Diodes Incorporated 74AHC138S16-13

Overview

74AHC138S16-13 from Diodes Incorporated is a 3-to-8 line decoder/demultiplexer in SO-16 package, operating from 2.0 V to 5.5 V supply, with three binary address inputs (A0–A2), three enable inputs (E1, E2 active-low; E3 active-high), and eight active-low outputs (Y0–Y7). It enables memory chip select decoding and serial-to-parallel peripheral control in microcontroller-based systems.

For engineers reviewing the 74AHC138S16-13 datasheet, 74AHC138S16-13 pinout, 74AHC138S16-13 application, or 74AHC138S16-13 equivalent, key selection criteria include enable logic configuration (E1/E2 low + E3 high), output drive capability (8 mA sink at 4.5 V), propagation delay (3.0 ns typ. at 5 V, CL = 15 pF), Schmitt-trigger inputs for noise immunity, and SO-16 thermal performance up to +125°C ambient.

Technical Context

The 74AHC138S16-13 implements a fully decoded 3-bit binary input path with active-low output assertion, where only one of eight outputs goes low per valid address/enable combination. Its triple-enable architecture (two active-low, one active-high) supports hierarchical expansion-e.g., cascading two units with an inverter yields a 4-to-16 decoder without external logic gates.

Input stages integrate Schmitt-trigger action across all address and enable pins, ensuring robust noise rejection and consistent switching thresholds independent of rise/fall time. Output stage design delivers symmetrical sourcing/sinking capability (±8 mA at VCC = 4.5 V) and guarantees VOL ≤ 0.36 V at IOL = 4 mA (3.0 V operation), supporting TTL- and CMOS-compatible interfacing.

Key Specifications

Pinout & Package

74AHC138S16-13 is housed in a 16-pin Small Outline Integrated Circuit (SO-16) package with 1.27 mm pitch, JEDEC MS-012AC compliant, and RoHS-compliant lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74AHCT138DR and 74LVC138AD,118, the 74AHC138S16-13 uniquely balances wide-voltage operation (2.0–5.5 V), Schmitt-trigger noise immunity, and industrial temperature support-making it optimal for ruggedized embedded controllers where supply rail flexibility and EMI resilience are non-negotiable.

Availability

74AHC138S16-13 is available at Aetrix Electronics and suitable for memory decoding, microcontroller peripheral control, and industrial I/O expansion requiring stable component supply across automotive-grade temperature ranges and long-lifecycle production programs.

Supply support for 74AHC138S16-13 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and analog ICs, specializing in high-reliability components for industrial, computing, and consumer applications.

The 74AHC logic family targets high-speed, low-power digital interface and decoding functions in mixed-voltage embedded systems, emphasizing robustness, wide operating margins, and environmental compliance.

FAQ

What is the maximum clock frequency supported by the 74AHC138S16-13 for reliable address decoding?

The 74AHC138S16-13 does not operate on a clock signal-it is combinatorial logic. Its propagation delay is 3.0 ns typical (5 V, CL = 15 pF), allowing reliable use in systems with address setup/hold times ≥5 ns. Maximum effective switching rate depends on load capacitance and drive strength, not internal clocking.

Can the 74AHC138S16-13 be used with a 3.3 V microcontroller driving 5 V peripherals?

Yes. With VCC = 5 V, its inputs accept up to 5.5 V and are 5 V tolerant, while its outputs swing rail-to-rail. A 3.3 V MCU can directly drive A0–A2 and E1–E3 if those signals remain within VIH/VIL specs (e.g., VIH ≥ 3.85 V at VCC = 5.5 V requires level-shifting; at VCC = 5.0 V, VIH = 3.85 V still exceeds 3.3 V logic high-so external translation is needed for guaranteed compatibility).

Why does the 74AHC138S16-13 have three enable inputs instead of one?

The three enable inputs (E1, E2 active-low; E3 active-high) implement a flexible 3-input AND gate that allows hierarchical decoder expansion. For example, connecting E1/E2 of multiple 74AHC138S16-13 units to a common bus and using E3 for local selection enables building larger decoders (e.g., 4-to-16) without adding discrete gates-reducing component count and layout complexity.

Is the SO-16 package of the 74AHC138S16-13 compatible with standard PCB footprints for 74-series logic?

Yes. The SO-16 package (S16 suffix) matches JEDEC MS-012AC dimensions: 10.0 mm × 3.9 mm body, 1.27 mm pitch, and 1.75 mm height. It shares footprint compatibility with industry-standard 74AHC, 74HC, and 74LS SO-16 devices, enabling drop-in replacement in existing layouts without redesign.