Texas Instruments SN74BCT244N

Overview

SN74BCT244N from Texas Instruments is an octal noninverting 3-state buffer/line driver IC designed for memory address and bus driving applications. It features two independent 4-bit sections with active-low output-enable (OE) inputs, 5-V supply operation, ±64 mA low-level output drive, and 0°C to 70°C industrial temperature range - enabling reliable interfacing between TTL/CMOS logic and high-capacitance data buses in embedded control systems.

For engineers reviewing the SN74BCT244N datasheet, SN74BCT244N pinout, SN74BCT244N application, or SN74BCT244N equivalent, this device serves as a legacy-compatible, high-drive bus interface solution where TTL-level compatibility, low ICCZ quiescent current, and robust ESD protection (>2000 V) are required in industrial and legacy computing designs.

Technical Context

The SN74BCT244N implements BiCMOS circuitry combining bipolar input stages for TTL-compatible thresholds and CMOS output stages for high-current drive and low power consumption. Its P-N-P input structure reduces DC loading on upstream drivers, while its 3-state outputs support bidirectional bus arbitration without external logic.

Each of the two 4-bit sections operates independently: when OE is low, A→Y data passes transparently; when OE is high, Y outputs enter high-impedance state. The device supports 50-pF load switching with tPLH/tPHL ≤ 5 ns at 5 V, and maintains VOH ≥ 2.4 V at IOH = −12 mA and VOL ≤ 0.55 V at IOL = 64 mA.

Key Specifications

Pinout & Package

SN74BCT244N uses a 20-pin plastic dual in-line package (PDIP-N), 300-mil width, with 0.1-inch lead pitch and through-hole mounting. Pin 1 is located at the top-left corner adjacent to the notch or dot marking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LS244N, SN74BCT244N delivers 2.7× higher output current and 5× faster switching with lower quiescent power; compared with SN74ACT244N, it retains native TTL input compatibility critical for legacy system upgrades without redesigning upstream logic.

Availability

SN74BCT244N is available at Aetrix Electronics and suitable for memory address buffering, industrial backplane interfacing, and legacy bus expansion requiring stable component supply and long-term obsolescence management.

Supply support for SN74BCT244N 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 U.S.-based semiconductor company founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.

The SN74BCT244N belongs to TI's legacy 74BCT logic family, engineered specifically to enhance bus-driving performance and density in memory and clock distribution systems while maintaining pin-and-function compatibility with earlier 74-series devices.

FAQ

What is the maximum output sink current rating for SN74BCT244N?

The SN74BCT244N is rated for 64 mA per output in the low state (IOL), tested at VCC = 4.5 V and specified over the full 0°C to 70°C operating range. This value ensures reliable logic LOW assertion into heavy bus loads, including multiple TTL inputs or long PCB traces, while maintaining VOL ≤ 0.55 V - a key requirement for noise margin compliance in industrial systems using the SN74BCT244N.

Does SN74BCT244N support 3.3-V input logic levels?

No, SN74BCT244N does not reliably accept 3.3-V inputs as valid HIGH. Its TTL-compatible input thresholds require VIH ≥ 2.0 V (min) and VIL ≤ 0.8 V (max) - while 3.3-V CMOS outputs often exceed VIH, marginal cases (e.g., weak drivers or noisy rails) may fail. For guaranteed interoperability with 3.3-V systems, level-shifting or a CMOS-input alternative like SN74ACT244N is recommended instead of relying on the SN74BCT244N.

Can SN74BCT244N be used in place of SN74LS244N without circuit modification?

Yes, SN74BCT244N is pin-compatible and functionally equivalent to SN74LS244N, sharing identical pinout, logic behavior, and 20-pin PDIP packaging. However, due to its higher output drive (64 mA vs. 24 mA) and faster switching (≤5 ns vs. ~20 ns), users must verify that downstream loads can tolerate the increased edge rates and that power delivery supports higher peak currents - especially when multiple SN74BCT244N outputs switch simultaneously.

What is the purpose of the P-N-P input structure in SN74BCT244N?

The P-N-P input stage in SN74BCT244N minimizes DC loading on upstream drivers by limiting input current: IIH is capped at 20 µA and IIL at −1 mA. This preserves fan-out capability - for example, a single 74LS00 gate can drive up to 20 SN74BCT244N inputs versus only 10–15 with standard TTL buffers. This design choice directly enhances system-level signal integrity and reduces cumulative loading effects across large bus networks using the SN74BCT244N.

Is SN74BCT244N RoHS compliant?

Yes, SN74BCT244N is RoHS compliant, featuring NiPdAu (NIPDAU) lead finish and meeting EU Directive 2011/65/EU requirements. Per TI's Package Option Addendum, the part carries "Yes" in the RoHS column and is rated for lead-free reflow (Level-1-260°C-UNLIM). This compliance applies to both SN74BCT244N and SN74BCT244N.A variants, confirming suitability for modern environmentally regulated production using the SN74BCT244N.