Renesas 74HCT138FP-E

Overview

74HCT138FP-E from Renesas Electronics is a 3-to-8-line decoder/demultiplexer with active-low outputs, three binary select inputs (A, B, C), and three enable terminals (G1 high-active, G2A/G2B low-active). It operates at VCC = 4.5–5.5 V, delivers tPLH/tPHL ≤ 38 ns over –40°C to +85°C, and drives up to 10 LSTTL loads. It is used in address decoding for microcontroller-based memory systems and I/O port expansion.

For engineers reviewing the 74HCT138FP-E datasheet, 74HCT138FP-E pinout, 74HCT138FP-E application, or 74HCT138FP-E equivalent, this page provides verified functional specifications, validated SOP-16 pin mapping, confirmed operating voltage and timing limits, and two industry-validated alternative parts for design continuity.

Technical Context

The 74HCT138FP-E implements standard TTL-compatible HCT logic with CMOS input structure, enabling direct interfacing with both 5 V TTL and CMOS systems. Its three enable inputs allow hierarchical cascading of multiple decoders without external gating logic.

Each of the eight outputs is active-low and fully buffered, supporting fanout of 10 LSTTL loads. Propagation delay is specified under CL = 50 pF and input rise/fall times ≤ 6 ns, with guaranteed performance across industrial temperature range (–40°C to +85°C).

Key Specifications

Pinout & Package

SOP-16 (JEITA PRSP0016DH-B, Renesas code FP-16DAV), 5.5 mm × 10.06 mm body, 1.27 mm pitch, Ni/Pd/Au-plated leads, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HCT138DR, the 74HCT138FP-E offers identical timing and interface behavior with Renesas-specific quality validation for industrial temperature operation; versus 74VHC138M, it trades speed for robust 5 V TTL interoperability and higher noise immunity in noisy control environments.

Availability

74HCT138FP-E is available at Aetrix Electronics and suitable for memory address decoding, I/O port expansion, LED segment selection, and interrupt prioritization requiring stable component supply across industrial temperature ranges and long-term production cycles.

Supply support for 74HCT138FP-E 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

Renesas Electronics Corporation is a global semiconductor leader specializing in microcontrollers, analog, power, and timing solutions for industrial, automotive, and infrastructure markets.

The HD74HCT series delivers TTL-compatible high-speed CMOS logic optimized for robust 5 V system integration, targeting cost-sensitive industrial control, instrumentation, and legacy-compatible embedded designs.

FAQ

What is the maximum operating temperature range for the 74HCT138FP-E?

The 74HCT138FP-E is rated for continuous operation from –40°C to +85°C, with all electrical characteristics fully guaranteed across this industrial temperature range. This includes propagation delay, output drive strength, and input threshold voltages - no derating is required at either extreme. The 74HCT138FP-E achieves this using Renesas' standard-grade process qualified for computers, office equipment, and industrial robots per their quality classification documentation.

Does the 74HCT138FP-E support 3.3 V logic input levels?

No, the 74HCT138FP-E does not reliably recognize 3.3 V as a valid high-level input. Its VIH minimum is 2.0 V at VCC = 4.5–5.5 V, but this specification assumes VCC ≥ 4.5 V and is not tested at lower supply voltages. When driven by 3.3 V logic, the 74HCT138FP-E may exhibit marginal or inconsistent switching due to insufficient noise margin - use level-shifting circuitry or select a 74VHC138 variant if interfacing with 3.3 V systems.

Can the 74HCT138FP-E be used in cascaded decoder configurations?

Yes, the 74HCT138FP-E is explicitly designed for cascading via its three enable inputs: G1 (active-high), G2A and G2B (both active-low). For example, two devices can decode 4-bit addresses into 16 outputs by connecting the fourth bit to G1 of the second decoder while tying G2A/G2B low and using the first decoder's Y0–Y1 outputs to enable each half. The 74HCT138FP-E's enable propagation delay (≤38 ns) ensures synchronous selection across stages without added timing uncertainty.

What is the output drive capability of the 74HCT138FP-E at VCC = 5.0 V?

At VCC = 5.0 V and Ta = 25°C, the 74HCT138FP-E guarantees VOL ≤ 0.26 V at IOL = 4 mA and VOH ≥ 4.18 V at IOH = –4 mA. Over the full industrial temperature range (–40°C to +85°C), these values degrade to VOL ≤ 0.33 V and VOH ≥ 4.13 V. This allows direct driving of LSTTL inputs or LEDs with appropriate current limiting, and supports fanout of up to 10 standard TTL loads per output.

Is the 74HCT138FP-E RoHS compliant and lead-free?

Yes, the 74HCT138FP-E uses Ni/Pd/Au-plated leads and conforms to the EU RoHS Directive, as confirmed by Renesas' package documentation (PRSP0016DH-B) and material declarations. The device contains no lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE above threshold limits. RoHS compliance is maintained across all manufacturing lots, and full substance disclosure reports are available through Renesas' environmental portal upon request.