Cross chip CC6421DN-RD

CC6421 is a one- chip solution for single- coil brushless DC motor/fan with PWM speed control. The device is designed in BCD technology, it integrates regulator, hall sensor, offset cancellation, AGC amplifier, a power output H- bridge and digital control. The voltage regulator operates from 3.5V to 18V The PWM input features a built- in pull- up resistor of 10Kohm. Since the interface providing the PWM signal is generally open- collector/drain type, an external resistor is not required. In addition, it provides a fail/safe functionality as it will drive the motor at full speed in case of signal wire- break. The Intelligent Soft Start prevents very high peak current during start- up. After power on, the duty cycle of output signal will increase from 25% to 50% by 5% every 100ms. During start up, CC6421 will detect magnet field strength and automatically adjust gain of amplifier. If CC6421 gets the right gain, or 1.5s after power on, it will change status from starting up to sine wave current mode. In sine wave current mode, CC6421 can change motor speed with PWM signal from 0.1Hz to 100KHz. The Minimal Speed input allows setting of a minimum required rotation speed of the motor by using 2 inexpensive resistors. This is especially useful for applications where minimum cooling is a requirement to avoid system damage. CC6421 can provide four rotational speed curves with different slopes by configuring different resistance between VREF and GND. In sine wave current mode, the output signal is a PWM signal modulated by 100KHz triangle signal. The coil will filter the high frequency and recovery sine wave current by its impedance. Sine wave current mode will dramatically increase motor efficiency and decrease noise. CC6421 provide FG and RD signal and its FGRD pin is protected against short- circuit. The device also features Locked Rotor Protection to avoid overheating issues in case of a mechanical blockage of the rotor or bearing failure. The on- chip Thermal Protection switches off the outputs if the junction temperature increases above an abnormally high threshold. It will automatically recover once the temperature decreases below a safe value. CC6421 is available in two packages, which are SOP8 and DFN8 3*3

• Built- in high sensitive hall sensor
• High efficiency
• Zero Current Switch (ZCS) and Zero magnet Switch (ZBS)
• Low noise
• PWM speed control with minimal speed setting
• High output current, up to 800mA
• Wide operating voltage, 3.5V to 18V
• Rotation Detect (RD) and Frequency Generator (FG) are optional
• Protection: Thermal Protection, LRP (Lock Rotation Protection), Current Limit Protection
• AGC control
• Intelligent Soft Start
• The rotational speed curve is configurable
• ESD (HBM) 6000V