Diodes Incorporated 74AHC138T16-13

Overview

74AHC138T16-13 from Diodes Incorporated is a 3-to-8 line decoder/demultiplexer in TSSOP-16 package, accepting three binary address inputs (A0–A2) and three enable inputs (E1, E2 active-low; E3 active-high) to drive one of eight active-low outputs (Y0–Y7). It operates from 2.0 V to 5.5 V, sinks/sources up to 8 mA at 4.5 V, and features Schmitt-trigger inputs for noise immunity. Used for memory chip select decoding and peripheral demultiplexing in microcontroller-based control systems.

For engineers reviewing the 74AHC138T16-13 datasheet, 74AHC138T16-13 pinout, 74AHC138T16-13 application, or 74AHC138T16-13 equivalent, key selection criteria include enable logic configuration (dual active-low + single active-high), output drive capability at 3.3 V/5 V, propagation delay under 7 ns (VCC = 4.5–5.5 V, CL = 15 pF), and TSSOP-16 thermal and board-space advantages over SOIC.

Technical Context

The 74AHC138T16-13 implements combinational logic decoding with strict enable hierarchy: all outputs go high unless E1 = LOW, E2 = LOW, and E3 = HIGH. Its internal architecture uses NAND-based gates with buffered outputs and Schmitt-trigger inputs on all address and enable pins, enabling reliable operation with slow or noisy input signals.

It supports cascading via enable lines-E1/E2/E3 allow parallel expansion to 4-to-16 or 5-to-32 decoders without external logic. The device exhibits rail-to-rail input tolerance (up to 5.5 V) and maintains CMOS-compatible voltage thresholds across its full 2.0–5.5 V supply range, ensuring interoperability with mixed-voltage digital systems.

Key Specifications

Pinout & Package

TSSOP-16 package: 4.9 mm × 6.4 mm body, 0.65 mm pitch, 1.08 mm max height, lead-free and RoHS-compliant, optimized for high-density PCB layouts with improved thermal dissipation vs. SOIC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC138PWR and 74LVC138PW,118, the 74AHC138T16-13 uniquely balances 2.0–5.5 V operation, Schmitt noise immunity, and TSSOP-16 density-making it optimal for mixed-voltage industrial controllers where reliability and footprint matter more than ultra-low voltage support.

Availability

74AHC138T16-13 is available at Aetrix Electronics and suitable for memory chip select decoding, microcontroller peripheral demultiplexing, and industrial I/O expansion requiring stable component supply, consistent TSSOP-16 sourcing, and long-term industrial temperature support.

Supply support for 74AHC138T16-13 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, industry-qualified components for automotive, industrial, and computing markets.

The 74AHC logic family targets high-speed, low-power, mixed-voltage digital interface applications-designed specifically for robust operation across wide temperature ranges and noisy environments in embedded control systems.

FAQ

What are the exact enable logic requirements to activate a single output?

All three enable inputs must satisfy: E1 = LOW, E2 = LOW, and E3 = HIGH. Only then does the device decode A0–A2 to assert exactly one of Y0–Y7 as LOW; all other outputs remain HIGH. If any enable condition fails, all outputs go HIGH regardless of address inputs.

Can the 74AHC138T16-13 drive LEDs directly?

Yes-it can sink up to 8 mA per output at VCC = 4.5 V, sufficient for low-current indicator LEDs (e.g., 1–2 mA with 2.2 kΩ series resistor). For higher-current loads (>8 mA), an external transistor or buffer is required to avoid exceeding absolute maximum ratings.

Is the TSSOP-16 package pin-compatible with the SO-16 version?

No-while both packages have identical pin numbering and logic function, TSSOP-16 has 0.65 mm pitch and 4.9 mm × 6.4 mm body, whereas SO-16 uses 1.27 mm pitch and 10 mm × 4 mm body. PCB footprints and reflow profiles are not interchangeable; separate layout files are required.

Does this device support hot-swap or live-insertion?

Not recommended-although inputs tolerate up to 5.5 V independent of VCC, the device lacks power-on reset or Ioff protection. Applying inputs before VCC stabilization may cause latch-up or undefined output states. Always sequence VCC before signal application in hot-swap systems.