Texas Instruments SN74AHC244NS

Overview

SN74AHC244NS from Texas Instruments is an octal 3-state noninverting buffer/driver IC designed for bus interface, memory address driving, and clock distribution in high-density digital systems. It operates from 2V to 5.5V, delivers ±8mA output drive at 5V, supports 10ns typical propagation delay (VCC = 5V, CL = 15pF), and features dual independent 4-bit banks with separate 3-state enables - used in PC motherboard I/O expansion and industrial backplane buffering.

For engineers reviewing the SN74AHC244NS datasheet, SN74AHC244NS pinout, SN74AHC244NS application, or SN74AHC244NS equivalent, key selection criteria include its 20-pin SOP package, dual OE control architecture, CMOS input compatibility up to 5.5V, balanced push-pull 3-state outputs, and thermal performance metrics (RθJA = 77.6°C/W) critical for compact board layouts.

Technical Context

The SN74AHC244NS implements two independent 4-bit noninverting buffer banks, each controlled by a dedicated output-enable input (1OE, 2OE). Each bank drives four outputs (e.g., 1Y1–1Y4, 2Y1–2Y4) with identical logic function Yn = An and simultaneous 3-state control.

Its CMOS inputs tolerate voltages up to 5.5V regardless of VCC, enabling level translation from higher-voltage logic domains into 3.3V or 2.5V buses. Outputs exhibit balanced sourcing/sinking capability (±8mA at 5V), fast edge rates (20 ns/V max input transition rate), and low dynamic noise (VOL(P) ≤ 0.5V, VOH(V) ≥ 4.8V).

Key Specifications

Pinout & Package

SN74AHC244NS is supplied in a 20-pin SOP (Small Outline Package) with 12.60mm × 7.8mm body size and 12.6mm × 5.30mm footprint. The package uses gull-wing leads, is RoHS-compliant, and rated for –40°C to +125°C operating temperature.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV244A and 74AHC244PW, the SN74AHC244NS offers the optimal balance of 5V-speed performance, thermal efficiency in standard SOP footprint, and robust 5.5V input tolerance - making it the preferred choice for industrial and computing applications requiring reliable bus driving without layout compromise.

Availability

SN74AHC244NS is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial backplane buffering, and wearable health sensor hub designs requiring stable component supply across multi-year production cycles.

Supply support for SN74AHC244NS 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and consumer applications.

The SN74AHC244NS belongs to TI's AHC logic family - engineered for high-speed, low-power, 3-state bus interface applications where voltage translation, noise immunity, and thermal reliability are critical.

FAQ

What is the maximum operating temperature for SN74AHC244NS?

The SN74AHC244NS is rated for operation from –40°C to +125°C ambient temperature. This extended range is validated per JEDEC JESD78 and supports deployment in industrial control cabinets and automotive under-hood environments where thermal cycling exceeds commercial-grade limits. The device's RθJA of 77.6°C/W in SOP package ensures safe junction temperatures under typical 100mW power dissipation.

Does SN74AHC244NS support level shifting between different supply domains?

Yes, SN74AHC244NS supports true level shifting: its inputs tolerate up to 5.5V regardless of VCC, allowing 5V logic signals to be safely driven into a 3.3V- or 2.5V-powered SN74AHC244NS. Outputs swing rail-to-rail (0V to VCC), so output levels conform strictly to the local VCC domain - enabling bidirectional voltage translation when combined with appropriate pull-up configurations on 3-state outputs.

How should unused inputs be terminated on SN74AHC244NS?

All unused inputs on SN74AHC244NS must be tied to a valid logic level - either VCC or GND - using direct connections or 10kΩ pull-up/down resistors. Floating CMOS inputs cause excessive current draw, oscillation, and potential latch-up. This requirement applies to both data inputs (1A1–1A4, 2A1–2A4) and enable inputs (1OE, 2OE); leaving 1OE or 2OE floating will result in unpredictable 3-state behavior.

What is the recommended bypass capacitor for SN74AHC244NS?

A 0.1µF ceramic capacitor is required between VCC (pin 20) and GND (pin 10), placed within 3mm of the pins with minimal trace inductance. For improved high-frequency noise suppression, TI recommends paralleling this with a 1µF capacitor. The capacitor must connect directly to the IC's power pins - not shared with other devices - to maintain signal integrity and prevent ground bounce during simultaneous output switching.

Can SN74AHC244NS drive a 50pF load at 50MHz?

SN74AHC244NS is characterized for 50pF loads at DC to ~100MHz, with tPLH/tPHL ≤ 8.5ns (VCC = 5V). At 50MHz, edge rates remain well within specification (20ns/V input slew limit), and dynamic noise remains controlled (VOL(P) ≤ 0.5V). However, trace length must be limited to ≤12cm and source termination (e.g., 22Ω series resistor) applied to prevent reflections - as confirmed in TI's Application Report SCLA015.