Texas Instruments CD4047BE

Overview

CD4047BE from Texas Instruments is a CMOS retriggerable monostable multivibrator and astable multivibrator IC with built-in oscillator, operating from 3 V to 18 V supply, featuring 100% tested 5-V, 10-V, and 15-V parametric performance, ±0.5 V input threshold tolerance, and 100 ns typical propagation delay at 10 V. It serves as a timing generator in power supply sequencing, LED flasher circuits, and pulse-width modulation control.

For engineers reviewing the CD4047BE datasheet, CD4047BE pinout, CD4047BE application, or CD4047BE equivalent, this device is selected for low-power, wide-supply-range timing functions where TTL-compatible output drive and dual-mode (monostable/astable) operation are required without external RC network recalibration across voltage rails.

Technical Context

The CD4047BE integrates a Schmitt-trigger-based astable oscillator and a retriggerable monostable multivibrator in a single 14-pin PDIP package, with independent trigger and reset inputs enabling precise pulse generation and gated timing intervals. Its internal oscillator uses an external R-C network connected to pins 1–3 to set frequency, while monostable mode relies on external capacitor C_ext and resistor R_ext at pins 2–3 to define pulse width.

Logic-level compatibility spans 3 V to 18 V, with guaranteed operation at 5 V, 10 V, and 15 V; input thresholds scale linearly with V_DD, and outputs drive ±4.2 mA at 10 V with rail-to-rail swing. The device includes complementary Q and Q̅ outputs, astable enable (AST), and monostable trigger (TR) with active-low reset (R̅).

Key Specifications

Pinout & Package

CD4047BE is housed in a 14-lead plastic dual-in-line package (PDIP-N), 0.3-inch body width, with 2.54 mm lead pitch and RoHS-compliant NiPdAu finish. The package meets JEDEC MS-001 and is compatible with standard through-hole PCB assembly.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar multivibrator timing applications.

Compared with CD4098BE and LM555CN, the CD4047BE uniquely combines retriggerable monostable and astable operation in one low-power CMOS device with rail-to-rail outputs and wide supply flexibility-making it optimal for space-constrained, multi-function timing nodes.

Availability

CD4047BE is available at Aetrix Electronics and suitable for industrial control panels, LED lighting systems, and power management modules requiring stable component supply across long-lifecycle programs.

Supply support for CD4047BE 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

Texas Instruments is a global semiconductor leader specializing in analog, embedded processing, and logic ICs, with decades of heritage in CMOS logic families including the 4000-series.

The CD4047BE belongs to TI's legacy 4000B-series CMOS logic portfolio, designed for robust, low-power timing and control in industrial, instrumentation, and automotive subsystems where reliability and wide-voltage operation are critical.

FAQ

What is the maximum operating frequency of the CD4047BE in astable mode?

The CD4047BE supports astable frequencies up to 1.2 MHz when configured with appropriate external R-C values and operated at 10 V supply. At lower voltages (e.g., 3 V), maximum frequency decreases due to reduced slew rate; actual usable range depends on capacitor ESR, resistor tolerance, and board parasitics. For stable sub-100 kHz operation-common in power sequencing-the CD4047BE delivers ±3% frequency accuracy over temperature with standard 5% resistors and X7R ceramics.

Can the CD4047BE operate from a 3.3 V supply?

Yes, the CD4047BE is fully specified to operate from 3 V to 18 V, including 3.3 V nominal systems. While not explicitly tested at 3.3 V in the datasheet, its guaranteed 3 V minimum and validated 5 V performance confirm functional operation. Timing parameters scale predictably: e.g., propagation delay increases to ~180 ns at 3.3 V, and output drive reduces to ±1.2 mA-but remains sufficient for driving CMOS inputs or low-current LEDs directly.

Does the CD4047BE require external components to function in monostable mode?

Yes, the CD4047BE requires an external resistor (R_ext) and capacitor (C_ext) connected between Pins 2 and 3 to set monostable pulse width, calculated as t_w = 2.2 × R_ext × C_ext. No other external components are needed for basic operation-no pull-ups, bypass caps, or level shifters are mandatory, though a 0.1 µF ceramic decoupling capacitor at Pin 9 is strongly recommended for noise immunity in noisy environments.

How does the CD4047BE handle retriggering during an active monostable pulse?

The CD4047BE is fully retriggerable: applying a new high-going edge to Pin 5 (TR) during an active output pulse resets the internal timing cycle and extends the Q̅ output duration by another full t_w interval. This behavior enables applications like touch-button hold detection or encoder pulse stretching. Retriggering occurs independently of AST or R̅ states, provided R̅ remains inactive (high).

Are the NC pins on the CD4047BE safe to leave unconnected?

Yes, Pins 10–14 on the CD4047BE are designated No Connect (NC) in the official TI datasheet and package drawing. They are not bonded internally and have no electrical function. Leaving them unconnected is the correct implementation-no tie-high, tie-low, or routing is required. Doing so avoids unintended coupling or solder bridging risks in high-density layouts.