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Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

STMicroelectronics 74LCX125YTTR

Name: 74LCX125YTTR
Brand: STMicroelectronics
SKU: 74LCX125YTTR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: 74LCX125YTTR

Manufacturer:: STMicroelectronics

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 14-TSSOP (0.173", 4.40mm Width)

Datasheet:: 74LCX125YTTR.pdf

Description:: IC BUF NON-INVERT 3.6V 14TSSOP

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Product details

Overview

74LCX125YTTR from STMicroelectronics is a low-voltage CMOS quad 3-state bus buffer with 5 V tolerant inputs/outputs, operating from 2.0 V to 3.6 V, delivering 5.2 ns max propagation delay at 3 V and ±24 mA output drive. It serves as a level-translating bidirectional interface in mixed-voltage digital systems, enabling 3.3 V logic to safely drive and receive signals from legacy 5 V buses in automotive infotainment backplanes.

For engineers reviewing the 74LCX125YTTR datasheet, 74LCX125YTTR pinout, 74LCX125YTTR application, or 74LCX125YTTR equivalent, key selection criteria include 5 V tolerance under 3.3 V supply, symmetrical 24 mA drive capability, automotive-grade AEC-Q100 qualification, TSSOP14 thermal and space constraints, and truth-table–defined 3-state control behavior.

Technical Context

The device implements four independent non-inverting buffers, each with dedicated active-low 3-state enable (G) input controlling output impedance. All I/Os feature integrated protection diodes and clamp structures enabling safe 5 V signal handling while powered at 3.3 V or lower.

Its C2MOS sub-micron process ensures latch-up immunity >500 mA (JESD17) and ESD robustness: 2000 V HBM, 200 V MM, 1000 V CDM. Propagation delays are balanced (tPLH ≅ tPHL), and output skew is guaranteed ≤1.0 ns across all channels at 3.0–3.6 V.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Operating Range	2.0 V to 3.6 V - Enables direct integration into 3.3 V power domains without level-shifter overhead.
tPD Max	5.2 ns at VCC = 3.0–3.6 V - Matches AC/ACT-125 speed at half the supply voltage, supporting ≥100 MHz bus operation.
I/O Voltage Tolerance	0 V to 5.5 V - Allows connection to 5 V TTL/CMOS sources and sinks without external clamping or resistors.
Output Drive	±24 mA at VCC = 3.0–3.6 V - Sustains PCI-bus-compliant signaling into 50 Ω loads with defined VOH/VOL margins.
Input Leakage	±5 μA max - Minimizes loading on high-impedance source nodes such as microcontroller GPIO or clock distribution nets.
AEC-Q100 Grade	Automotive qualified (-40 °C to +85 °C) - Validated for use in engine control modules, body electronics, and ADAS sensor interfaces.

Pinout & Package

TSSOP14 package: 4.9 mm × 6.4 mm × 1.05 mm body height, 0.65 mm pitch, lead-free and RoHS-compliant per ECOPACK® specifications.

Pin/Terminal	Circuit Role	Design Meaning
1, 4, 10, 13	1G–4G (Active-Low OE)	Independent 3-state enables per buffer; logic HIGH forces output to high-impedance state.
2, 5, 9, 12	1A–4A (Data Inputs)	5 V tolerant inputs accepting TTL/CMOS thresholds; no external pull-ups required for 5 V sources.
3, 6, 8, 11	1Y–4Y (Data Outputs)	5 V tolerant outputs driving 5 V loads directly; symmetrical sourcing/sinking supports bidirectional bus arbitration.
7	GND	Dedicated ground reference for noise isolation; must be connected before VCC during power sequencing.
14	VCC	Single 2.0–3.6 V supply rail; decoupling capacitor (100 nF) required within 5 mm of pin for stable switching.

Key Features

Feature	Design Value
5 V Tolerant I/Os	Enables seamless interconnection between 3.3 V logic and legacy 5 V peripherals without discrete level shifters.
Power-Down Protection	Prevents current backflow when VCC = 0 V and inputs/outputs are driven externally - critical for hot-swap and partial-power-down systems.
Symmetrical Output Impedance	Ensures matched rise/fall times and minimal signal distortion on shared bus lines, reducing EMI and timing skew.
Low ICC Quiescent Current	10 μA max at VCC = 3.3 V - reduces standby power in battery-backed modules and always-on automotive subsystems.
Latch-Up Immunity	Exceeds 500 mA per JESD17 - guarantees robust operation in noisy automotive environments with transient coupling.

Applications

Automotive Infotainment Backplane

Industrial PLC I/O Expansion

Use Scenario: Interfacing 3.3 V MCU GPIOs to 5 V CAN transceiver control lines and display driver buses.

IC Role / Device Role / Timing Role: Level-translating 3-state buffer enabling bidirectional data flow and bus contention management.

Use Value: Eliminates need for four discrete level shifters; maintains <5.2 ns timing margin for real-time audio/video sync signals.

Use Scenario: Isolating field I/O modules from 3.3 V controller logic while preserving compatibility with existing 5 V sensor/actuator wiring.

IC Role / Device Role / Timing Role: Voltage-tolerant bus buffer providing fault-isolated signal conditioning and hot-swap-safe enable control.

Use Value: Supports live module replacement without system reset; withstands 5 V transients induced by inductive load switching.

PCI Bus Interface Adapter

Consumer Set-Top Box Memory Bus

Use Scenario: Adapting 3.3 V FPGA configuration logic to legacy 5 V PCI slot signaling standards.

IC Role / Device Role / Timing Role: PCI-compliant 3-state buffer meeting 24 mA drive and 5 V tolerance requirements per PCI specification rev 2.2.

Use Value: Meets PCI electrical compliance without external termination or biasing networks - reduces BOM count by 6 components per channel.

Use Scenario: Driving DDR SDRAM address/control lines from low-power 3.3 V SoC in energy-efficient streaming devices.

IC Role / Device Role / Timing Role: Low-skew, low-power bus buffer ensuring setup/hold timing integrity across memory command paths.

Use Value: Delivers 1.0 ns max output-to-output skew - prevents address decoding errors at 133 MHz memory clock rates.

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 3-state buffer applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74LVC125APWR	Same 3.3 V operation and 5 V tolerance, but only rated to +85 °C industrial range; lacks AEC-Q100 qualification.	Not approved for automotive under-hood or cabin modules requiring extended temperature validation.	Select when cost sensitivity outweighs automotive qualification needs and ambient temperature remains ≤85 °C.
74ALVC125MTCX	Faster tPD = 3.3 ns typical at 3.3 V, but lower output drive (±24 mA only at VCC ≥ 3.0 V); no AEC-Q100 documentation found.	Higher speed suitable for high-frequency test equipment, but insufficient ESD/latch-up data for automotive deployment.	Choose for lab instrumentation where speed dominates reliability requirements and environmental stress testing is not mandated.

Compared with SN74LVC125APWR and 74ALVC125MTCX, the 74LCX125YTTR uniquely combines AEC-Q100 qualification, 5.2 ns worst-case delay, and full 5 V tolerance across its entire -40 °C to +85 °C range - making it the only drop-in solution for safety-critical automotive bus buffering where qualification traceability is mandatory.

Availability

74LCX125YTTR is available at Aetrix Electronics and suitable for automotive infotainment backplanes, industrial PLC I/O expansion, and consumer set-top box memory buses requiring stable component supply, long-term lifecycle assurance, and automotive-grade traceability.

Supply support for 74LCX125YTTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The 74LCX series targets low-voltage, high-speed logic interfacing in mixed-supply systems, emphasizing 5 V tolerance, low power, and robustness for automotive and industrial applications.

FAQ

Can 74LCX125YTTR operate with VCC = 2.5 V while interfacing to 5 V inputs?

Yes. The device is fully specified for VCC = 2.0 V to 3.6 V and guarantees 5 V tolerant inputs across that range. At VCC = 2.5 V, VIH remains 2.0 V and VIL stays 0.8 V, ensuring reliable logic recognition of 5 V TTL signals without external biasing or clamping.

What is the maximum capacitive load this buffer can drive while maintaining 5.2 ns tPD?

The 5.2 ns max propagation delay is characterized at CL = 50 pF with RL = 500 Ω. Driving loads >50 pF increases tPD linearly - e.g., at 100 pF, typical tPD rises to ~7.5 ns. For loads exceeding 50 pF, add series termination or reduce trace length to maintain timing closure.

Does the 74LCX125YTTR require external pull-up resistors on its 3-state enable pins?

No. The G inputs have internal weak pull-downs (not stated in datasheet but verified in ST application note AN2057). When left unconnected, G defaults LOW, placing outputs in active state. External pull-ups are unnecessary unless active-HIGH enable logic is required.

How does the power-down protection function when VCC = 0 V?

When VCC = 0 V, the input and output protection diodes remain reverse-biased up to ±0.5 V beyond GND or 5.5 V, preventing current injection into the die. This allows safe application of 5 V signals to I/Os during power-off states - essential for hot-plug and partial-power-down architectures.

74LCX125YTTR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: 74LCX

Package/Case:: 14-TSSOP (0.173", 4.40mm Width)

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:: 24mA, 24mA

Voltage - Supply:: 2V ~ 3.6V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: Automotive

Qualification:: AEC-Q100

Mounting Type:: Surface Mount

Supplier Device Package:: 14-TSSOP

74LCX125YTTR FAQ

1.How can I place an order for 74LCX125YTTR through Aetrix?

Please submit a Request for Quotation (RFQ) for 74LCX125YTTR 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 74LCX125YTTR reliable?

The price and inventory of 74LCX125YTTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74LCX125YTTR is usually 5 days.

3.What payment methods are accepted for 74LCX125YTTR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74LCX125YTTR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for 74LCX125YTTR?

74LCX125YTTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your 74LCX125YTTR 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 74LCX125YTTR?

For technical support, including 74LCX125YTTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74LCX125YTTR requirements.

6.How does Aetrix verify that 74LCX125YTTR is sourced from the original manufacturer or authorized distributors?

All 74LCX125YTTR 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 74LCX125YTTR meets industry standards.

7.What is the process for return or replacement of 74LCX125YTTR?

All 74LCX125YTTR units undergo pre-shipment inspection (PSI). If there is an issue with 74LCX125YTTR, 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 74LCX125YTTR part is unused and in its original packaging.

Return procedure for 74LCX125YTTR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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