STMicroelectronics 74LVQ138MTR

Overview

74LVQ138MTR from STMicroelectronics is a low-voltage CMOS 3-to-8 line decoder (inverting) with TTL-compatible outputs, operating from 2.0 V to 3.6 V, featuring 5.5 ns typical propagation delay at 3.3 V, 12 mA minimum output drive, and 4 µA maximum quiescent current at 25°C. It serves as an address decoder in memory systems and bus interface logic.

For engineers reviewing the 74LVQ138MTR datasheet, 74LVQ138MTR pinout, 74LVQ138MTR application, or 74LVQ138MTR equivalent, key selection criteria include its symmetrical output impedance (|IOH| = IOL = 12 mA), 75 Ω transmission line driving capability, balanced tPLH/tPHL delays, and triple enable inputs (G1, G2A, G2B) for cascaded decoding.

Technical Context

The 74LVQ138MTR implements active-low 3-input binary decoding with three independent enable inputs: G1 (active-high), G2A and G2B (both active-low). When enabled, only one of eight inverted outputs (Y0–Y7) goes low based on A/B/C address inputs; all outputs remain high otherwise.

It uses sub-micron C2MOS technology with ESD protection (2 kV HBM), operates across –55°C to +125°C, and guarantees PCI bus levels at 24 mA sink/source while maintaining low noise (VOLP = 0.2 V typ. at VCC = 3.3 V).

Key Specifications

Pinout & Package

74LVQ138MTR is housed in a 16-pin SOIC (Small Outline Integrated Circuit) package with tape-and-reel packaging (MTR suffix), compliant with JEDEC MS-012 and RoHS standards.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LV138APWR and 74LVC138PW,118, the 74LVQ138MTR delivers the lowest ICC (4 µA max.), best noise performance (VOLP = 0.2 V), and guaranteed 24 mA PCI compliance - making it optimal for power-constrained, noise-sensitive, or legacy bus-critical designs.

Availability

74LVQ138MTR is available at Aetrix Electronics and suitable for memory address decoding, PCI bus interface logic, industrial control backplanes, and low-power embedded systems requiring stable component supply across extended temperature ranges.

Supply support for 74LVQ138MTR 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, Switzerland, specializing in automotive, industrial, and power management ICs with broad analog, digital, and mixed-signal portfolios.

The 74LVQ series targets low-voltage, low-noise 3.3 V logic applications, emphasizing ESD robustness, transmission-line drive, and extended temperature operation for industrial and communications infrastructure.

FAQ

What is the maximum clock frequency supported by the 74LVQ138MTR?

The 74LVQ138MTR is a combinational logic device with no internal clock; its usable frequency depends on propagation delay and system timing margins. With 5.5 ns typical tPD at 3.3 V and balanced tPLH/tPHL, it supports reliable operation in address decode paths up to ~100 MHz bus systems when combined with appropriate setup/hold timing.

Can the 74LVQ138MTR operate at 1.8 V?

No - the 74LVQ138MTR has a specified minimum VCC of 2.0 V per Table 5 (Recommended Operating Conditions). Operation below 2.0 V is not guaranteed and may result in incorrect logic states, increased propagation delay, or failure to meet VIH/VIL thresholds.

Is the 74LVQ138MTR pin-compatible with standard 74HC138 devices?

Yes - the 74LVQ138MTR is pin- and function-compatible with the 74LS138 and 74HC138 families per manufacturer documentation, sharing identical SO-16 pinout, truth table, and enable logic (G1, G2A, G2B), though electrical parameters (VCC range, drive strength, speed) differ.

Does the 74LVQ138MTR require external pull-up resistors on its outputs?

No - outputs are actively driven high or low; Y0–Y7 are push-pull CMOS with 12 mA sink/source capability. Pull-ups are unnecessary unless open-drain emulation or wired-OR logic is specifically required, which contradicts its native inverting push-pull architecture.