STMicroelectronics 74VHC138MTR

Overview

74VHC138MTR from STMicroelectronics is a high-speed CMOS 3-to-8 line decoder with inverting outputs, operating from 2V to 5.5V supply, featuring 5.7ns typical propagation delay at 5V, ±8mA symmetrical output drive, and 4µA max quiescent current at 25°C. It implements address decoding in memory systems using three binary inputs (A/B/C) and three enable inputs (G1, G2A, G2B), with all outputs active-low.

For engineers reviewing the 74VHC138MTR datasheet, 74VHC138MTR pinout, 74VHC138MTR application, or 74VHC138MTR equivalent, key selection criteria include its 2V–5.5V wide VCC range, input overvoltage tolerance up to 7V, ESD immunity of 2kV, latch-up immunity, and compatibility with legacy 74-series logic timing and pinout.

Technical Context

The device uses sub-micron silicon gate C2MOS technology to achieve balanced tPLH/tPHL delays and low power consumption. Its enable architecture-requiring G1 HIGH and both G2A/G2B LOW for decode activation-supports cascaded memory address decoding without external gating.

All inputs feature power-down protection and accept 0–7V regardless of VCC, enabling robust 5V-to-3V interfacing. Outputs are fully buffered with symmetrical |IOH| = IOL ≥ 8mA, supporting direct fan-out to multiple TTL or CMOS loads under defined VCC and temperature conditions.

Key Specifications

Pinout & Package

SOP-16 (Small Outline Package, 150mil width), RoHS-compliant, tape-and-reel packaged as indicated by "MTR" suffix.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74HC138DR and 74LVC138PW,118, the 74VHC138MTR uniquely combines 7V input tolerance, 4µA quiescent current, and full 2V–5.5V operation - making it the only option qualified for mixed-rail, high-reliability, and legacy-upgrade applications without redesign.

Availability

74VHC138MTR is available at Aetrix Electronics and suitable for memory address decoding, peripheral select logic, bus interface translation, and legacy system upgrades requiring stable component supply across industrial temperature ranges and long-lifecycle programs.

Supply support for 74VHC138MTR 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, designing and manufacturing analog, digital, and mixed-signal ICs for automotive, industrial, and consumer markets.

The 74VHC logic family targets high-speed, low-power, and robust interface solutions for industrial control, embedded computing, and legacy system modernization - emphasizing voltage flexibility, ESD resilience, and long-term supply stability.

FAQ

What is the maximum operating temperature range for the 74VHC138MTR?

The 74VHC138MTR is specified for continuous operation from –55°C to +125°C, validated per STMicroelectronics' industrial-grade qualification standards. This range covers extended-temperature applications such as motor control enclosures, outdoor telecom infrastructure, and under-hood automotive modules where ambient heat exceeds commercial limits.

Can the 74VHC138MTR safely interface a 5V microcontroller with a 3.3V FPGA?

Yes - its inputs tolerate 0–7V regardless of VCC, and its outputs swing rail-to-rail (0V to VCC). When powered at 3.3V, it accepts 5V address/control signals directly without clamping diodes, and delivers clean 0V/3.3V outputs compatible with FPGA I/O banks configured for 3.3V LVTTL.

Does the 74VHC138MTR support cascading for larger decode trees?

Yes - the three enable inputs (G1, G2A, G2B) are specifically designed for hierarchical expansion. For example, two 74VHC138MTRs can decode 4-bit addresses into 16 outputs by using the fourth bit to control G1 of each device, while sharing A/B/C and G2A/G2B lines - matching standard memory decoder topologies.

Is the SOP-16 package of the 74VHC138MTR RoHS-compliant and lead-free?

Yes - the "MTR" suffix denotes STMicroelectronics' standard RoHS-compliant, lead-free, halogen-free SOP-16 package, qualified to JEDEC J-STD-020 moisture sensitivity level 3 (MSL3) and compliant with EU Directive 2011/65/EU. Full material declarations and test reports are available upon request for compliance verification.