BCD-to-Decimal Decoder The CD4028 is a BCD-to-decimal decoder manufactured by various semiconductor companies, including Texas Instruments, ON Semiconductor, and NXP.
### **Key Specifications:**
- **Function:** Converts a 4-bit Binary-Coded Decimal (BCD) input to one of ten decimal outputs (0–9).
- **Inputs:** 4-bit BCD (A, B, C, D).
- **Outputs:** 10 active-high outputs (Q0–Q9).
- **Supply Voltage Range:** Typically **3V to 18V** (depending on manufacturer).
- **Operating Temperature Range:** **-55°C to +125°C** (military-grade versions may differ).
- **Propagation Delay:** Typically **60ns to 300ns** (varies with voltage and manufacturer).
- **Power Consumption:** Low static power dissipation (in the microwatt range for CMOS technology).
- **Package Options:** Available in **DIP (Dual In-line Package), SOIC, and TSSOP** formats.
### **Truth Table (BCD to Decimal Conversion):**
| D (MSB) | C | B | A (LSB) | Active Output (Q0–Q9) |
|---------|---|---|--------|-----------------------|
| 0 | 0 | 0 | 0 | Q0 |
| 0 | 0 | 0 | 1 | Q1 |
| 0 | 0 | 1 | 0 | Q2 |
| 0 | 0 | 1 | 1 | Q3 |
| 0 | 1 | 0 | 0 | Q4 |
| 0 | 1 | 0 | 1 | Q5 |
| 0 | 1 | 1 | 0 | Q6 |
| 0 | 1 | 1 | 1 | Q7 |
| 1 | 0 | 0 | 0 | Q8 |
| 1 | 0 | 0 | 1 | Q9 |
For invalid BCD inputs (1010 to 1111), all outputs remain inactive (low).
### **Manufacturer Variations:**
- **Texas Instruments (TI):** CD4028B (standard CMOS version).
- **ON Semiconductor:** MC14028B (similar specs).
- **NXP (formerly Philips):** HEF4028B (European equivalent).
For exact electrical characteristics, refer to the datasheet from the specific manufacturer.
