Texas Instruments SN74HC257NG4

Overview

SN74HC257NG4 from Texas Instruments is a quadruple 2-line to 1-line data selector/multiplexer with 3-state non-inverting outputs, operating across 2 V to 6 V supply range. It features 9 ns typical propagation delay at 4.5 V, ±6 mA output drive, and low 80 µA max ICC, enabling bus interface in digital logic systems such as address/data routing in microcontroller peripherals and industrial control I/O expansion.

For engineers reviewing the SN74HC257NG4 datasheet, SN74HC257NG4 pinout, SN74HC257NG4 application, or SN74HC257NG4 equivalent, key selection criteria include its 3-state enable-controlled output behavior, PDIP-16 package compatibility, wide VCC range, and verified timing performance under 50 pF load conditions.

Technical Context

The SN74HC257NG4 implements four independent 2:1 multiplexers sharing common address (A/B) and active-low strobe (G) inputs. Each channel selects between two data inputs (A or B) based on the A/B logic level, while G controls all outputs simultaneously into high-impedance state when high.

Its CMOS HC-family architecture ensures TTL-compatible input thresholds, rail-to-rail output swing, and low static current. The device supports bus-oriented applications by allowing multiple sources to share a common data path without contention, with disable timing (tdis = 32 ns max at 6 V) and enable timing (ten = 32 ns max) tightly specified for synchronous system integration.

Key Specifications

Pinout & Package

SN74HC257NG4 is supplied in a 16-pin plastic dual in-line package (PDIP), body size 19.31 mm × 6.35 mm, with standard through-hole mounting and 2.54 mm pin pitch. Pin numbering follows JEDEC MS-001, with Pin 1 in top-left corner marked by notch or dot.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar data selector applications.

Compared with SN74HC157N, SN74HC257NG4 offers identical functionality with updated packaging and RoHS compliance, while 74LVX257M provides higher speed at 3.3 V but sacrifices 5 V interoperability and through-hole option - making SN74HC257NG4 optimal for mixed-voltage industrial and legacy-compatible designs.

Availability

SN74HC257NG4 is available at Aetrix Electronics and suitable for industrial control systems, test equipment development, and microcontroller-based embedded applications requiring stable component supply, long-lifecycle support, and through-hole assembly compatibility.

Supply support for SN74HC257NG4 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 delivering analog and embedded processing solutions, with over 90 years of innovation in logic, power management, and signal chain technologies.

The SN74HC257NG4 belongs to TI's industry-standard 74HC logic family, designed specifically for robust, low-power, wide-supply-range digital interfacing in industrial, automotive, and communications equipment where reliability and pin-compatibility across generations are critical.

FAQ

What is the maximum clock frequency supported by SN74HC257NG4?

The SN74HC257NG4 does not operate on a clock signal - it is a combinational logic device. Its usable data rate depends on propagation delay and system timing margins. With 9 ns typical tpd at 4.5 V and 50 pF load, it supports reliable data switching up to approximately 30 MHz in well-designed paths, assuming setup/hold times are met by upstream drivers. SN74HC257NG4 timing is fully specified in TI's SCLS224C datasheet Section 5.5.

Can SN74HC257NG4 be used with a 3.3 V microcontroller?

Yes, SN74HC257NG4 operates reliably from 2 V to 6 V, including 3.3 V nominal supply. At 3.3 V, its VOH exceeds 3.1 V and VOL stays below 0.2 V under 6 mA load, ensuring full logic-level compatibility with standard 3.3 V CMOS and TTL inputs. SN74HC257NG4 also accepts 3.3 V as valid VIH/VIL when powered from 5 V, supporting mixed-voltage interfacing without external translators.

Does SN74HC257NG4 require external pull-up resistors on its control inputs?

Yes - TI recommends tying the G (strobe) input to VCC via a pull-up resistor during power-up to ensure outputs remain in high-impedance state until firmware initializes control. A 10 kΩ resistor is typical. Unused A/B or data inputs must also be terminated to VCC or GND per TI application report SCBA004 to prevent floating nodes and erratic behavior. This requirement applies specifically to SN74HC257NG4 due to its CMOS input structure.

Is SN74HC257NG4 pin-compatible with SN74HC257N or SN74HC157N?

Yes - SN74HC257NG4 shares identical PDIP-16 pinout, function table, and electrical characteristics with SN74HC257N and the legacy SN74HC157N. All three use the same JEDEC MS-001 package outline and pin numbering. SN74HC257NG4 is a RoHS-compliant, green-processed variant of SN74HC257N, with identical marking "SN74HC257N" on the package body and full drop-in replacement capability in existing designs.

What thermal considerations apply to SN74HC257NG4 in continuous operation?

SN74HC257NG4 has a junction-to-ambient thermal resistance (RθJA) of 67 °C/W in PDIP-16 package. At maximum rated ICC (80 µA) and worst-case output loading (±6 mA), total power dissipation remains below 50 mW - resulting in negligible self-heating (<4 °C rise) even in still air. No heatsink is required. However, TI specifies maximum operating ambient temperature as 85 °C, so board layout must avoid placement near high-power components or enclosed enclosures exceeding this limit for SN74HC257NG4 reliability.