Texas Instruments CD74ACT138M96

Overview

CD74ACT138M96 from Texas Instruments is a high-speed 3-line-to-8-line decoder/demultiplexer in SOIC-16 package, operating at 4.5–5.5 V with propagation delays as low as 2.6 ns (G2A/G2B to Y), ±24 mA output drive, and TTL-compatible inputs. It serves as a memory address decoder or data router in high-performance embedded control and industrial logic systems.

For engineers reviewing the CD74ACT138M96 datasheet, CD74ACT138M96 pinout, CD74ACT138M96 application, or CD74ACT138M96 equivalent, key selection criteria include its triple enable architecture (G1, G2A, G2B), balanced tPLH/tPHL timing, SCR-latchup-resistant CMOS process, and compatibility with fast-enable memory subsystems requiring sub-12 ns decoding latency.

Technical Context

The CD74ACT138M96 implements positive-logic decoding with three binary select inputs (A, B, C) and three independent enables: one active-high (G1) and two active-low (G2A, G2B). This configuration enables cascading without external inverters - e.g., a 24-line decoder uses only two devices, while a 32-line implementation requires just one inverter.

Its switching behavior is characterized by matched tPLH/tPHL (≤10.9 ns max over –40°C to 85°C), guaranteed fanout to 15 F-family devices, and ESD robustness exceeding 2 kV HBM. The device operates across –55°C to 125°C, with quiescent ICC ≤ 80 μA at 5.5 V and input transition rate tolerance of 10 ns/V.

Key Specifications

Pinout & Package

CD74ACT138M96 is packaged in a 16-pin SOIC (D package), body size 9.9 mm × 3.9 mm, with standard 1.27 mm pitch and gull-wing leads. Thermal resistance RθJA = 106.6°C/W enables operation at full speed without forced airflow in compact PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ACT138N and CD74HC138E, the CD74ACT138M96 uniquely delivers military-grade temperature range, TTL input compatibility, and ±24 mA drive in a production-ready SOIC tape-and-reel format - making it the sole choice for high-reliability, high-speed decoding where timing margin and ruggedness are non-negotiable.

Availability

CD74ACT138M96 is available at Aetrix Electronics and suitable for industrial PLCs, automotive body controllers, high-speed memory subsystems, and test equipment requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for CD74ACT138M96 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 specializing in analog, embedded processing, and logic solutions, with decades of heritage in high-reliability logic families and automotive-qualified components.

The CD74ACT138M96 belongs to TI's advanced CMOS (ACT) logic family, engineered for high-speed memory decoding and data-routing applications demanding low propagation delay, robust noise immunity, and extended temperature operation.

FAQ

What is the maximum operating frequency supported by the CD74ACT138M96?

The CD74ACT138M96 does not specify a maximum clock frequency because it is a combinational logic device without internal clocking. Its usable speed is determined by propagation delay: worst-case tPLH/tPHL is 10.9 ns over –40°C to 85°C, supporting reliable operation in address decode paths with >10 MHz toggle rates when paired with appropriate setup/hold margins. The CD74ACT138M96 achieves this using ACT-series bipolar-CMOS hybrid design.

Does the CD74ACT138M96 require external pull-up resistors on its outputs?

No, the CD74ACT138M96 features totem-pole CMOS outputs capable of actively driving HIGH or LOW without external pull-ups. Its outputs are specified for ±24 mA drive into resistive or capacitive loads, and the Y0–Y7 pins are active-low - meaning they sink current when asserted. External pull-ups would conflict with output drive capability and are unnecessary for standard interfacing. The CD74ACT138M96 is designed for direct connection to downstream logic inputs.

Can the CD74ACT138M96 be used as a demultiplexer?

Yes, the CD74ACT138M96 functions as a 1-to-8 demultiplexer when one enable input (e.g., G1) is used as the data input and the remaining enables (G2A, G2B) plus select lines (A, B, C) configure routing. Per the datasheet's Application Information section, this mode allows serial data distribution across eight channels with minimal external logic. The CD74ACT138M96 maintains identical timing and drive specs in demux mode as in decode mode.

What is the recommended bypass capacitor for the CD74ACT138M96?

Texas Instruments recommends a 0.1 μF ceramic capacitor placed as close as possible to the VCC pin of the CD74ACT138M96, with short, low-inductance traces to GND. For enhanced high-frequency noise suppression, a parallel 1 μF capacitor may be added. This bypassing strategy minimizes supply rail disturbance during rapid output transitions and ensures stable operation at maximum switching speeds. The CD74ACT138M96's dynamic current demands make localized decoupling essential.

Is the CD74ACT138M96 pin-compatible with other 138-series decoders like the 74LS138?

No, the CD74ACT138M96 is not pin-compatible with bipolar 74LS138 due to differing electrical characteristics - though both share identical SOIC-16 pinout geometry. The CD74ACT138M96 has CMOS inputs (TTL-compatible thresholds) and higher drive strength (±24 mA vs. ±8 mA), while the 74LS138 uses LS-TTL inputs and outputs. Swapping them requires verifying voltage levels, loading, and timing margins; the CD74ACT138M96 cannot be treated as a drop-in replacement without system-level validation.