CD4047B CMOS Multivibrator Working, and Datasheet Guide

The CD4047B CMOS multivibrator is a widely used timing IC known for its ability to generate accurate pulses and stable square wave signals. This article will discuss the CD4047B basics, pinout details, ordering variants, internal block diagram, specifications, features, working operation, applications, and comparison with CD4047.

Catalog

CD4047B CMOS Multivibrator Basic

The CD4047B is a CMOS multivibrator IC designed for accurate timing and waveform generation. It operates in both astable (free-running) and monostable (one-shot) modes, delivering stable pulse outputs with support for positive and negative edge triggering, including retriggerable operation.

The CD4047B is an improved version of the CD4047, offering better electrical performance, enhanced noise immunity, and wider operating voltage range due to its buffered CMOS design. It also provides more stable timing characteristics and improved reliability compared to the original version.

In astable mode, it produces continuous square waves, while in monostable mode it generates a single pulse based on external RC components. It includes complementary outputs (Q and Q̅), external reset, and trigger inputs for flexible control.

If you are interested in purchasing the CD4047B, feel free to contact us for pricing and availability.

CD4047B CMOS Multivibrator CAD Models

CD4047B CMOS Multivibrator Pinout Details

Pin No.	Pin Name	Description
1	C (Timing Cap)	Connects to external capacitor for timing control
2	R (Timing Resistor)	Connects to external resistor to set timing
3	R-C Common	Common connection point for resistor and capacitor
4	Astable Input	Enables astable (oscillator) mode when HIGH
5	Astable Input	Complementary astable control input
6	-Trigger	Negative edge trigger input for monostable mode
7	VSS (GND)	Ground (0V reference)
8	+Trigger	Positive edge trigger input for monostable mode
9	Ext Reset	External reset input (active HIGH)
10	Q	Normal output
11	Q̅ (Q bar)	Complementary output (inverted)
12	OSC Out	Oscillator output signal
13	Retrigger	Retrigger input for monostable operation
14	VDD	Positive supply voltage

CD4047B Ordering Variants

Part Number	Package Type	Package Code	Pins	Mounting Type	Package Qty	Operating Temp	Notes
CD4047BE	PDIP	N	14	Through Hole	25/tube	-55°C to 125°C	Standard DIP package
CD4047BEE4	PDIP	N	14	Through Hole	25/tube	-55°C to 125°C	Pb-free version
CD4047BM	SOIC	D	14	SMD	50	-55°C to 125°C	Small outline package
CD4047BM96	SOIC	D	14	SMD	2500/reel	-55°C to 125°C	Tape & reel
CD4047BNSR	SOP	NS	14	SMD	2000/reel	-55°C to 125°C	Narrow SOP package
CD4047BPW	TSSOP	PW	14	SMD	90	-55°C to 125°C	Thin package
CD4047BPWR	TSSOP	PW	14	SMD	2000/reel	-55°C to 125°C	Tape & reel
CD4047BF / BF3A	CDIP	J	14	Through Hole	1	-55°C to 125°C	Ceramic (mil/industrial)

Alternatives & Equivalent Model

• HEF4047B

• HCF4047B

• MC14047B

• TC4047B

• CD4047BE

CD4047B Logic Block Diagram

The CD4047B logic block diagram shows how the IC generates timing signals using an internal multivibrator controlled by external components. The R (resistor) and C (capacitor) connected to the timing pins form the RC network, which determines the oscillation frequency or pulse width. These components feed into the low-power astable multivibrator, which is the core of the circuit.

The astable gate control section enables continuous oscillation when the astable inputs are activated. In this mode, the circuit produces a steady square wave that is internally processed by a frequency divider (÷2). This ensures stable and symmetrical output signals at the Q and Q̅ pins.

For single-pulse operation, the monostable control block works with the trigger inputs (+Trigger and −Trigger). When triggered, it generates a precise output pulse based on the RC timing. The retrigger control allows the pulse to be extended if additional trigger signals are received before the cycle completes.

The external reset input can override all operations and force the output to a defined state. Finally, the outputs include the oscillator signal and complementary outputs (Q and Q̅), providing flexible timing and waveform control.

CD4047B CMOS Multivibrator Specifications

Category	Parameter	Value
Absolute Maximum Ratings	Supply Voltage (VDD)	-0.5V to +20V
	Input Voltage Range	-0.5V to VDD + 0.5V
	Input Current (per pin)	±10 mA
	Power Dissipation (PD)	500 mW (≤100°C), derates above
	Output Transistor Dissipation	100 mW
	Operating Temperature	-55°C to +125°C
	Storage Temperature	-65°C to +150°C
	Lead Temperature (Soldering)	+265°C (10s max)
Recommended Operating Conditions	Supply Voltage (VDD)	3V to 18V
	Temperature Note	-25°C to +100°C (at 15V, 10MΩ)
Timing Characteristics	Astable Mode (Q, Q̅)	tA ≈ 4.40 RC
	Astable (OSC Out)	tA ≈ 2.20 RC
	Monostable Mode	tM ≈ 2.48 RC
Package Information	PDIP (CD4047BE)	14-pin plastic DIP
	SOIC (CD4047BM)	14-pin small-outline package
	Ceramic DIP	Hermetic sealed package
	Chip Form	Bare die

CD4047B CMOS Multivibrator Features

Dual Operating Modes (Astable and Monostable)

The CD4047B supports both astable and monostable modes, allowing it to generate continuous square waves or single output pulses. This flexibility makes it suitable for precise timing and control operations using a single IC.

Edge-Triggered Operation

The device can be triggered using either positive (+Trigger) or negative (−Trigger) edge inputs. This enables accurate control of pulse generation based on signal transitions.

Retriggerable Monostable Function

The retrigger input allows the output pulse duration to be extended if additional trigger signals are received before the current cycle ends, improving timing flexibility.

External RC Timing Control

The timing period or frequency is determined by external resistor and capacitor components. This allows easy adjustment of output characteristics based on circuit requirements.

Complementary Outputs (Q and Q̅)

The IC provides both normal (Q) and inverted (Q̅) outputs simultaneously, making it useful for driving complementary circuits without additional components.

Built-in Oscillator with Frequency Divider

An internal oscillator generates signals that are divided by two, ensuring stable and consistent output waveforms with reduced frequency variation.

Wide Operating Voltage Range

The CD4047B operates over a wide supply voltage range (typically 3V to 18V), making it compatible with various digital and analog systems.

External Reset Capability

The external reset input allows the user to quickly reset the output state during operation, providing better control and reliability in timing circuits.

CD4047B Working in Circuit

The diagram shows the CD4047B operating in astable mode, where it generates continuous square wave signals without any external trigger. The astable inputs are enabled, allowing the internal multivibrator to switch automatically between HIGH and LOW states.

The oscillation frequency is set by the external RC network using R1 (560kΩ) and C1 (100nF). As the capacitor charges and discharges through the resistor, it controls the timing of the output signal.

The IC provides complementary outputs at Q (pin 10) and Q̅ (pin 11), along with an oscillator output (pin 13). These outputs produce stable and synchronized waveforms, with Q and Q̅ always inverted.

CD4047B CMOS Multivibrator Applications

• Clock generation

• Pulse generation

• Frequency division

• Timing control

• Delay generation

• LED flashing

• Signal modulation

• Waveform generation

• Switching control

• Oscillation generation

Comparison: CD4047B VS CD4047

Parameter	CD4047	CD4047B
Technology	CMOS	Buffered CMOS (Improved)
Supply Voltage Range	3V to 15V (typical)	3V to 18V
Input Voltage Range	Limited to supply range	Wider input tolerance
Output Drive Capability	Standard	Improved drive strength
Noise Immunity	Moderate	Higher noise immunity
Timing Accuracy	Good	More stable and precise
Power Consumption	Low	Lower / optimized CMOS power
Propagation Delay	Higher	Reduced delay
Frequency Stability	Standard	Improved stability
Operating Temperature Range	-40°C to +85°C (typical)	-55°C to +125°C
Package Options	Limited	Wider package availability
Reliability	Standard	Enhanced reliability

Mechanical Dimensions

Conclusion

The CD4047B offers improved performance compared to its predecessor, the CD4047. Its ability to operate in both astable and monostable modes, along with stable RC timing control and complementary outputs, makes it a valuable component for timing and waveform generation. The device also provides enhanced noise immunity, wider voltage range, and better overall stability, ensuring consistent operation across different conditions. CD4047B is available in multiple package options and equivalent models.

Frequently Asked Questions [FAQ]

1. What is the difference between CD4047B astable and monostable modes?

Astable mode generates continuous square waves, while monostable mode produces a single pulse when triggered.

2. How do you calculate the frequency of CD4047B?

The frequency is determined by external R and C values using formulas like t ≈ 4.40RC for astable outputs.

3. What voltage can CD4047B operate on?

It typically operates between 3V and 18V, depending on design requirements.

4. What is the function of the retrigger pin in CD4047B?

It allows the output pulse to extend if a new trigger arrives before the current pulse ends.

5. Why does CD4047B provide both Q and Q̅ outputs?

To deliver simultaneous normal and inverted signals without needing extra components.

6. Can CD4047B be used as a frequency divider?

Yes, it includes an internal divide-by-2 feature for stable frequency outputs.

7. What happens when the reset pin is activated?

The IC immediately stops operation and forces the output to a defined state.

8. How accurate is CD4047B timing?

Timing accuracy depends on external RC components and supply stability.

9. What factors affect CD4047B output stability?

RC component tolerance, temperature changes, and supply voltage variations can impact stability.