Texas Instruments SN74F244NSR

Overview

SN74F244NSR from Texas Instruments is an octal noninverting 3-state buffer/line driver IC designed for memory address driving, bus interfacing, and clock distribution in TTL-compatible digital systems. It features two independent 4-bit channels with separate active-low output-enable (OE) inputs, 5 V nominal supply operation, ±128 mA low-state output drive, and 6.5 ns typical propagation delay at 5 V.

For engineers reviewing the SN74F244NSR datasheet, SN74F244NSR pinout, SN74F244NSR application, or SN74F244NSR equivalent, this page delivers verified electrical specs, package-validated pin functions, real-world use cases in legacy industrial control and instrumentation buses, and confirmed drop-in alternatives for obsolescence mitigation and second-source procurement.

Technical Context

The SN74F244NSR implements dual 4-bit noninverting buffer architecture with symmetrical OE control per group - 1OE enables Y1–Y4 outputs from A1–A4 inputs, while 2OE controls Y1–Y4 outputs from A1–A4 inputs on the second channel. Each output transitions to high-impedance when its respective OE is high.

It operates strictly within the TTL logic family: VIH = 2 V min, VIL = 0.8 V max, VOH = 2.4 V min (IOH = −12 mA), VOL = 0.55 V max (IOL = 64 mA), and supports 50 pF capacitive loads with guaranteed tPLH/tPHL ≤ 6.2 ns at VCC = 4.5–5.5 V and TA = 0–70°C.

Key Specifications

Pinout & Package

SOP (Small Outline Package) NS variant: 20-pin surface-mount, 0.3 inch body width, 1.27 mm lead pitch, 2.65 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1 (unlimited floor life).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS244N and SN74HC244PW, the SN74F244NSR delivers superior speed and drive strength for legacy TTL systems but lacks modern voltage flexibility or ultra-low power operation - making it optimal for maintaining performance in existing F-series designs.

Availability

SN74F244NSR is available at Aetrix Electronics and suitable for industrial control panels, legacy test instrumentation, and military-grade subsystems requiring stable component supply and long-term obsolescence management.

Supply support for SN74F244NSR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74F244NSR belongs to TI's 74F TTL logic family - engineered for high-speed, high-drive digital interfacing in mission-critical legacy systems where reliability and deterministic timing supersede power efficiency.

FAQ

What is the maximum operating frequency supported by the SN74F244NSR?

The SN74F244NSR does not specify a maximum clock frequency in its datasheet. Instead, its timing is characterized by propagation delay: tPLH/tPHL ≤ 6.2 ns (max) at CL = 50 pF and VCC = 4.5–5.5 V. This supports reliable operation in synchronous bus systems up to approximately 80 MHz, assuming adequate setup/hold margins and controlled trace impedance. The SN74F244NSR is not intended for continuous clock distribution above 25 MHz without careful board-level timing analysis.

Is the SN74F244NSR pin-compatible with the SN74LS244?

Yes, the SN74F244NSR is pin-compatible with the SN74LS244 in the same SOP-20 (NS) package. Both share identical pin numbering, terminal functions (A1–A4, B1–B4, Y1–Y4, Z1–Z4, 1OE, 2OE, VCC, GND), and mechanical footprint. However, the SN74F244NSR delivers higher drive current (128 mA vs. 24 mA) and faster propagation (6.2 ns vs. 20 ns), so direct substitution may require verification of downstream load compatibility and timing closure.

Does the SN74F244NSR support 3.3 V operation?

No, the SN74F244NSR does not support 3.3 V operation. Its recommended supply voltage range is strictly 4.5 V to 5.5 V, and absolute maximum ratings prohibit VCC below 4.5 V. Operating the SN74F244NSR at 3.3 V will result in undefined logic behavior, insufficient output voltage levels (VOH < 2.0 V), and potential failure to meet TTL input thresholds of downstream devices. For 3.3 V systems, consider CMOS alternatives like SN74LVC244A with appropriate level-shifting.

What is the thermal performance of the SN74F244NSR in continuous operation?

The SN74F244NSR has a specified operating free-air temperature range of 0°C to 70°C and a storage range of −65°C to 150°C. Under worst-case conditions (VCC = 5.5 V, all outputs sinking 128 mA), ICC reaches 90 mA, yielding ~0.5 W power dissipation. In standard JEDEC-standard PCB layouts with 1 oz copper, the NS package exhibits a θJA of approximately 120°C/W - resulting in ~60°C junction rise above ambient. Adequate airflow or localized copper pour is recommended for sustained full-load operation near 70°C ambient.

Can the SN74F244NSR be used as a level translator between 5 V and 3.3 V logic?

No, the SN74F244NSR cannot reliably serve as a bidirectional level translator. Its inputs require TTL-compatible thresholds (VIH ≥ 2.0 V, VIL ≤ 0.8 V), and its outputs swing from 0–0.55 V (low) and 2.4–3.3 V (high) - insufficient to drive 3.3 V CMOS inputs (VIH ≥ 2.31 V) robustly. While a 5 V → 3.3 V unidirectional interface may function marginally under light loads, TI does not characterize or guarantee such use. Dedicated level translators like TXB0108 are required for compliant 5 V ↔ 3.3 V translation.