Texas Instruments CD74HC244M

Overview

CD74HC244M from Texas Instruments is a non-inverting octal buffer/line driver with three-state outputs and dual active-low output enables. It operates from 2 V to 6 V, delivers ±7.8 mA output drive at 6 V, exhibits 9 ns typical propagation delay (VCC = 4.5 V, CL = 50 pF), and supports industrial temperature range (–55°C to 125°C). It is used in bidirectional bus interfacing and address/data latching in microcontroller peripheral expansion.

For engineers reviewing the CD74HC244M datasheet, CD74HC244M pinout, CD74HC244M application, or CD74HC244M equivalent, key selection criteria include its non-inverting logic, dual OE control, high-current bus driver capability (±7.8 mA), wide supply range (2–6 V), and compatibility with HC-family timing and noise immunity specs.

Technical Context

The CD74HC244M implements eight independent non-inverting buffer channels, each with three-state output control via two shared active-low enable inputs (1OE and 2OE). Its CMOS architecture ensures rail-to-rail output swing, low static current (≤160 μA over full temperature range), and balanced rise/fall times (10–15 ns typical at 4.5 V).

It features buffered inputs for noise rejection, high fanout (15 LSTTL loads per output), and input voltage thresholds defined as VIH ≥ 3.15 V and VIL ≤ 1.35 V at VCC = 4.5 V - enabling robust interfacing with both HC and legacy TTL systems when operated at 5 V.

Key Specifications

Pinout & Package

CD74HC244M is supplied in a 20-pin SOIC package (body size 12.80 mm × 7.50 mm), optimized for surface-mount assembly and thermal performance (RθJA = 109.1°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC244N and CD74HCT244M, CD74HC244M offers superior noise immunity (30% VCC thresholds) and wider supply flexibility (2–6 V), making it optimal for mixed-voltage embedded systems where power efficiency and robustness outweigh strict TTL compatibility requirements.

Availability

CD74HC244M is available at Aetrix Electronics and suitable for industrial automation, automotive body electronics, and medical device subsystems requiring stable component supply and extended temperature qualification.

Supply support for CD74HC244M 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 decades of experience in high-reliability logic and interface ICs.

CD74HC244M belongs to TI's CD74HC high-speed CMOS logic family, designed for low-power, high-noise-immunity digital interfacing in demanding industrial, automotive, and aerospace applications.

FAQ

What is the maximum output current per pin for CD74HC244M?

The CD74HC244M provides ±7.8 mA output sink/source current per pin at VCC = 6 V, as specified in the Electrical Characteristics table for VOH/VOL under IOH/IOL = ±7.8 mA conditions. This rating ensures reliable driving of 15 LSTTL loads and supports robust signal integrity in noisy environments.

Does CD74HC244M support 3.3 V operation?

Yes, CD74HC244M fully supports 3.3 V operation within its 2 V to 6 V supply range. At VCC = 3.3 V, VIH is guaranteed ≥ 2.31 V and VIL ≤ 1.16 V, and output drive remains sufficient for 3.3 V logic families. Propagation delay increases to ~12 ns typical (CL = 50 pF), maintaining usability in most embedded interfaces.

How are the output enables configured on CD74HC244M?

CD74HC244M has two active-low output enables: 1OE controls outputs Y1–Y4, and 2OE controls outputs Y5–Y8. Both must be low to enable their respective 4-bit groups; either enable asserted high places its outputs in high-impedance state. This allows independent control of two data nibbles on a shared bus.

Is CD74HC244M pin-compatible with CD74HCT244M?

Yes, CD74HC244M and CD74HCT244M share identical pinouts and package dimensions (SOIC-20), including identical pin numbering and function mapping. However, they differ in input threshold specifications and recommended supply ranges - HC uses CMOS-compatible thresholds (VIH = 70% VCC), while HCT uses TTL-compatible thresholds (VIH = 2 V min).

What is the thermal resistance (RθJA) of CD74HC244M in SOIC package?

The junction-to-ambient thermal resistance (RθJA) for CD74HC244M in the SOIC-20 package (M) is 109.1°C/W, as documented in Section 5.3 Thermal Information of the datasheet. This value assumes standard JEDEC 2S2P test board conditions and informs thermal design for continuous operation at elevated ambient temperatures.