Texas Instruments CD4047BF

Overview

CD4047BF from Texas Instruments is a CMOS retriggerable monostable multivibrator and astable multivibrator IC in a 14-lead hermetic ceramic dual-in-line package (CDIP), operating from 3 V to 18 V, with propagation delay of 120 ns at 10 V, output drive capability of ±4.2 mA, and guaranteed operation over -55°C to +125°C for aerospace and high-reliability timing applications.

For engineers reviewing the CD4047BF datasheet, CD4047BF pinout, CD4047BF application, or CD4047BF equivalent, this device serves as a precision low-power timing generator in systems requiring stable oscillation, pulse shaping, or gated clock synthesis without external RC network drift compensation.

Technical Context

The CD4047BF integrates complementary MOSFET transistors to implement both astable and monostable modes via mode-select input (MODE), supporting edge-triggered retriggering in monostable operation and frequency-adjustable square-wave generation in astable mode using two external resistors and one capacitor. Its internal Schmitt-trigger inputs ensure noise immunity on trigger and reset lines.

It features independent reset (RESET) and trigger (TRIG) inputs with hysteresis, buffered complementary Q and Q̅ outputs capable of driving TTL and CMOS loads, and a built-in oscillator section that eliminates need for external timing components in basic astable configurations when using internal feedback paths.

Key Specifications

Pinout & Package

CD4047BF is housed in a 14-lead hermetic ceramic dual-in-line package (CDIP, J suffix), 5.08 mm maximum height, with SNPB lead finish and no RoHS compliance. The package provides hermetic sealing for long-term reliability in harsh environments including vacuum, humidity, and radiation exposure.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4047BE and CD4047BM96, the CD4047BF offers superior long-term parameter stability and hermetic reliability in mission-critical timing roles, while sacrificing RoHS compliance and surface-mount compatibility - making it the sole choice for MIL-STD-883 qualified programs.

Availability

CD4047BF is available at Aetrix Electronics and suitable for aerospace power sequencing, industrial control logic, and test instrumentation requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD4047BF 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 high-reliability logic solutions with over 50 years of aerospace and defense component heritage.

The CD4047B series was designed specifically for high-stability, low-power timing functions in military, space, and industrial systems where environmental resilience and long-term parametric consistency are mandatory.

FAQ

What is the maximum operating frequency of CD4047BF in astable mode?

The CD4047BF supports astable operation up to 1 MHz with appropriate external R-C values. At 10 V supply, propagation delay remains ≤120 ns, enabling reliable square-wave generation with 50% duty cycle stability across the full frequency range. Frequency accuracy depends on external component tolerances and temperature coefficients.

Does CD4047BF require external components to operate in monostable mode?

Yes, CD4047BF requires one external capacitor (Cext, Pin 4) and one resistor (Rext, Pins 5–6) to set monostable pulse width as 2.2 × R × C. No additional components are needed for basic functionality, and the internal Schmitt-trigger input eliminates need for external debouncing circuitry on the TRIG line.

Can CD4047BF drive TTL logic directly?

Yes, CD4047BF can directly drive standard TTL inputs: its ±4.2 mA output drive at 10 V exceeds the TTL input current requirements (IIH = 40 µA, IIL = 1.6 mA). For reliable interfacing, ensure VDD ≥ 4.5 V when driving multiple TTL loads to maintain valid logic thresholds.

Is CD4047BF pin-compatible with CD4047BE?

Yes, CD4047BF and CD4047BE share identical pinout, electrical specifications, and functional behavior. The only differences are package type (hermetic ceramic CDIP vs. plastic PDIP), lead finish (SNPB vs. NIPDAU), and RoHS status - making them functionally interchangeable in existing designs where environmental rating permits.

What is the purpose of Pin 10 (ASTABLE OUT) on CD4047BF?

Pin 10 is the internal astable oscillator node, intended solely for feedback within the chip's internal timing loop. It is not buffered and exhibits high impedance and sensitivity to capacitive loading; connecting external circuitry to Pin 10 will disrupt oscillation stability and is strictly prohibited in production designs.