Texas Instruments SN74AHC244PWR-P

Overview

SN74AHC244PWR-P from Texas Instruments is an octal 3-state noninverting buffer/driver IC designed for bus interface applications requiring high drive strength, voltage-level translation, and low-power CMOS logic. 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 - used in PC motherboard address/data buses and industrial I/O expansion modules.

For engineers reviewing the SN74AHC244PWR-P datasheet, SN74AHC244PWR-P pinout, SN74AHC244PWR-P application, or SN74AHC244PWR-P equivalent, key selection criteria include its 3-state output control architecture, overvoltage-tolerant inputs (up to 5.5V regardless of V_CC), balanced push-pull drive capability, thermal performance in TSSOP-20 package, and compatibility with legacy AHC logic families in mixed-voltage systems.

Technical Context

The SN74AHC244PWR-P implements two independent 4-bit noninverting buffer banks, each enabled by dedicated OE pins (1OE and 2OE). Each bank drives four outputs (e.g., 1Y1–1Y4) from corresponding inputs (1A1–1A4), with boolean function Y_n = A_n. Outputs enter high-impedance state when OE is high, enabling bidirectional bus sharing without external direction control logic.

It uses standard CMOS inputs with ≤10pF input capacitance and ≥1MΩ input resistance, requires fast input transitions (≤20ns/V at 5V), and incorporates internal clamp diodes on all I/O pins for ESD robustness (±2000V HBM). The device is specified for operation from –40°C to +125°C and supports rail-to-rail output swing (V_OL ≤ 0.5V at 8mA, V_OH ≥ 3.8V at 5.5V).

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.50mm × 6.4mm body size, 0.65mm pitch, exposed thermal pad (not electrically connected; may be left floating or tied to GND).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC244APWR and 74AHC244PW,118, the SN74AHC244PWR-P uniquely supports 5V bus interfacing from 3.3V supplies, offers superior thermal performance in TSSOP-20, and maintains consistent timing across its full 2V–5.5V operating range - making it optimal for legacy-compatible, mixed-voltage embedded systems.

Availability

SN74AHC244PWR-P is available at Aetrix Electronics and suitable for PC motherboard bus interfaces, industrial I/O expansion modules, wearable health sensor hubs, and test & measurement equipment requiring stable component supply across extended product lifecycles.

Supply support for SN74AHC244PWR-P 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 company specializing in analog and embedded processing technologies, with leadership in logic, power management, and signal chain solutions.

The SN74AHC244PWR-P belongs to TI's Advanced High-Speed CMOS (AHC) logic family, engineered for high-drive, low-noise bus interfacing in industrial, computing, and instrumentation applications where voltage translation and timing precision are critical.

FAQ

What is the maximum input voltage rating for SN74AHC244PWR-P when operating at 3.3V V_CC?

The SN74AHC244PWR-P supports input voltages up to 5.5V regardless of V_CC level. When operating at 3.3V V_CC, inputs remain overvoltage-tolerant to 5.5V - enabling safe interfacing with 5V peripherals without external level-shifting circuitry. This specification is verified per the Recommended Operating Conditions table in the official datasheet SCLS226N.

Does SN74AHC244PWR-P require external pull-up resistors on its OE pins for proper power-up behavior?

Yes - to ensure all outputs remain in high-impedance state during power-up and power-down, both 1OE and 2OE pins must be held high. TI recommends connecting them to V_CC via pull-up resistors; the minimum value depends on driver sink capability and pin leakage, but 10kΩ is commonly used and validated in application notes. Leaving OE pins floating risks undefined output states and potential bus contention.

What is the typical propagation delay of SN74AHC244PWR-P under 50pF load conditions at 5V V_CC?

The SN74AHC244PWR-P exhibits typical propagation delays of 5.4ns (t_PLH) and 5.4ns (t_PHL) at V_CC = 5V ± 0.5V with 50pF load, as specified in Section 5.7 of the SCLS226N datasheet. These values represent worst-case guaranteed maximums of 8.5ns, ensuring timing margin for synchronous bus designs operating up to 100MHz.

Can SN74AHC244PWR-P drive a 50Ω transmission line directly without series termination?

No - the SN74AHC244PWR-P is not designed for direct 50Ω line driving. Its output impedance is not matched to 50Ω, and its high drive strength (±8mA) causes signal reflections and ringing on unterminated lines. TI application guidance (Section 8.4.1) mandates source-series termination (e.g., 33Ω resistor near the output) for traces longer than 12cm or when driving controlled-impedance lines.

Is the thermal pad on the SN74AHC244PWR-P package electrically connected, and how should it be handled in PCB layout?

The thermal pad on the SN74AHC244PWR-P (TSSOP-20) is not electrically connected to any internal node. Per the Pin Configuration section (Figure 4-3) and Table 4-1 footnote, it may be left floating or connected to GND - but must never be tied to V_CC or signal nets. For optimal thermal performance, TI recommends soldering the pad to a GND plane using ≥4 thermal vias, as shown in Figure 8-4 of the datasheet.