Texas Instruments SN74AC240QPWRQ1

Overview

SN74AC240QPWRQ1 from Texas Instruments is an automotive-grade octal inverting buffer/driver with dual 3-state outputs, operating from 2V to 6V V_CC, supporting input voltages up to 6V, delivering max propagation delay of 6.5ns at 5V, and rated for −40°C to +125°C ambient temperature - used in automotive body control modules for signal redriving and bus isolation.

For engineers reviewing the SN74AC240QPWRQ1 datasheet, SN74AC240QPWRQ1 pinout, SN74AC240QPWRQ1 application, or SN74AC240QPWRQ1 equivalent, key selection criteria include automotive AEC-Q100 qualification, dual independent 3-state enable control (1OE/2OE), rail-to-rail input tolerance, guaranteed t_PLH/t_PHL ≤ 6.5ns at 5V, and TSSOP-20 package compatibility with high-density PCB layouts.

Technical Context

The SN74AC240QPWRQ1 implements two independent 4-bit inverting buffer sections, each with dedicated output-enable inputs (1OE and 2OE), enabling selective 3-state control of Y1–Y4 outputs per section. Its AC logic family delivers improved noise immunity over standard TTL while maintaining CMOS power efficiency.

Each buffer stage provides true inversion (A → Y), supports hot-swap tolerant inputs (VI up to 6V regardless of V_CC), and guarantees high-impedance outputs when OE is high - critical for bidirectional bus arbitration and transmission line driving without contention.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.5mm × 6.4mm footprint, 1.2mm max height, 0.65mm lead pitch, exposed thermal pad not present - compatible with standard SMT reflow profiles (MSL Level-1).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal inverting buffer applications.

Compared with SN74LVC240APWR and MC74VHC240DT, the SN74AC240QPWRQ1 uniquely combines AEC-Q100 Grade 1 qualification, 6.5ns speed at 5V, and 6V input tolerance - making it the only option for timing-constrained, safety-rated automotive signal conditioning where rail flexibility and certification are mandatory.

Availability

SN74AC240QPWRQ1 is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor interfaces, and redundant communication node designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74AC240QPWRQ1 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 automotive ICs, with decades of experience in high-reliability automotive electronics design and manufacturing.

The SN74AC240QPWRQ1 belongs to TI's automotive logic portfolio, engineered specifically for signal integrity preservation, EMI resilience, and functional safety compliance in vehicle networking and control subsystems.

FAQ

What is the AEC-Q100 qualification status of the SN74AC240QPWRQ1?

The SN74AC240QPWRQ1 is fully qualified to AEC-Q100 Grade 1 standards, covering operation from −40°C to +125°C ambient temperature, with full stress testing including HTOL, TC, and ESD per automotive requirements. This certification is documented in TI's official AEC-Q100 report for the SN74AC240-Q1 family, confirming its suitability for under-hood and chassis-mounted electronic control units.

Does the SN74AC240QPWRQ1 support mixed-voltage interfacing between 3.3V and 5V systems?

Yes, the SN74AC240QPWRQ1 supports mixed-voltage operation: it accepts input voltages up to 6V regardless of V_CC, allowing direct connection to 5V logic while powered from a 3.3V rail. Its output levels swing rail-to-rail (VOH ≥ V_CC − 0.2V, VOL ≤ 0.44V at 12mA), ensuring reliable interfacing with both 3.3V and 5V receivers without external level shifters.

How does the dual output-enable architecture of the SN74AC240QPWRQ1 improve system reliability?

The SN74AC240QPWRQ1 features two independent output-enable inputs (1OE and 2OE), enabling selective disabling of either 4-bit buffer section. This allows hardware-gated bus arbitration - for example, isolating a failed sensor channel while keeping others active - which enhances fault containment in automotive domain controllers and meets ISO 26262 diagnostic coverage requirements for bus drivers.

What is the maximum capacitive load the SN74AC240QPWRQ1 can drive while maintaining specified timing?

The SN74AC240QPWRQ1 is characterized for CL = 50pF in its switching specifications (t_PLH, t_PHL). At this load and V_CC = 5V, it guarantees t_pd ≤ 6.5ns. Driving heavier loads (e.g., >75pF) increases propagation delay nonlinearly and may violate setup/hold margins; TI recommends limiting trace + receiver capacitance to ≤50pF or adding series termination for longer lines.

Can unused inputs on the SN74AC240QPWRQ1 be left floating in an automotive design?

No - all unused inputs on the SN74AC240QPWRQ1 must be tied to V_CC or GND per TI's layout guidelines. Floating CMOS inputs cause increased ICC, unpredictable logic states, and susceptibility to EMI-induced glitches - unacceptable in automotive applications. TI specifically recommends pullup resistors on OE pins during power-up to ensure defined high-Z state before firmware initialization.