Nexperia USA Inc. 74HCT238DB,118

Overview

74HCT238DB,118 from Nexperia is a 3-to-8 line decoder/demultiplexer with TTL-compatible inputs, active-HIGH mutually exclusive outputs (Y0–Y7), three enable inputs (E1, E2 active LOW; E3 active HIGH), and operation across 4.5 V to 5.5 V supply. It supports memory chip select decoding and parallel expansion to 1-of-32 via four ICs + one inverter, with propagation delay as low as 18 ns at VCC = 4.5 V and CL = 15 pF.

For engineers reviewing the 74HCT238DB,118 datasheet, 74HCT238DB,118 pinout, 74HCT238DB,118 application, or 74HCT238DB,118 equivalent, this device is selected for precise address decoding in industrial microcontroller peripherals, FPGA I/O expansion, and multi-chip select logic where TTL-level compatibility, low static current (<160 µA), and guaranteed -40 °C to +125 °C operation are required.

Technical Context

The 74HCT238DB,118 implements combinational logic decoding of three binary address lines (A0–A2) into eight independent outputs, with strict mutual exclusivity enforced only when E1 = LOW, E2 = LOW, and E3 = HIGH. Its enable architecture enables cascading without external gating logic.

Input thresholds are fixed at VIH = 2.0 V (min) and VIL = 0.8 V (max) under VCC = 4.5–5.5 V, ensuring robust TTL-level interfacing. Output drive capability is ±4.0 mA at VOH ≥ 3.7 V and VOL ≤ 0.4 V, supporting direct connection to standard CMOS/TTL loads.

Key Specifications

Pinout & Package

74HCT238DB,118 is supplied in SOT338-1 (SO20) package per historical ordering data, though current documentation references SO16 (SOT109-1), TSSOP16 (SOT403-1), and DHVQFN16 (SOT763-1). The SOT338-1 variant is obsolete per Rev. 7 (2021); J-column data confirms DB suffix maps to SOT338-1, but pin count and layout match SO16 functional mapping. Physical pinout aligns with SO16: 16-pin plastic small outline, 3.9 mm body width, 1.27 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 3-to-8 decoder applications.

Compared with 74HC238D,118, the 74HCT238DB,118 offers superior TTL interoperability and lower static current, while SN74LS238N trades efficiency for backward compatibility-making the HCT variant optimal for new designs requiring robust 5 V logic integration.

Availability

74HCT238DB,118 is available at Aetrix Electronics and suitable for memory subsystems, FPGA peripheral expansion, microcontroller I/O multiplexing, and automotive body electronics requiring stable component supply across extended temperature ranges.

Supply support for 74HCT238DB,118 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 logic, analog, and MOSFET solutions with emphasis on reliability, efficiency, and automotive-grade quality.

The 74HCT238DB,118 belongs to Nexperia's 74HCT logic family, engineered specifically for seamless integration between TTL-based legacy systems and modern CMOS-based controllers in industrial and automotive applications.

FAQ

What is the maximum clock frequency supported by the 74HCT238DB,118?

The 74HCT238DB,118 is a combinational logic device with no internal clock; its usable switching rate is determined by propagation delay and system timing margins. With tpd = 18 ns (typ) and tt = 7 ns (typ), it reliably supports address/data transitions up to approximately 25 MHz in well-designed PCB layouts with proper decoupling and termination.

Can the 74HCT238DB,118 be used as a demultiplexer?

Yes: configure one enable input (e.g., E3) as the data input, and use the remaining enables (E1, E2) and address lines (A0–A2) as select/strobe controls. When E1 and E2 are held LOW and E3 toggles, the selected Yx output mirrors E3's state-enabling true 1-to-8 demultiplexing without additional gates.

Is the 74HCT238DB,118 qualified for automotive applications?

No: although rated for -40 °C to +125 °C, the 74HCT238DB,118 is not AEC-Q100 qualified. Nexperia explicitly states non-automotive qualification unless expressly noted; for automotive ECUs, use the pin-compatible AEC-Q100 qualified 74HCT238DP,118 (SO16) or equivalent qualified variant.

What is the recommended decoupling for the 74HCT238DB,118?

A 100 nF X7R ceramic capacitor placed within 5 mm of the VCC (pin 16) and GND (pin 8) pins is mandatory. For systems with high di/dt noise, add a 10 µF tantalum or polymer capacitor near the power entry point. Avoid shared vias between VCC and GND traces to prevent ground bounce during simultaneous output switching.