Texas Instruments CD74HCT138M96

Overview

CD74HCT138M96 from Texas Instruments is a high-speed CMOS 3-to-8 line decoder/demultiplexer with active-low outputs, designed for memory address decoding and data routing in industrial and embedded systems. It operates at 4.5 V to 5.5 V, delivers 14 ns typical propagation delay (V_CC = 4.5 V, C_L = 50 pF), supports -55°C to +125°C operation, and features three enable inputs (G2, G1, G0) for cascading.

For engineers reviewing the CD74HCT138M96 datasheet, CD74HCT138M96 pinout, CD74HCT138M96 application, or CD74HCT138M96 equivalent, this page provides verified functional modes, true output polarity behavior (Y0–Y7 active low when selected), thermal performance (R_θJA = 73°C/W), LSTTL-compatible input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V), and SOIC-16 package mechanical data.

Technical Context

The CD74HCT138M96 implements a standard 3:8 binary decoder with three address inputs (A0–A2) and eight complementary outputs (Y0–Y7). Its logic function is fully defined by the '138 family's truth table: outputs go low only when all three strobes are asserted (G2 = H, G1 = L, G0 = L) and a unique 3-bit address is applied - otherwise all outputs remain high.

It uses silicon-gate CMOS technology with TTL-compatible input thresholds and rail-to-rail output swing. The device supports demultiplexing via strobe-as-data configuration and enables hierarchical decoding through G0/G1/G2 gating - critical for multi-bank memory or peripheral selection in microcontroller-based designs.

Key Specifications

Pinout & Package

CD74HCT138M96 is housed in a 16-pin SOIC (D) package measuring 9.90 mm × 3.90 mm, with standard JEDEC MS-012AC outline and 1.27 mm pitch. Pin 1 is marked with a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT138DR and 74HCT138D,653, the CD74HCT138M96 offers guaranteed -55°C to +125°C operation and TI-specific quality screening - making it the preferred choice for aerospace, defense, and high-reliability industrial control systems where environmental robustness is non-negotiable.

Availability

CD74HCT138M96 is available at Aetrix Electronics and suitable for memory address decoding, peripheral selection in MCU systems, LED display multiplexing, and industrial I/O expansion requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74HCT138M96 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, embedded processing, and connectivity solutions for industrial, automotive, and personal electronics markets.

CD74HCT138M96 belongs to TI's legacy high-speed CMOS logic portfolio, engineered specifically for robust, low-power, TTL-compatible decoding in mission-critical embedded systems where reliability across extreme temperatures is essential.

FAQ

What is the output polarity of CD74HCT138M96?

The CD74HCT138M96 features active-low outputs: when a valid address (A2–A0) is applied and all enable inputs are asserted (G2 = H, G1 = L, G0 = L), exactly one of Y0–Y7 goes low while all others remain high. This behavior is fixed and cannot be configured - it distinguishes CD74HCT138M96 from the '238 variant, which has active-high outputs.

Can CD74HCT138M96 operate at 3.3 V?

No, CD74HCT138M96 is specified only for 4.5 V to 5.5 V operation. Its TTL-compatible input thresholds (V_IL ≤ 0.8 V, V_IH ≥ 2.0 V) and internal circuitry require minimum 4.5 V to guarantee correct logic levels and timing. For 3.3 V systems, consider CD74HC138M96 (2 V to 6 V) instead.

How does the enable logic work on CD74HCT138M96?

CD74HCT138M96 requires G2 = HIGH, G1 = LOW, and G0 = LOW simultaneously for normal decoding. If any enable is violated - e.g., G0 = HIGH - all outputs (Y0–Y7) are forced HIGH regardless of A2–A0 state. This three-input gating enables precise hierarchical control in multi-chip systems.

Is CD74HCT138M96 RoHS compliant?

Yes, CD74HCT138M96 is RoHS compliant with lead finish NIPDAU | SN, per TI's official packaging addendum. It meets EU Directive 2011/65/EU requirements and carries no exemptions - confirmed by TI's material declaration and shipping documentation.

What is the maximum output sink current for CD74HCT138M96?

CD74HCT138M96 guarantees ±4 mA output drive per Yx pin at V_CC = 4.5 V, with VOL ≤ 0.33 V (max) under that load. This supports direct driving of LEDs (with series resistor), small-signal MOSFET gates, or up to 10 LSTTL inputs - consistent across -55°C to +125°C operating range.