## Overview of the LB1663M The **LB1663M** is a specialized monolithic integrated circuit (IC) developed by Sanyo (now part of ON Semiconductor). It is primarily designed as a **2-phase unipolar drive motor driver**, specifically optimized for driving brushless DC (BLDC) fans, such as those used in computers and office equipment. --- ### 1. Key Internal Components The IC integrates several critical electronic sections into a single small-outline package (MFP10S): | Component Section | Function | | :--- | :--- | | **Hall Amplifier** | Processes signals from an external Hall element to detect rotor position. | | **Hysteresis Comparator** | Prevents "chattering" or false triggering caused by noise in the Hall signal. | | **Output Drivers** | High-current transistors (Darlington pairs) that drive the motor coils directly. | | **Protection Circuitry** | Includes Thermal Shutdown (TSD) and Lockup Protection. | --- ### 2. Technical Specifications The electrical characteristics define its operational limits: | Parameter | Value (Typical) | | :--- | :--- | | **Supply Voltage (Vcc)** | 4.0V to 18V | | **Output Current (Iout)** | Up to 1.5A (Peak) | | **Saturation Voltage** | 1.1V @ 0.5A | | **Package Type** | MFP-10S (Surface Mount) | --- ### 3. Functional Features #### A. Lockup Protection and Automatic Recovery If the fan motor becomes physically obstructed (locked), the IC detects the lack of phase transitions. To prevent the coils from overheating or burning out, the IC cuts the output current. It then periodically attempts to restart the motor automatically once the obstruction is removed. #### B. Rotation Detection (RD) Output The LB1663M features an **RD pin** (typically Pin 1). - **Normal Operation:** The pin remains at a "Low" voltage level. - **Locked State:** The pin goes "High" (Open Collector), signaling the system controller that the fan has failed. #### C. Built-in Zener Diode It includes a Zener diode at the output stage to absorb "kickback" or inductive spikes generated when the motor coils are switched. This protects the internal transistors from overvoltage damage. --- ### 4. Typical Application Circuit In a standard configuration, the LB1663M requires very few external components: 1. **Hall Element:** Connected to pins 4 and 5 to sense magnetic poles. 2. **Motor Coils:** Connected between Vcc and pins 8/10 (OUT1/OUT2). 3. **Timing Capacitor:** Connected to pin 3 to determine the lockup detection and restart timing.