NXP Semiconductors 74HCT157N,652

Overview

74HCT157N,652 from NXP Semiconductors is a quad 2-input CMOS multiplexer with non-inverting outputs, active-low enable (E), and common data select (S). It operates from 4.5 V to 5.5 V, supports −40 °C to +125 °C ambient range, delivers propagation delays as low as 13 ns (VCC = 4.5 V), and is pin-compatible with LSTTL. It routes four parallel data bits from dual sources in industrial control logic and register file selection.

For engineers reviewing the 74HCT157N,652 datasheet, 74HCT157N,652 pinout, 74HCT157N,652 application, or 74HCT157N,652 equivalent, this device serves as a logic-level 4-pole, 2-position switch for deterministic data path selection, function generation, and bus multiplexing in legacy TTL-interfaced digital systems.

Technical Context

The 74HCT157N,652 implements four independent 2:1 multiplexers sharing one select (S) and one active-low enable (E) input. Each output (1Y–4Y) follows Y = E̅ × (I₁ × S + I₀ × S̅), enabling simultaneous 4-bit data routing from either of two 4-bit sources. Its HCT logic family ensures TTL-compatible input thresholds (VIH = 2.0 V min, VIL = 0.8 V max at VCC = 4.5–5.5 V).

It features true (non-inverting) outputs-distinguishing it from the inverting-output 74HC158-and integrates ESD protection exceeding 2000 V HBM and 200 V MM. The device is specified across industrial and extended temperature ranges and supports dynamic operation up to 25 MHz (typical) with CL = 50 pF.

Key Specifications

Pinout & Package

74HCT157N,652 uses a plastic dual in-line package (DIP16, SOT38-4) with 300-mil body width, through-hole mounting, and 16 leads. Pin 1 is the common data select (S); pins 2/5/11/14 are source-0 inputs (1I0–4I0); pins 3/6/10/13 are source-1 inputs (1I1–4I1); pins 4/7/9/12 are outputs (1Y–4Y); pin 8 is GND; pin 15 is active-low enable (E); pin 16 is VCC.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad 2-input multiplexer applications.

Compared with 74HC157N,652 and SN74LS157N, the 74HCT157N,652 uniquely balances TTL input compatibility, CMOS power efficiency (ICC < 160 µA), and 13 ns propagation speed-making it optimal for upgrading legacy systems while maintaining signal integrity and thermal performance.

Availability

74HCT157N,652 is available at Aetrix Electronics and suitable for industrial control systems, test equipment design, legacy microprocessor expansion, and programmable logic implementation requiring stable component supply and long-term obsolescence management.

Supply support for 74HCT157N,652 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

NXP Semiconductors is a global semiconductor leader specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with core expertise in high-reliability logic, RF, and MCU technologies.

The 74HCT157N,652 belongs to NXP's industry-standard 74HCT logic family, designed specifically to bridge TTL and CMOS domains with robust input thresholds, low power consumption, and extended temperature operation for mission-critical digital interfaces.

FAQ

What is the maximum operating frequency supported by the 74HCT157N,652?

The 74HCT157N,652 does not specify a hard maximum clock frequency, but its propagation delay (tpd ≤ 27 ns at VCC = 4.5 V) and transition time (tt ≤ 15 ns) support reliable operation up to approximately 25 MHz in typical 50 pF load conditions. System-level timing must account for setup/hold margins relative to the controlling S and E signals. For the 74HCT157N,652, actual usable frequency depends on board layout, load capacitance, and supply stability-not a fixed rated clock.

Does the 74HCT157N,652 require external pull-up or pull-down resistors on its control inputs?

No, the 74HCT157N,652 does not require external pull-up or pull-down resistors on S or E inputs because its CMOS inputs have negligible leakage current (<1.0 µA) and defined VIH/VIL thresholds. However, floating inputs must be avoided: unconnected S or E pins can cause metastability or increased ICC. For robust operation, tie unused control inputs to VCC (for E) or GND/VCC (for S) using PCB traces-not relying on internal structures. This applies directly to the 74HCT157N,652 in all operating modes.

How does the enable (E) pin function in the 74HCT157N,652?

The enable (E) pin on the 74HCT157N,652 is active LOW: when E = HIGH, all four outputs (1Y–4Y) are forced LOW regardless of S or input states; when E = LOW, outputs reflect the multiplexed data determined by S. This allows global gating of the entire 4-bit path-critical for bus arbitration, power-gated subsystems, or fault-safe shutdown. The 74HCT157N,652's E pin has identical electrical specs to other inputs (VIH ≥ 2.0 V, VIL ≤ 0.8 V) and contributes ≤490 µA additional ICC when switching.

Can the 74HCT157N,652 operate at 3.3 V supply voltage?

No, the 74HCT157N,652 is not characterized or guaranteed for operation at 3.3 V. Its recommended operating conditions specify VCC = 4.5 V to 5.5 V only. At 3.3 V, input thresholds (VIH ≥ 2.0 V) become marginal, propagation delay increases significantly, and output drive degrades below specification. For 3.3 V systems, use the 74LVC157 or 74AUP1G157 families instead. The 74HCT157N,652 must be operated within its published 4.5–5.5 V range to meet datasheet performance.

Is the 74HCT157N,652 pin-compatible with the 74HC157N,652?

Yes, the 74HCT157N,652 is pin-compatible with the 74HC157N,652 in the same package (DIP16, SOT38-4), sharing identical pinout, footprint, and terminal assignments. However, they differ electrically: 74HCT157N,652 has TTL-compatible inputs (VIH = 2.0 V min), while 74HC157N,652 uses CMOS thresholds (VIH = 3.15 V min at VCC = 4.5 V). Swapping them requires verifying driver compatibility-74HCT157N,652 accepts standard TTL outputs; 74HC157N,652 does not.