Nexperia USA Inc. 74HC244D,653

Overview

74HC244D,653 from Nexperia is an octal non-inverting 3-state buffer/line driver in SO20 package, designed for bidirectional bus interfacing with dual independent output enables (1OE, 2OE). It operates from 2.0 V to 6.0 V, delivers ±7.8 mA output drive at VCC = 4.5 V, and supports industrial temperature range (−40 °C to +125 °C). Used in microcontroller address/data bus expansion and legacy parallel interface isolation.

For engineers reviewing the 74HC244D,653 datasheet, 74HC244D,653 pinout, 74HC244D,653 application, or 74HC244D,653 equivalent, key selection criteria include 3-state timing (tpd ≤ 22 ns @ VCC = 4.5 V), CMOS-level input compatibility, dual enable control granularity, and SO20 thermal performance (Ptot = 500 mW, derates above 109 °C).

Technical Context

This device implements two independent 4-bit non-inverting buffers, each controlled by a dedicated active-low output enable (1OE for Y0–Y3, 2OE for Y0–Y3 of second group). Inputs feature clamp diodes enabling overvoltage-tolerant interfacing via current-limiting resistors. The architecture avoids bus contention by ensuring high-impedance isolation when either enable is HIGH.

Static logic levels are defined per JEDEC JESD7A: VIH ≥ 3.15 V (VCC = 4.5 V) for HC variant; VOL ≤ 0.26 V and VOH ≥ 3.98 V under 6 mA load. Dynamic behavior includes matched tPLH/tPHL propagation delays and tightly specified enable/disable times (ten/tdis ≤ 30 ns @ VCC = 4.5 V), critical for synchronous bus handshaking.

Key Specifications

Pinout & Package

74HC244D,653 uses the SO20 (SOT163-1) plastic small outline package: 20-pin, 7.5 mm body width, 1.27 mm pitch, gull-wing leads. Thermal resistance θJA = 80 K/W (JEDEC Std. 2s2p board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74HCT244D,653, the HC variant offers wider voltage flexibility but stricter input thresholds; versus SN74LVC244APWR, it trades speed and size for 5 V interoperability and ruggedness in harsh environments.

Availability

74HC244D,653 is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, legacy PC expansion interfaces, and test equipment signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for 74HC244D,653 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

Nexperia is a global semiconductor expert delivering high-performance, reliable logic, discrete, and MOSFET solutions with focus on efficiency and sustainability.

The 74HC244 belongs to Nexperia's industry-standard HC logic family, engineered for robust bus interfacing in industrial, automotive, and computing applications where wide supply range and high noise immunity are essential.

FAQ

What is the maximum clock frequency supported by 74HC244D,653?

The 74HC244D,653 is not a clocked device-it has no internal clock and operates asynchronously. Its usable data rate depends on propagation delay (≤22 ns @ 4.5 V) and system setup/hold timing. For a 15 pF bus load, it reliably supports bidirectional data transfer up to ~20 MHz with appropriate board layout and termination.

Can 74HC244D,653 drive a 50 pF load while maintaining logic levels?

Yes-output specifications guarantee VOH ≥ 3.98 V and VOL ≤ 0.26 V at ±7.8 mA drive into 15 pF. At 50 pF, rise/fall times increase (~18 ns @ VCC = 4.5 V), but logic levels remain valid as long as trace impedance and slew rate meet system timing margins. Derate output current if sustained high-frequency switching is required.

Is there a pin-compatible 74HC244 variant with improved ESD protection?

74HC244D,653 already meets ANSI/ESDA/JEDEC JS-001 Class 2 (≥2000 V HBM) and JS-002 Class C3 (≥1000 V CDM). Nexperia does not offer a pin-compatible revision with enhanced ESD beyond these certified levels; system-level protection (e.g., TVS diodes) is recommended for environments exceeding IEC 61000-4-2 Level 4.

How should unused inputs and outputs be handled?

Unused inputs must be tied HIGH or LOW (not left floating) to prevent increased ICC and noise susceptibility. Unused outputs should be disabled via their respective OE pin (1OE or 2OE = HIGH) to avoid contention. GND and VCC pins require solid plane connections; the exposed pad on QFN variants is not present in SO20 (74HC244D,653) and thus not applicable.