The **UT3222G-R20-R** is a specific integrated circuit produced by Unisonic Technologies (UTC). It is a low-voltage, high-speed interface IC designed to bridge the gap between TTL/CMOS logic levels and RS-232 standards. ### Technical Specifications Below is a breakdown of the key electronic characteristics of the UT3222 series: | Parameter | Value / Description | | :--- | :--- | | **Device Type** | RS-232 Transceiver (3.0V to 5.5V) | | **Driver/Receiver Configuration** | 2 Drivers / 2 Receivers | | **Data Rate** | Typically up to 250 kbps | | **Operating Voltage** | 3.0V ~ 5.5V | | **Supply Current** | 0.3mA (Typical) | | **Shutdown Current** | 1µA (Power-saving mode) | | **Package Type** | SSOP-20 (indicated by the "R" suffix) | --- ### Core Components and Functionality #### 1. Dual Charge Pump The IC contains an internal charge pump that allows it to operate from a single low-voltage power supply (3.3V or 5V). It uses four external capacitors to generate the positive and negative voltages (+5.5V and -5.5V) required for RS-232 communication levels. #### 2. Transmitters (Drivers) The two transmitters convert TTL/CMOS input levels into the bipolar signals required for RS-232. They feature: * **Slew Rate Control:** Limited to reduce electromagnetic interference (EMI). * **Short Circuit Protection:** Protects the pins from damage if grounded. #### 3. Receivers The two receivers convert RS-232 input signals back into 5V or 3V logic levels. These receivers are active even in shutdown mode, allowing the system to "wake up" upon detecting signal activity. #### 4. Power Management Features The "3222" variant is specifically known for its power-saving modes: * **Shutdown Mode:** Disables the charge pump and transmitters to reduce current consumption to 1µA. * **Enable Pin (EN):** Allows the receiver outputs to be placed in a high-impedance state, permitting multiple devices to share a single UART bus. --- ### Part Number Breakdown * **UT3222**: The base model (RS-232 Transceiver with shutdown feature). * **G**: Halogen-free and RoHS compliant. * **R20**: Refers to the **SSOP-20** package size. * **R**: Tape and Reel packaging. ### Typical Applications * Battery-powered portable equipment (Handheld terminals). * Notebook and Laptop computers. * High-speed modems. * Industrial control interfaces.