Onsemi MC14584BD Hex Schmitt Trigger IC: Datasheet, Application Circuit, and Pinout Configuration

The Onsemi MC14584BD is a highly reliable integrated circuit belonging to the 4000 series CMOS logic family. It incorporates six independent Schmitt trigger inverters in a single 14-pin package. This device is specifically engineered to convert slowly changing or noisy input signals into clean, sharp digital output waveforms with fast rise and fall times. Its inherent hysteresis makes it exceptionally useful for debouncing switches, conditioning sensor outputs, and creating simple oscillators.

Pinout Configuration

The pinout of the MC14584BD is logically arranged for ease of use on a printed circuit board (PCB). The IC is supplied in a standard PDIP-14 package.

Pins 1, 3, 5, 9, 11, 13: These are the inputs for the six individual Schmitt trigger inverters.

Pins 2, 4, 6, 8, 10, 12: These are the corresponding outputs for each inverter.

Pin 7 (Vss): This is the ground (GND) pin, the negative supply terminal.

Pin 14 (Vdd): This is the positive power supply pin, which typically operates from 3V to 18V, offering great flexibility in interfacing with various logic levels.

Datasheet Overview

The manufacturer's datasheet is the ultimate source of information for designing with this IC. Key parameters detailed include:

Supply Voltage Range (Vdd): 3.0 V to 18.0 V

High-Level Input Voltage (VIH): Minimum of 70% Vdd at Vdd=10V.

Low-Level Input Voltage (VIL): Maximum of 30% Vdd at Vdd=10V.

Hysteresis (ΔVT): A critical Schmitt trigger characteristic. The typical hysteresis voltage is 0.9 V at Vdd = 5.0 V and 2.3 V at Vdd = 10.0 V.

Maximum Clock Frequency: Typically 8 MHz at 10V.

Power Consumption: Very low static power consumption, a hallmark of CMOS technology.

Application Circuit

One of the most common applications for the MC14584BD is signal conditioning. For instance, a simple circuit for debouncing a mechanical pushbutton switch can be constructed using just one of the six inverters.

1. The pushbutton is connected between Vdd and the input of one inverter (e.g., Pin 1).

2. A pull-down resistor (e.g., 10kΩ) is connected between the same input (Pin 1) and Vss (GND).

3. The output (Pin 2) provides a clean, bounce-free digital signal that can be fed directly into a microcontroller or other digital logic.

Another fundamental application is building a simple RC oscillator. By connecting a resistor (R) between the output and input of an inverter and a capacitor (C) from the input to ground, the circuit will oscillate. The hysteresis of the Schmitt trigger determines the charging thresholds of the capacitor, creating a stable square wave with a frequency roughly defined by f ≈ 1 / (0.8 RC).

ICGOODFIND: The Onsemi MC14584BD stands as a versatile and robust solution for managing imperfect digital signals. Its built-in hysteresis provides superior noise immunity, making it indispensable for debouncing switches and squaring up analog waveforms. The wide operating voltage range ensures compatibility with a vast array of systems, from vintage 5V TTL to higher voltage industrial controls. For any designer needing signal cleanup or simple clock generation, this hex Schmitt trigger IC is a fundamental and highly effective component.

Keywords: Schmitt Trigger, Signal Conditioning, Debounce Circuit, CMOS Logic, Hysteresis