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Texas Instruments SN74AHC126BQAR
- Part No.:
- SN74AHC126BQAR
- Manufacturer:
- Texas Instruments
- Package:
- 14-WFQFN Exposed Pad
- Datasheet:
-
SN74AHC126BQAR.pdf
- Description:
- 4-CH, 2-V TO 5.5-V BUFFERS WITH
- Quantity:
- Payment:
- Shipping:
Inventory:3,000
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Product details
Overview
SN74AHC126BQAR from Texas Instruments is a quadruple bus buffer gate with independent 3-state outputs, designed for digital signal routing and bus isolation in 2V–5.5V systems. It delivers 3.8 ns typical propagation delay at 5 V, supports ±25 mA output drive, and features balanced CMOS outputs for bidirectional current handling - used in logic-level translation and transmission line driving.
For engineers reviewing the SN74AHC126BQAR datasheet, SN74AHC126BQAR pinout, SN74AHC126BQAR application, or SN74AHC126BQAR equivalent, this page provides verified functional modes, thermal metrics for WQFN-14, latch-up immunity (>250 mA), and precise switching characteristics across 3.3 V and 5 V supply rails.
Technical Context
The SN74AHC126BQAR implements four independent non-inverting buffers (Y = A), each controlled by a dedicated output-enable (OE) input. Its 3-state outputs support high-impedance disconnection during power sequencing or bus sharing, with pull-down resistor guidance for OE during power-up.
It uses standard CMOS inputs with ≤10 pF input capacitance and supports rail-to-rail logic thresholds (VIH = 3.85 V @ VCC = 5.5 V, VIL = 1.65 V @ VCC = 5.5 V). The device includes clamp diodes on all I/O pins and meets JESD 17 latch-up requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 5.5 V - enables interoperability across 2.5 V, 3.3 V, and 5 V logic domains without level shifters. |
| tPLH / tPHL (5 V) | 3.8 ns typical - ensures sub-4 ns timing margin for high-speed control signals in FPGA/CPU interface buses. |
| IOH / IOL | ±8 mA @ 5 V - sufficient to directly drive LEDs, small capacitive loads (<50 pF), or multiple 74AHC inputs. |
| II Input Leakage | ±1 μA max - guarantees stable logic states with high-impedance biasing (e.g., 10 kΩ pull-ups/downs). |
| ESD Rating (HBM) | ±2000 V - meets industrial handling requirements without additional protection circuitry. |
| Operating Temp | –40°C to +125°C - qualified for extended-temperature industrial and automotive under-hood applications. |
| Package | WQFN-14 (BQA), 3 mm × 2.5 mm - compact footprint with thermal pad for improved power dissipation in dense PCB layouts. |
Pinout & Package
SN74AHC126BQAR is housed in a 14-pin WQFN (BQA) package with an exposed thermal pad. The package measures 3 mm × 2.5 mm (body size), has a 0.5 mm pitch, and requires Level-1 moisture sensitivity handling (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE, 3OE, 4OE | Dedicated output-enable inputs | Active-low control per channel; allows independent 3-state management of each buffer without shared enable logic. |
| 1A–4A | Buffer input terminals | CMOS-compatible inputs accepting 0–VCC voltage range; must be tied to VCC or GND if unused. |
| 1Y–4Y | Buffer output terminals | 3-state outputs with balanced sourcing/sinking; high-impedance state prevents bus contention during disable. |
| VCC (Pin 14) | Positive supply | Single-supply operation; decoupling capacitor (0.1 μF) required within 3 mm of pin for noise suppression. |
| GND (Pin 7) | Ground reference | Common return path for all channels; thermal pad (underside) must be soldered to PCB ground plane for thermal performance. |
Key Features
| Feature | Design Value |
|---|---|
| Quadruple independent buffers | Four isolated Y = A functions enable selective signal gating without cross-talk or shared timing paths. |
| Balanced 3-state outputs | ±25 mA drive capability in both HIGH and LOW states ensures matched rise/fall times and reduced signal skew. |
| Low propagation delay | 3.8 ns typical at 5 V allows use in >100 MHz clock distribution or fast control loops with tight setup/hold margins. |
| Latch-up immunity | Exceeds 250 mA per JESD 17 - eliminates risk of destructive latch-up in noisy industrial environments. |
| Wide supply range | 2 V–5.5 V operation supports mixed-voltage systems and brown-out tolerant designs without external regulators. |
Applications
| LED Indicator Control | Transmission Line Driver |
|---|---|
|
Use Scenario: Driving multi-color status LEDs on industrial HMI panels with shared microcontroller GPIOs. IC Role / Device Role / Timing Role: Signal buffer and current amplifier; isolates MCU pins from LED forward voltage drops and surge currents. Use Value: Eliminates need for discrete transistors or current-limiting resistors per LED, reducing BOM count and layout area. |
Use Scenario: Driving 50 Ω coaxial or PCB trace transmission lines between FPGA and ADC in test equipment. IC Role / Device Role / Timing Role: Digital signal repeater with controlled edge rates; matches impedance to minimize reflections. Use Value: Maintains signal integrity up to 100 Mbps with <1 ns skew between channels, avoiding eye diagram closure. |
| Bus Isolation Switch | Logic-Level Translation |
|
Use Scenario: Enabling/disabling communication between two I²C master devices sharing a common slave bus. IC Role / Device Role / Timing Role: Bidirectional bus gate; 3-state outputs prevent contention when either master asserts SDA/SCL. Use Value: Prevents data corruption during hot-plug events or firmware resets without requiring arbitration logic. |
Use Scenario: Interfacing a 3.3 V microcontroller GPIO to a 5 V sensor interface IC with TTL-compatible inputs. IC Role / Device Role / Timing Role: Unidirectional level shifter; translates logic HIGH/LOW thresholds across VCC domains. Use Value: Achieves safe 3.3 V → 5 V translation without external resistors or direction control signals. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus buffer applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LVC126AQPWRQ1 | Automotive-qualified (AEC-Q100), 1.65 V–5.5 V VCC, slightly higher ICC (max 10 μA vs. 4 μA) | Required for automotive infotainment or ADAS modules needing zero-defect reliability certification | Choose for automotive production; not drop-in due to different qualification scope and test flow |
| 74AHC126PW,118 | TSSOP-14 package (5 mm × 6.4 mm), same electrical specs, no thermal pad, RθJA = 147.7°C/W vs. 124.6°C/W | Suitable for prototyping or low-power applications where thermal performance is less critical | Choose for legacy board compatibility or manual assembly; larger footprint but easier rework |
Compared with SN74AHC126BQAR, the SN74LVC126AQPWRQ1 adds automotive qualification at the cost of higher static current, while the 74AHC126PW,118 trades thermal efficiency for mechanical simplicity - both require layout review for pin mapping and thermal relief.
Availability
SN74AHC126BQAR is available at Aetrix Electronics and suitable for industrial automation interfaces, embedded sensor hubs, and programmable logic peripheral expansion requiring stable component supply across extended temperature ranges.
Supply support for SN74AHC126BQAR 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.
The SN74AHC126BQAR belongs to TI's advanced high-speed CMOS logic family, engineered for low-power, high-noise-immunity digital interfacing in space-constrained and thermally demanding applications.
FAQ
What is the maximum output current rating for SN74AHC126BQAR?
The SN74AHC126BQAR supports ±25 mA continuous output current per channel, verified across –40°C to +125°C. This rating applies to both sourcing (IOH) and sinking (IOL) modes at VCC = 5 V, enabling direct drive of LEDs or small capacitive loads without external amplification. Exceeding this limit risks thermal shutdown or permanent damage per Absolute Maximum Ratings.
Does SN74AHC126BQAR support mixed-voltage operation between input and output sides?
No - SN74AHC126BQAR is a single-supply device with all I/O referenced to the same VCC pin. Inputs accept 0–VCC voltage range, and outputs swing rail-to-rail within that supply. For true level translation (e.g., 3.3 V input → 5 V output), a dual-supply translator like TXB0104 is required. SN74AHC126BQAR operates correctly only when VCC defines the entire logic domain.
How should unused inputs be handled on SN74AHC126BQAR?
All unused inputs on SN74AHC126BQAR must be terminated to either VCC or GND using a 10 kΩ resistor - floating CMOS inputs cause excessive power consumption and potential oscillation. This requirement applies to all A and OE pins not in active use. Leaving them unconnected violates Recommended Operating Conditions and may degrade noise immunity or cause erratic output behavior.
What is the purpose of the thermal pad on the SN74AHC126BQAR (BQA) package?
The exposed thermal pad on SN74AHC126BQAR serves as the primary heat dissipation path from the die to the PCB. It must be soldered to a solid copper ground plane to achieve the specified RθJB = 81.2°C/W. Leaving it unconnected or floating increases junction temperature by >20°C under full load, risking derating or premature failure. Thermal vias beneath the pad are recommended for high-reliability designs.
Can SN74AHC126BQAR be used in place of SN74AHC125?
No - SN74AHC126BQAR contains four non-inverting buffers (Y = A), whereas SN74AHC125 contains four inverting buffers (Y = NOT A). Their logic functions are complementary and not interchangeable without redesigning upstream/downstream logic. Pinouts are identical, but substituting one for the other will invert all signal paths, causing system-level functional failure unless compensated in firmware or external logic.
SN74AHC126BQAR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHC
- Package/Case:
- 14-WFQFN Exposed Pad
- 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:
- 8mA, 8mA
- Voltage - Supply:
- 2V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-WQFN (3x2.5)
SN74AHC126BQAR FAQ
1.How can I place an order for SN74AHC126BQAR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHC126BQAR 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 SN74AHC126BQAR reliable?
The price and inventory of SN74AHC126BQAR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHC126BQAR is usually 5 days.
3.What payment methods are accepted for SN74AHC126BQAR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHC126BQAR transactions.
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4.How is shipping managed for SN74AHC126BQAR?
SN74AHC126BQAR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHC126BQAR 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 SN74AHC126BQAR?
For technical support, including SN74AHC126BQAR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHC126BQAR requirements.
6.How does Aetrix verify that SN74AHC126BQAR is sourced from the original manufacturer or authorized distributors?
All SN74AHC126BQAR 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 SN74AHC126BQAR meets industry standards.
7.What is the process for return or replacement of SN74AHC126BQAR?
All SN74AHC126BQAR units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHC126BQAR, 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 SN74AHC126BQAR part is unused and in its original packaging.
Return procedure for SN74AHC126BQAR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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