SN74HCS126QPWRQ1 - Automotive Quad 3-State Buffer | TI
MPN: SN74HCS126QPWRQ1 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.45 | $0.45 |
| 10 | $0.41 | $4.10 |
| 100 | $0.37 | $37.00 |
| 500 | $0.36 | $180.00 |
| 1,000 | $0.35 | $350.00 |
SN74HCS126QPWRQ1 Overview
A CMOS logic buffer is a digital building block that reproduces (non-inverting) a digital signal while providing isolation between a weak or noisy source and a heavier load. In the logic hierarchy, the SN74HCS126-Q1 belongs to the buffer / line driver family of the HC/HCS CMOS logic category, and bus buffers with 3-state outputs further add the ability to disconnect the output from the bus, enabling shared, multidrop data lines in microprocessor and automotive in-vehicle networking systems.
Key differentiating features include Schmitt-trigger inputs with hysteresis that convert slow or noisy input transitions into clean, fast edges - essential in automotive environments with ground bounce and EMI; 3-state outputs that implement high-impedance bus sharing; low input hysteresis threshold spread across the 2.0 V to 6.0 V operating range; and a typical CMOS microamp-level quiescent current that minimizes system standby power. The device is qualified per AEC-Q100 Grade 1 for harsh automotive ambient temperatures.
Technically, the HCS family combines high-voltage CMOS fabrication with input hysteresis, providing robust switching thresholds (VT+ / VT- spread) across supply voltage, temperature, and process corners. Output drive is balanced across the supply range, and outputs are disabled to high impedance whenever the OE pin is low, allowing multiple drivers on one bus with tri-state control. Power-up and power-down protection prevents bus contention during supply sequencing.
Typical applications include automotive body electronics, CAN/LIN transceiver front-end buffering, level-shifted control signals in 12 V-derived rails, industrial PLC I/O, and generic bus-buffering between microcontrollers and peripheral modules where slow edges must be squared up.
Design tip: do not let the OE pin float - tie unused enables to ground and unused inputs to VCC or GND; ensure each enabled output sources/sinks within the drive limits at the given VCC to keep VOL/VOH within datasheet margins.
This page adds value beyond the manufacturer datasheet by synthesizing distributor pricing, drop-in same-footprint alternatives (HC126 variants, HCS125 siblings), and practical design notes in one place.
Drop-in alternatives for SN74HCS126QPWRQ1 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with SN74HCS126QPWRQ1 (same form factor and footprint) β differing in Input Type, Operating Temperature, Output Type, Package, Qualification.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
SN74HCS125QPWRQ1
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SN74HCS126PWR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SN74HCS125PWR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SN74HC126APWR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SN74HC126PWR
β Drop-In β οΈ εζ°εΎ ιͺθ―π Reference alternative (not in catalog)
SN74HCS126QPWRQ1 Maximum Ratings & Electrical Characteristics
| Logic Function | Quadruple non-inverting buffer with 3-state outputs |
| Input Type | Schmitt-trigger |
| Number of Elements | 4 |
| Bits per Element | 1 |
| Output Type | 3-State, active-high output enable |
| Supply Voltage Range | 2.0 V to 6.0 V |
| Output Enable Polarity | Active-high (OE) |
| Operating Temperature | -40C to +125C (AEC-Q100 Grade 1) |
| Qualification | AEC-Q100 automotive qualified |
| Package | 14-pin TSSOP (PW) |
| Mounting Type | Surface Mount |
| Input Hysteresis | Yes (Schmitt-trigger inputs) |
| RoHS Status | Compliant |
SN74HCS126QPWRQ1 Pin Configuration
| Pin 1 | OE1 β Output enable 1 (active high) |
| Pin 2 | 1A β Data input 1 (Schmitt-trigger) |
| Pin 3 | 1Y β 3-state output 1 |
| Pin 4 | 2OE β Output enable 2 (active high) |
| Pin 5 | 2A β Data input 2 (Schmitt-trigger) |
| Pin 6 | 2Y β 3-state output 2 |
| Pin 7 | GND β Ground |
| Pin 8 | 3Y β 3-state output 3 |
| Pin 9 | 3A β Data input 3 (Schmitt-trigger) |
| Pin 10 | 3OE β Output enable 3 (active high) |
| Pin 11 | 4Y β 3-state output 4 |
| Pin 12 | 4A β Data input 4 (Schmitt-trigger) |
| Pin 13 | 4OE β Output enable 4 (active high) |
| Pin 14 | VCC β Power supply (2.0 V to 6.0 V) |
Typical Applications
SN74HCS126QPWRQ1 is suitable for 6 applications: Automotive Body Electronics, Shared Bus Buffering (MCU to Peripherals), Signal Squaring and Debounce Stages, CAN/LIN Transceiver Front-End Buffering, 3.3 V to 5 V Logic Interface, Industrial PLC and Test Instrumentation I/O.
Automotive Body Electronics
The SN74HCS126QPWRQ1 fits automotive body-control modules, door-zone ECUs, and lighting controllers because it combines AEC-Q100 Grade 1 qualification (-40C to +125C) with Schmitt-trigger inputs that reject the noise and ground bounce pervasive in 12 V automotive electrical systems. Slow, filtered sensor or switch edges arriving from wiring harnesses are squared into fast digital transitions with defined VT+/VT- thresholds across the 2.0 V to 6.0 V supply range. Used as a bus buffer between a microcontroller GPIO bank and shared peripheral buses, its 3-state outputs allow multiple drivers on one line under OE control, while the TSSOP-14 package keeps PCB area small in space-constrained modules.
Recommended
Shared Bus Buffering (MCU to Peripherals)
In multidrop data buses shared by several peripherals, only one driver may assert the line at a time; the SN74HCS126QPWRQ1 provides four independent non-inverting buffers whose active-high OE pins place each output in high impedance when disabled, enabling clean bus arbitration at the board level. The Schmitt-trigger inputs ensure that bus-impaired or RC-filtered edges are re-squared before buffering, preventing metastability and double-clocking downstream. Operating from the same 2.0 V to 6.0 V rail as the MCU I/O bank, the device preserves CMOS logic levels while supplying additional drive capability, and the four channels let one TSSOP-14 package service clock, data, and enable lines of a serial peripheral in a single footprint.
Recommended
Signal Squaring and Debounce Stages
RC-filtered switch inputs, optocoupler outputs, and comparator outputs often present slow edges that violate the rise/fall-time limits of ordinary CMOS gates, causing oscillation and metastability. The Schmitt-trigger inputs of the SN74HCS126QPWRQ1 are purpose-built for this: they convert slow transitions into fast, clean digital edges with fixed hysteresis, so a single device both squares and buffers four signals simultaneously. In industrial control panels and appliance boards, this lets designers add simple RC filtering for EMI robustness without worrying about edge-rate violations. The 2.0 V to 6.0 V supply flexibility matches 3.3 V and 5 V controller domains, and the -40C to +125C range suits outdoor and machine-enclosure environments.
Recommended
CAN/LIN Transceiver Front-End Buffering
Automotive network transceivers for CAN and LIN benefit from clean TX lines and isolated-enable control; the SN74HCS126QPWRQ1 buffers MCU TX signals toward the transceiver while the 3-state OE pins allow the controller to tri-state the driver during fault handling or sleep states. Its Grade 1 temperature rating and AEC-Q100 qualification align with in-vehicle network module requirements, and Schmitt inputs square up wake-up and supervisory signals arriving with slow edges from RC filter networks used for LIN wake detection. The low CMOS quiescent current keeps module standby drain within automotive targets, and the 14-pin TSSOP minimizes PCB area beside the transceiver in gateway and body-controller nodes.
Recommended
3.3 V to 5 V Logic Interface
Mixed-voltage boards frequently need to pass logic signals between 3.3 V microcontrollers and 5 V legacy peripherals or 5 V-referenced actuators. Powered from the 5 V rail, the SN74HCS126QPWRQ1 buffers 3.3 V logic into 5 V CMOS levels: its Schmitt-trigger thresholds across the 2.0 V to 6.0 V range accept 3.3 V outputs reliably while the outputs swing full-rail at 5 V, giving improved noise margins to the receiving side. The 3-state outputs additionally implement one-way gating controlled by the MCU. This approach avoids dedicated level translators where unidirectional buffering is sufficient, and the AEC-Q100 rating extends the technique into automotive mixed-domain designs where simple, robust buffering beats complex translation ICs.
Recommended
Industrial PLC and Test Instrumentation I/O
Programmable logic controllers and bench instrumentation route noisy field and sensor signals through digital conditioning stages; the SN74HCS126QPWRQ1 squares these signals with Schmitt-trigger hysteresis and buffers them onto internal buses using its 3-state outputs, so a shared processor bus can read multiple channels without contention. Its 2.0 V to 6.0 V operation supports 3.3 V, 5 V, and mixed I/O backplanes, while the wide -40C to +125C operating range, though automotive qualified, equally serves industrial cabinets exposed to heat from power electronics. The TSSOP-14 surface-mount package supports automated assembly and rework, and low quiescent current simplifies power budgeting across the many logic devices typical of I/O conditioning boards.
Recommended
Recommended Products Summary
Engineering reference data for SN74HCS126QPWRQ1 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SN74HCS125QPWRQ1 | SN74HCS126PWR | SN74HC126APWR | SN74HC126PWR |
|---|---|---|---|---|---|
| Package | 14-pin TSSOP (PW) | 14-pin TSSOP (PW) - same | 14-pin TSSOP (PW) - same | 14-pin TSSOP (PW) - same | 14-pin TSSOP (PW) - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Input Type | Schmitt-trigger | Schmitt-trigger | Schmitt-trigger | Standard CMOS (no hysteresis) | Standard CMOS (no hysteresis) |
| Output Enable Polarity | Active-high (OE) | Active-low (OE-bar) | Active-high (OE) | Active-high (OE) | Active-high (OE) |
| Supply Voltage Range | 2.0 V to 6.0 V | 2.0 V to 6.0 V | 2.0 V to 6.0 V | 2.0 V to 6.0 V | 2.0 V to 6.0 V |
| Automotive Qualification | AEC-Q100 Grade 1 | AEC-Q100 Grade 1 | Not automotive qualified | Not automotive qualified | Not automotive qualified |
Key Differentiators
- Schmitt-trigger inputs for noisy/slow edges (vs SN74HC126APWR)
- AEC-Q100 Grade 1 automotive qualification (vs SN74HCS126PWR)
- Active-high output enables (vs SN74HCS125QPWRQ1)
Design Notes
Decouple each SN74HCS126QPWRQ1 supply pin with a 100 nF ceramic capacitor placed within 5 mm of pin 14 (VCC) to pin 7 (GND), plus one bulk 1 uF per logic bank. CMOS outputs switching four channels simultaneously can draw high transient currents; short, direct ground return paths under the TSSOP-14 minimize ground bounce, which would otherwise appear at the Schmitt thresholds and degrade noise immunity.
Never leave the four OE pins (1, 4, 10, 13) floating - an undefined enable state can cause bus contention or stuck-high-impedance outputs. Tie unused OE pins to GND and tie unused A inputs to VCC or GND per standard CMOS practice to prevent floating-input oscillation and excess supply current. Confirm the active-high OE polarity before dropping in from a '125-style (active-low) design, as the enable polarity is the key difference between the two siblings.
The Schmitt-trigger inputs allow RC filtering on input lines for EMI robustness - typical automotive practice is a 10 kOhm series resistor with 1-10 nF to ground, forming edges well below the hysteresis band. When driving long harness lines, add 33-100 Ohm series resistors at the 3-state outputs to damp reflections, and ensure bus turn-around timing accounts for the enable/disable delays specified in the TI datasheet so two drivers never overlap on a shared line.
Compliance Information
AEC-Q100 Grade 1 automotive qualification confirmed by the Q1 suffix and TI product page. RoHS/lead-free per TI ordering and quality information; REACH and halogen-free declarations not stated in provided data.
