Texas Instruments SN74AHC244DWR

Overview

SN74AHC244DWR from Texas Instruments is an octal 3-state noninverting buffer/driver IC designed for high-density bus interfacing in memory-address, clock, and data transmission systems. It operates across 2V–5.5V V_CC, delivers ±8mA output drive at 5V, supports 10ns typical propagation delay (t_PLH/t_PHL) under 50pF load, and features dual independent 4-bit banks controlled by separate OE pins - enabling selective bus isolation in PC motherboard I/O expansion and industrial controller backplanes.

For engineers reviewing the SN74AHC244DWR datasheet, SN74AHC244DWR pinout, SN74AHC244DWR application, or SN74AHC244DWR equivalent, key selection criteria include its 20-pin SOIC (DW) package with 12.8mm × 10.3mm footprint, balanced CMOS push-pull/3-state outputs, overvoltage-tolerant inputs up to 5.5V, and verified performance in high-speed trace-length-critical interfaces such as PCIe auxiliary buses and sensor hub interconnects.

Technical Context

The SN74AHC244DWR 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 Y = A and high-impedance state when OE is high. Its CMOS architecture ensures rail-to-rail output swing and symmetrical sourcing/sinking capability.

It supports mixed-voltage operation: inputs tolerate up to 5.5V regardless of V_CC (enabling level translation), while outputs swing fully between GND and V_CC. The device meets JESD17 latch-up immunity (>250mA), HBM ESD rating (±2000V), and operates from –40°C to +125°C ambient temperature.

Key Specifications

Pinout & Package

SN74AHC244DWR is packaged in a 20-pin SOIC (DW) with 12.80mm × 10.3mm body size and standard 1.27mm pitch. Pin 1 is marked via notch or bevel; Pin 10 is GND, Pin 20 is V_CC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74LVC244APW and SN74AHCT244N, SN74AHC244DWR uniquely balances wide V_CC range (2–5.5V), 5.5V input tolerance, and robust 125°C operation - making it optimal for mixed-voltage industrial and automotive-qualified designs where voltage flexibility and thermal resilience outweigh raw speed or legacy TTL compatibility.

Availability

SN74AHC244DWR is available at Aetrix Electronics and suitable for PC motherboard I/O expansion, industrial PLC backplane interface, and wearable health sensor hub applications requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for SN74AHC244DWR 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 connectivity technologies, with over 90 years of innovation in high-reliability logic and interface solutions.

The SNx4AHC244 family was engineered for high-density, high-speed bus interfacing in memory-address drivers, clock distribution networks, and industrial backplane systems - prioritizing voltage flexibility, noise immunity, and thermal robustness.

FAQ

What is the maximum input voltage rating for SN74AHC244DWR?

The SN74AHC244DWR accepts input voltages up to 5.5V regardless of V_CC level - a feature confirmed in Section 5.3 Recommended Operating Conditions. This overvoltage tolerance allows direct interfacing with 5V peripherals even when powered from 3.3V or 2.5V supplies, eliminating external level-shifting circuitry in mixed-voltage designs. The absolute maximum input rating remains 7V per Section 5.1.

Does SN74AHC244DWR support operation at 2.5V V_CC?

Yes, SN74AHC244DWR is fully specified for operation at 2.5V V_CC per its 2V–5.5V operating range in Section 5.3. At 2.5V, it delivers ±4mA output drive (I_OL/I_OH), maintains VIH/VIL thresholds scaled to 70%/30% of V_CC, and achieves typical propagation delay of ≤10ns at 15pF load - making it suitable for low-voltage portable and battery-powered applications where power efficiency is critical.

How are the two output-enable pins (1OE and 2OE) used in SN74AHC244DWR?

In SN74AHC244DWR, Pin 1 (1OE) controls Bank 1 outputs (1Y1–1Y4), and Pin 19 (2OE) controls Bank 2 outputs (2Y1–2Y4). Both are active-low: driving either OE low enables its respective four outputs; driving it high places those outputs in high-impedance state. This independent control allows simultaneous or staggered bus isolation - for example, holding CPU address lines active while tri-stating peripheral data lines during DMA cycles.

What is the thermal resistance (RθJA) of the SN74AHC244DWR SOIC package?

The SN74AHC244DWR in DW (SOIC-20) package has a junction-to-ambient thermal resistance (RθJA) of 81.1°C/W, as documented in Section 5.4 Thermal Information. This value assumes standard JEDEC 2-layer board conditions. For continuous 8mA output current per pin at 5V, total power dissipation remains below 100mW - well within safe thermal limits even at +125°C ambient, provided adequate PCB copper area is used for heat spreading.

Can unused inputs on SN74AHC244DWR be left floating?

No, unused inputs on SN74AHC244DWR must never be left floating. As stated in Section 5.3 Note 1 and Section 7.3.3, all unused CMOS inputs must be terminated to V_CC or GND to prevent oscillation, excessive power consumption, and potential device damage. A 10kΩ pull-up or pull-down resistor is recommended for unconnected inputs - especially critical for OE pins to ensure predictable 3-state behavior during power-up sequences.