches; supports –40°C cold-cranking and +105°C under-hood operation. |
| Military Data Acquisition | Test Equipment Signal Routing |
Use Scenario: Enabling analog front-end sampling paths in ruggedized field-deployable spectrum analyzers. IC Role / Device Role / Timing Role: Channel-select buffer isolating ADC input from FPGA-based digital processing block during calibration cycles. Use Value: Guaranteed operation at –55°C ensures startup reliability in arctic deployments; ±7.8 mA drive handles long PCB traces. | Use Scenario: Reconfigurable signal path switching in automated test equipment (ATE) mainframe backplane. IC Role / Device Role / Timing Role: Logic-level translator and bus driver routing DUT signals between multiple instrument modules. Use Value: Pin-compatible replacement for obsolete 74LS126; eliminates redesign while supporting higher-speed test patterns. |
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 |
|---|---|---|---|
| SN74HCT125DR | Quad buffer with active-high OE (vs. active-low OE on CD74HCT126MG4); identical timing, drive, and voltage specs. | Requires inverted enable logic in existing schematics; no change to bus timing or thermal design. | Select when system-level enable signals are active-high and board layout cannot accommodate inverters. |
| 74AC126M | Wider VCC range (2–6 V) but higher ICC (160 µA max); same pinout and 3-state behavior; AC family offers faster tpd (10 ns @ 5 V). | Not qualified for –55°C operation; unsuitable for military or extended-temperature industrial use. | Choose for cost-sensitive commercial applications requiring sub-15 ns delay and 3.3-V compatibility. |
Compared with SN74HCT125DR and 74AC126M, CD74HCT126MG4 provides guaranteed –55°C operation and active-low enable polarity optimized for legacy bus arbitration schemes, while maintaining identical SOIC-14 footprint and thermal profile.
Availability
CD74HCT126MG4 is available at Aetrix Electronics and suitable for industrial bus interface, automotive sensor hub, military data acquisition, and test equipment signal routing requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for CD74HCT126MG4 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 delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
CD74HCT126MG4 belongs to TI's HCT logic family, engineered specifically for TTL-to-CMOS interfacing in harsh-environment systems where reliability, temperature resilience, and pin compatibility with legacy 74-series logic are critical.
FAQ
What is the maximum operating supply voltage for CD74HCT126MG4?
The absolute maximum supply voltage for CD74HCT126MG4 is 7 V, but the recommended operating range is strictly 4.5 V to 5.5 V. Operation outside this range may cause timing violations or increased ICC, and TI specifies electrical characteristics only within 4.5–5.5 V. Exceeding 5.5 V risks violating the VOH/VOL specifications and accelerating electromigration in the SOIC package.
Does CD74HCT126MG4 support true bidirectional data flow?
No, CD74HCT126MG4 is a unidirectional buffer (Y = A) with 3-state outputs - it does not auto-detect direction or contain internal transceivers. Bidirectional operation requires external control logic to coordinate OE signals across paired devices or use of dedicated transceiver ICs like SN74LVC8T245. Each channel of CD74HCT126MG4 routes signal in one fixed direction only.
Can CD74HCT126MG4 drive a 50-Ω transmission line directly?
Yes, CD74HCT126MG4 can drive a 50-Ω line when loaded with ≤70 pF total capacitance, as verified in TI's application curves. At 6 V, its ±7.8 mA output drive sustains VOH ≥ 5.48 V and VOL ≤ 0.4 V into 50 Ω, though signal integrity requires series termination or controlled-impedance PCB routing to suppress reflections. TI recommends limiting trace length to ≤10 cm for clean edges.
What is the thermal resistance (RθJA) of CD74HCT126MG4 in SOIC-14 package?
The junction-to-ambient thermal resistance (RθJA) for CD74HCT126MG4 in SOIC-14 (D) package is 133.6°C/W, per TI's SCHS144D datasheet revision June 2021. This value assumes standard JEDEC 2-layer board conditions; actual thermal performance improves with internal copper planes or thermal vias. Maximum power dissipation at 125°C ambient is ~375 mW before exceeding TJ(max) = 150°C.
How should unused inputs and outputs be handled on CD74HCT126MG4?
Unused inputs on CD74HCT126MG4 must be tied to VCC or GND - floating inputs cause excessive ICC and potential oscillation due to CMOS threshold ambiguity. Unused outputs may be left floating, as the 3-state leakage (IOZ ≤ ±5 µA) poses no risk. TI's layout guide explicitly shows unused inputs terminated to VCC and outputs left unconnected in Figure 11-1.
CD74HCT126MG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- 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:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -55°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
CD74HCT126MG4 FAQ
1.How can I place an order for CD74HCT126MG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for CD74HCT126MG4 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 CD74HCT126MG4 reliable?
The price and inventory of CD74HCT126MG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for CD74HCT126MG4 is usually 5 days.
3.What payment methods are accepted for CD74HCT126MG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for CD74HCT126MG4 transactions.
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4.How is shipping managed for CD74HCT126MG4?
CD74HCT126MG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your CD74HCT126MG4 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 CD74HCT126MG4?
For technical support, including CD74HCT126MG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your CD74HCT126MG4 requirements.
6.How does Aetrix verify that CD74HCT126MG4 is sourced from the original manufacturer or authorized distributors?
All CD74HCT126MG4 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 CD74HCT126MG4 meets industry standards.
7.What is the process for return or replacement of CD74HCT126MG4?
All CD74HCT126MG4 units undergo pre-shipment inspection (PSI). If there is an issue with CD74HCT126MG4, 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 CD74HCT126MG4 part is unused and in its original packaging.
Return procedure for CD74HCT126MG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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