STMicroelectronics M74HC42RM13TR

Overview

M74HC42RM13TR from STMicroelectronics is a high-speed CMOS BCD-to-decimal decoder in TSSOP-16 package, operating from 2V to 6V supply, with typical propagation delay of 14ns at 6V, symmetrical output drive (±4mA), and guaranteed noise immunity (28% VCC). It decodes four BCD inputs (A–D) to activate one of ten active-low decimal outputs (Y0–Y9), used in address decoding and memory selection for industrial control panels.

For engineers reviewing the M74HC42RM13TR datasheet, M74HC42RM13TR pinout, M74HC42RM13TR application, or M74HC42RM13TR equivalent, key selection criteria include its 10-output active-low decoding logic, wide VCC range, low ICC (4µA max), TSSOP-16 footprint compatibility with legacy 74-series layouts, and operation across –55°C to +125°C.

Technical Context

This device implements combinational BCD-to-decimal decoding using silicon gate C2MOS technology, with all inputs protected against ESD and transient overvoltage. Its logic function maps binary-coded decimal inputs (0000–1001) to ten mutually exclusive active-low outputs; invalid codes (1010–1111) yield all-high outputs.

Propagation delays are balanced (tPLH ≈ tPHL), output impedance is symmetrical (|IOH| = IOL ≥ 4mA), and input thresholds scale with VCC (VIH = 0.7×VCC min, VIL = 0.3×VCC max), enabling robust interfacing across voltage domains without level shifters.

Key Specifications

Pinout & Package

TSSOP-16 package: 4.9 × 6.4 mm body, 0.65 mm pitch, exposed pad not present, JEDEC MO-153 compliant.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar BCD-to-decimal decoder applications.

Compared with SN74HC42DR and 74LV42PW,118, the M74HC42RM13TR uniquely supports full –55°C to +125°C operation in TSSOP-16 while maintaining 74-series pinout compatibility and 2–6V flexibility - making it optimal for ruggedized, mixed-voltage, space-constrained applications.

Availability

M74HC42RM13TR is available at Aetrix Electronics and suitable for industrial PLCs, legacy instrumentation upgrades, and memory selection circuits requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for M74HC42RM13TR 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 microcontrollers, power ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The M74HC42 belongs to ST's high-speed CMOS logic family, engineered for pin-compatible migration from obsolete 74LS devices while delivering lower power, wider voltage range, and enhanced noise immunity in modern control systems.

FAQ

What is the maximum output sink current specification for M74HC42RM13TR?

The device guarantees IOL ≥ 4mA per output at VCC = 4.5V and TA = 25°C, with VOL ≤ 0.26V. At VCC = 6.0V, it delivers ≥5.2mA with VOL ≤ 0.26V. These values ensure reliable driving of TTL loads or multiple 74HC inputs without external buffers.

Does M74HC42RM13TR support 3.3V-only operation?

Yes - it operates fully across 2V to 6V, including 3.3V nominal systems. At VCC = 3.3V, VIH is 2.31V min and VIL is 0.99V max, providing 0.6V noise margin. Propagation delay increases to ~20ns (typ), remaining suitable for most 3.3V microcontroller interfaces.

Can unused inputs be left floating?

No - all inputs (A–D) lack internal pull-up/down resistors. Floating inputs cause unpredictable output states and increased ICC due to input stage contention. Unused inputs must be tied to VCC or GND via ≤10kΩ resistors to ensure deterministic logic behavior and low power consumption.

Is M74HC42RM13TR RoHS compliant and halogen-free?

Yes - manufactured per STMicroelectronics' ECOPACK2 specifications: lead-free, RoHS-compliant, and halogen-free (Br < 900 ppm, Cl < 900 ppm, total halogens < 1500 ppm), with full material declarations available in ST's official product change notices.