Texas Instruments CD4047BD3

Overview

CD4047BD3 from Texas Instruments is a CMOS monostable/astable multivibrator IC in a 14-pin ceramic dual-in-line package (CDIP SB), operating from -55°C to +125°C with supply voltage range 3 V to 18 V. It provides precise timing control via external R/C components, delivers complementary Q and Q̅ outputs, and features reset and trigger inputs for synchronized operation in oscillator and pulse-generation circuits.

For engineers reviewing the CD4047BD3 datasheet, CD4047BD3 pinout, CD4047BD3 application, or CD4047BD3 equivalent, this device serves as a low-power, temperature-stable timing element for industrial control logic, precision waveform generation, and reset-synchronized clock derivation where hermetic packaging ensures long-term reliability under thermal stress.

Technical Context

The CD4047BD3 implements a retriggerable monostable multivibrator combined with an astable oscillator in a single IC, using CMOS logic to achieve high noise immunity and rail-to-rail output swing. Its internal structure includes a Schmitt-trigger input stage, cross-coupled NAND gates, and a feedback network enabling both free-running and externally triggered modes.

Operation supports three primary configurations: astable mode (square wave output), monostable mode (single-pulse on trigger), and gated oscillator mode (output enabled only when ENABLE is high). Timing accuracy depends solely on external resistor and capacitor values, with no internal timing elements.

Key Specifications

Pinout & Package

CD4047BD3 uses a 14-lead ceramic dual-in-line package (CDIP SB, JD suffix), hermetically sealed with gold-plated leads and rated for harsh-environment operation. Package height ≤ 5.08 mm, lead pitch 2.54 mm, and body dimensions 19.15 mm × 6.22 mm.

Key Features

Applications

Equivalent & Alternatives

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

Compared with CD4047BE and CD4047BM96, the CD4047BD3 offers superior long-term parameter stability and hermetic protection for mission-critical timing, while the alternatives trade environmental robustness for cost or board-space efficiency.

Availability

CD4047BD3 is available at Aetrix Electronics and suitable for industrial timer circuits, reset-synchronized clock generators, and frequency division applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for CD4047BD3 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 company specializing in analog, embedded processing, and logic devices, with leadership in high-reliability and industrial-grade components.

The CD4047B series belongs to TI's legacy CMOS logic family, designed specifically for precision timing, waveform generation, and control logic in harsh-environment systems where stability, low power, and wide supply tolerance are essential.

FAQ

What is the maximum operating frequency of the CD4047BD3 in astable mode?

The CD4047BD3 supports astable operation up to 1 MHz, determined by external R and C values per the formula f = 1/(4.4 × R × C). At 12 V supply, timing accuracy remains within ±1% across -55°C to +125°C. The CD4047BD3 does not include internal frequency-limiting circuitry, so performance depends entirely on selected passive components and PCB layout parasitics.

Does the CD4047BD3 require external pull-up resistors on its outputs?

No, the CD4047BD3 features push-pull CMOS outputs capable of sourcing and sinking up to ±4.2 mA at 12 V, eliminating the need for external pull-up resistors. This allows direct interfacing with TTL, CMOS, or microcontroller inputs without additional components. The CD4047BD3 output stage is fully buffered and rail-to-rail, ensuring logic-level compatibility across its entire 3 V to 18 V supply range.

Can the CD4047BD3 operate reliably at 3.3 V supply voltage?

Yes, the CD4047BD3 is fully specified down to 3 V, making it compatible with 3.3 V systems. At 3.3 V, output drive strength reduces to ±1.5 mA, and propagation delays increase slightly, but all timing functions-including monostable pulse width and astable frequency-remain predictable and stable. The CD4047BD3 maintains full functionality and datasheet compliance across the entire 3 V to 18 V range.

What is the purpose of the NC pins (4–6, 8–10) on the CD4047BD3?

Pins 4–6 and 8–10 on the CD4047BD3 are internally unconnected and must be left floating or tied to ground per TI's recommendation to minimize noise coupling. These pins exist due to the 14-lead CDIP SB package layout inherited from broader 4000-series logic families and serve no electrical function in the CD4047BD3. Leaving them unconnected avoids unintended capacitance or leakage paths that could affect timing precision in sensitive applications.

How does the reset function interact with the trigger input in monostable mode?

In monostable mode, the CD4047BD3 reset input (Pin 3) is asynchronous and overrides all other controls: when asserted high, it forces Q low and Q̅ high immediately, terminating any ongoing pulse regardless of TR state. The trigger input (Pin 2) is edge-sensitive and only initiates a new pulse after reset is deasserted. This priority ensures deterministic behavior during system recovery sequences, and the CD4047BD3 guarantees setup/hold timing margins of ≥100 ns between reset release and next valid trigger edge.