Fan driver simplifies circuit design

Aimed at low to medium voltage brushless DC fan control in consumer, home appliance, industrial and office equipment, the AH5772 and AH5773 are said to enable a reduction in component count and PCB area where space is at a premium. By integrating both high sensitivity Hall sensors and companion input amplifiers, the devices can be used with lower strength fan motor magnets, achieving additional cost savings. The sensors' tolerances are also very small, helping to reduce variability in motor performance and simplifying manufacturing and testing. A built-in low RDS_(on) H-bridge output stage enables the fan drivers to support source and sink currents of up to 500mA continuous, 1A peaks. The devices' low profile, low pin count package options are MSOP8-EP and U-DFN2020-6 (planned Q4 2014) for the AH5773 and TO-94 for the AH5772. The fan drivers' operating voltage range, from 2.4 to 18V, suits a variety of brushless DC cooling fan applications, with the low start up voltage permitting fan operation down to 20% of nominal 12V supply. Operating temperature range is between -40 and 105ºC. rs include over-voltage protection, which shuts the devices down upon detecting an over-voltage situation; putting the AH5772 and AH5773 in standby mode to prevent motor coil stress. An over-temperature shutdown function provides the devices with thermal protection.