Texas Instruments SN74HCS244QPWRQ1

Overview

SN74HCS244QPWRQ1 from Texas Instruments is an AEC-Q100 Grade 1 automotive octal buffer with Schmitt-trigger inputs and 3-state outputs, configured as two independent 4-channel banks each controlled by dedicated active-low output enable pins. It operates from 2 V to 6 V, delivers ±7.8 mA output drive at 6 V, and draws only 100 nA typical supply current - enabling robust signal conditioning in noisy vehicle subsystems such as body control modules and infotainment interfaces.

For engineers reviewing the SN74HCS244QPWRQ1 datasheet, SN74HCS244QPWRQ1 pinout, SN74HCS244QPWRQ1 application, or SN74HCS244QPWRQ1 equivalent, key selection criteria include its dual-bank 3-state architecture, Schmitt-trigger noise immunity (ΔVT ≥ 0.6 V at 6 V), wettable-flank VQFN-20 package for AOI-compatible solder joint inspection, and guaranteed operation from –40°C to +125°C ambient.

Technical Context

The SN74HCS244QPWRQ1 implements eight independent CMOS push-pull buffers partitioned into two functionally isolated banks (Bank 1: pins 1A1–1A4/1Y1–1Y4; Bank 2: pins 2A1–2A4/2Y1–2Y4), each with dedicated active-low output enable (1OE, 2OE). Its Schmitt-trigger inputs provide hysteresis (ΔVT = 0.6 V min at 6 V) to reject slow-edge or high-amplitude noise on signals from switches, sensors, or legacy buses.

Each output supports ±7.8 mA drive at 6 V while maintaining VOH ≥ 5.4 V and VOL ≤ 0.33 V under load, and achieves propagation delay as low as 6 ns (typ) at 6 V with CL = 50 pF. The device uses balanced CMOS output stages and includes clamp diodes on all I/O pins per AEC-Q100 requirements.

Key Specifications

Pinout & Package

VQFN-20 (WRKS) package with wettable flanks (4.50 mm × 2.50 mm body, 0.5 mm pitch); thermal pad exposed on bottom for enhanced thermal dissipation and AOI-compatible side-fillet inspection.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCS244QPWRQ1, the TSSOP variant offers easier hand-soldering but sacrifices thermal performance and AOI capability, while the MC74VHC244DTG omits automotive qualification entirely - making SN74HCS244QPWRQ1 the sole option meeting full AEC-Q100 Grade 1 requirements in a wettable-flank QFN.

Availability

SN74HCS244QPWRQ1 is available at Aetrix Electronics and suitable for automotive body electronics, ADAS sensor interfaces, infotainment system isolation, and EPS feedback conditioning requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74HCS244QPWRQ1 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 delivering AEC-Q100-qualified components for safety-critical vehicle systems.

The SN74HCS244QPWRQ1 belongs to TI's HCS logic family - designed specifically for automotive signal integrity, featuring Schmitt-trigger inputs, ultra-low power, and robust ESD protection to meet stringent vehicle ECU requirements.

FAQ

What is the maximum operating temperature for the SN74HCS244QPWRQ1?

The SN74HCS244QPWRQ1 is rated for ambient operation from –40°C to +125°C per AEC-Q100 Grade 1 qualification. This specification is validated across process corners and ensures functional reliability in under-hood and transmission-control environments where thermal stress is extreme. The device's thermal resistance (RθJA = 83.2°C/W in WRKS package) supports sustained operation within this range when PCB layout follows TI's recommended copper flood and decoupling practices.

Does the SN74HCS244QPWRQ1 require external pull-up resistors on its OE pins?

Yes - to guarantee high-impedance outputs during power-up and power-down sequences, both 1OE and 2OE pins must be tied to VCC via external pull-up resistors. TI recommends values based on driver sink capability and pin leakage (±100 nA max), typically 10 kΩ. Leaving OE pins floating risks undefined output states that could cause bus contention or excessive current draw in multi-drop configurations where SN74HCS244QPWRQ1 interfaces with other 3-state devices.

Can the SN74HCS244QPWRQ1 drive a 100-pF load reliably?

No - the SN74HCS244QPWRQ1 is characterized and specified for loads ≤50 pF. Driving 100 pF exceeds the capacitive limit stated in the datasheet's Application and Implementation section and will degrade switching performance: propagation delay increases, transition times lengthen, and output voltage margins (VOH/VOL) may fall out of spec. For higher capacitance, add series damping resistors or use a buffer with higher Cpd rating - the SN74HCS244QPWRQ1 itself must operate within its 50-pF design envelope to meet published timing and DC specs.

Is the thermal pad on the SN74HCS244QPWRQ1 WRKS package required to be connected to ground?

No - the thermal pad on the SN74HCS244QPWRQ1 WRKS package may be connected to GND or left electrically floating, as explicitly stated in the Pin Functions table. TI does not require grounding; however, connecting it to GND improves thermal resistance (RθJB drops to 57.4°C/W) and provides a low-impedance path for noise suppression. Never connect the pad to VCC or signal nets - doing so violates the absolute maximum ratings and risks latch-up or ESD damage.

How does the Schmitt-trigger input of the SN74HCS244QPWRQ1 improve noise immunity compared to standard CMOS inputs?

The SN74HCS244QPWRQ1 Schmitt-trigger inputs provide hysteresis (ΔVT ≥ 0.6 V at 6 V), meaning the threshold for detecting a rising edge (VT+ ≈ 4.2 V) differs significantly from that for a falling edge (VT– ≈ 3.6 V). This gap rejects noise spikes up to ±300 mV peak-to-peak without causing multiple transitions - unlike standard CMOS inputs, which have near-identical thresholds and oscillate on noisy edges. As a result, SN74HCS244QPWRQ1 eliminates false triggering from EMI on long harnesses or mechanical switch bounce without external RC filters.