## Overview of the 74ACT05 IC The **74ACT05** is a high-speed CMOS device featuring **six independent hex inverters** with **open-drain outputs**. It belongs to the "ACT" logic family, which means it is Advanced CMOS technology with TTL-compatible inputs. --- ### Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Logic Function** | Hex Inverter (NOT Gate) | | **Output Type** | Open-Drain | | **Supply Voltage ($V_{CC}$)** | 4.5V to 5.5V | | **Input Logic Levels** | TTL Compatible ($V_{IL} \le 0.8V, V_{IH} \ge 2.0V$) | | **Output Sink Current ($I_{OL}$)** | 24 mA | | **Propagation Delay** | ~5.0 ns (typical) | | **Operating Temperature** | -40°C to +85°C | --- ### Internal Structure and Pinout The 74ACT05 contains six individual circuits. Because it is **open-drain**, the output transistor can only pull the signal to Ground (LOW). To achieve a HIGH state, an external pull-up resistor must be connected to the output. #### Pin Configuration (14-Pin DIP/SOIC) 1. **1A** - Input 1 2. **1Y** - Output 1 3. **2A** - Input 2 4. **2Y** - Output 2 5. **3A** - Input 3 6. **3Y** - Output 3 7. **GND** - Ground 8. **4Y** - Output 4 9. **4A** - Input 4 10. **5Y** - Output 5 11. **5A** - Input 5 12. **6Y** - Output 6 13. **6A** - Input 6 14. **$V_{CC}$** - Power Supply --- ### Distinctive Features * **Open-Drain Outputs:** This allows for "wired-AND" logic. Multiple outputs can be connected to a single pull-up resistor. If any inverter output goes LOW, the entire line goes LOW. * **Voltage Level Shifting:** Since the output is open-drain, you can pull the output to a different voltage level (e.g., pulling a 5V logic signal up to 12V), provided it stays within the breakdown limits of the chip. * **High Speed:** Being part of the ACT family, it offers speeds comparable to the 74F (Fast) bipolar series while consuming significantly less power. ### Truth Table | Input (A) | Output (Y) | Resulting State | | :--- | :--- | :--- | | Low (L) | Z (High Impedance) | Floating (Requires Pull-up to be High) | | High (H) | Low (L) | Sinks current to Ground | --- ### Common Applications * **Level Shifters:** Converting between different logic voltage domains. * **LED Drivers:** Sinking current to turn on LEDs. * **Bus Buffers:** Driving signals on a shared communication line. * **Logic Inversion:** Standard NOT gate functionality in high-speed systems.