7447 IC BCD to 7-Segment Decoder
The IC 7447 functions as a BCD to 7-segment decoder/driver. It accepts a 4-bit binary-coded decimal input (BCD) and generates seven active-low outputs labeled a–g, which control a common-anode 7-segment display. Each output drives one segment to display decimal digits from 0 to 9. Inputs from 1010 to 1111 produce blank or undefined patterns.
The IC also includes ripple-blanking inputs and outputs, letting you cascade multiple ICs for multi-digit displays. It simplifies display control by removing the need for complex logic or microcontroller code. Engineers use the 7447 to interface digital counters, microcontrollers, or keypads with standard numeric LED displays.
Its TTL-compatible logic ensures seamless integration with 7400-series systems. The IC can sink sufficient current to directly drive many LED segments, though series resistors are typically required.
Key Features
Converts 4-bit BCD input into 7 control signals
Drives common-anode 7-segment LED displays
Outputs are active-low for direct segment control
Supports ripple blanking and display blanking control
TTL-compatible input and output levels
Compact DIP-16 or SOIC-16 package
Reduces logic complexity in display circuits
Applications
Display decimal digits on 7-segment LED modules.
Drive numeric readouts in digital counters or clocks.
Interface keypads and binary inputs with visual output.
Control multiple displays using ripple-blanking features.
Build user interfaces in test equipment or meters.
Display step counts in timers, counters, and up/down counters.
Create number indicators in vending machines or kiosks.
Show status codes in automation systems.
Add numeric feedback to embedded or microcontroller projects.
Demonstrate BCD logic conversion in educational labs.
Specifications Table
| Parameter | Value |
|---|---|
| Logic Family | TTL |
| Input Type | 4-bit BCD |
| Output Type | 7 active-LOW lines (a–g) |
| Display Type | Common-Anode 7-Segment |
| Output Current (Sink) | Up to 24 mA per segment |
| Input HIGH Voltage | ≥ 2.0V |
| Input LOW Voltage | ≤ 0.8V |
| Output LOW Voltage | ≤ 0.4V |
| Output HIGH Voltage | ≥ 2.4V |
| Supply Voltage (Vcc) | 4.75V to 5.25V |
| Operating Voltage | 5V ‘ |
| Propagation Delay | ~20–30 ns |
| Power Consumption | ~25 mW |
| Operating Temperature | 0°C to 70°C |
| Package Type | DIP-16 / SOIC-16 |
| Pin Count | 16 |
