The **U74CBT3253G-R16-R** is a high-speed CMOS Dual 1-of-4 Field Effect Transistor (FET) Multiplexer/Demultiplexer. It is primarily used for signal switching in communication and computing systems. --- ### ## Technical Overview This integrated circuit (IC) acts as a high-speed bus switch. It features low "on" resistance, allowing for signal connections with minimal propagation delay and without adding significant noise or distortion. ### ### Key Specifications | Parameter | Specification | | :--- | :--- | | **Function** | Dual 1-of-4 Multiplexer/Demultiplexer | | **Technology** | CMOS / Bus Switch | | **Supply Voltage ($V_{CC}$)** | 4.0V to 5.5V | | **On-State Resistance ($R_{on}$)** | ~5Ω (Typical) | | **Propagation Delay** | < 0.25 ns | | **Operating Temperature** | -40°C to +85°C | | **Package Type** | SSOP-16 / TSSOP-16 (Depending on exact R16 suffix) | --- ### ## Pin Functionality The device is a "Dual" switch, meaning it contains two independent 4-channel blocks controlled by the same select lines. 1. **Select Inputs (S0, S1):** These pins determine which of the four input/output ports is connected to the common port. 2. **Output Enable ($\overline{OE}$):** When low, the switch is active. When high, the switch is in a high-impedance (Hi-Z) state (disconnected). 3. **1A, 2A:** Common ports for the two switch banks. 4. **1B1-1B4 / 2B1-2B4:** The four individual ports for each bank. --- ### ## Logic Truth Table | $\overline{OE}$ | S1 | S0 | Function | | :---: | :---: | :---: | :--- | | L | L | L | A Port connected to B1 Port | | L | L | H | A Port connected to B2 Port | | L | H | L | A Port connected to B3 Port | | L | H | H | A Port connected to B4 Port | | H | X | X | Disconnect (Hi-Z) | --- ### ## Typical Applications * **Memory Interleaving:** Switching between different banks of SDRAM or Flash memory. * **Video/Audio Switching:** Routing high-speed analog or digital signals between different sources. * **Bus Isolation:** Protecting sensitive components by disconnecting the bus during power-down or fault conditions. * **Level Shifting:** Can be used for 5V to 3.3V translation if configured correctly with a diode or specific voltage rails. --- ### ## Coding Example (Control Logic) If you were controlling this chip using an Arduino or microcontroller, the logic would look like this: ```cpp // Define Pins const int OE_PIN = 2; const int S0_PIN = 3; const int S1_PIN = 4; void selectChannel(int channel) { digitalWrite(OE_PIN, LOW); // Enable the chip // Binary logic for 1-of-4 selection digitalWrite(S0_PIN, (channel & 0x01)); digitalWrite(S1_PIN, (channel & 0x02) >> 1); } ```