The **SMA3VG-CB2-R** is a specific model of a **Surface Mount (SMT) Vibration Motor**, commonly known as a "Pancake" or "Coin" motor. These are widely used in portable electronics to provide haptic feedback or silent alerts. --- ## 1. Technical Specifications Below are the typical electrical and mechanical characteristics for this class of component: | Parameter | Specification | | :--- | :--- | | **Motor Type** | Brushed DC (ERM - Eccentric Rotating Mass) | | **Rated Voltage** | 3.0V DC | | **Operating Voltage Range** | 2.5V – 3.5V DC | | **Rated Current** | Max 80mA - 100mA | | **Rated Speed** | ~12,000 RPM | | **Mounting Type** | Surface Mount (SMT / SMD) | | **Operating Temperature** | -20°C to +70°C | --- ## 2. Key Features * **Reflow Solderable:** Unlike leaded vibration motors that require manual soldering, the "CB2" series is designed for automated pick-and-place assembly and infrared reflow soldering. * **Compact Form Factor:** The "Coin" design allows it to fit into extremely thin devices like smartwatches or slim smartphones. * **ERM Technology:** It uses an internal offset weight (eccentric mass). When the motor spins, the imbalance creates the centrifugal force perceived as vibration. * **Polarity Sensitive:** While it will spin in both directions, it is usually optimized for a specific polarity marked on the PCB pads. --- ## 3. Circuit Implementation When integrating the SMA3VG-CB2-R into an electronic design, specific protective components are required because motors are inductive loads. ### Typical Drive Circuit ```text [MCU GPIO] ---> [1k resistor] ---> [Base of NPN Transistor/Gate of MOSFET] | [VCC 3V] --+-- [Motor +] | | [Diode] [Motor -] -- [Collector/Drain] | | GND GND ``` ### Critical Design Components: 1. **Flyback Diode:** A Schottky diode should be placed in parallel with the motor to protect the switching transistor from voltage spikes (back-EMF) when the motor stops. 2. **Decoupling Capacitor:** A 0.1µF to 10µF capacitor is often placed near the motor to suppress electrical noise generated by the internal brushes. 3. **Switching Element:** Since a microcontroller cannot provide 80mA-100mA directly from a GPIO pin, a MOSFET or BJT is required to switch the motor power. --- ## 4. Common Applications * **Wearables:** Fitness trackers and smartwatches for notifications. * **Handheld Medical Devices:** For tactile alerts in noisy environments. * **IoT Devices:** User feedback for button presses (Haptics). * **Mobile Communication:** Pagers or slim mobile handsets.