8958

8958 LOGIC SUPPLY INHIBIT UV1 UV2 LIMIT GROUND AB GROUND AB PARK VOLTAGE SENSE IN– IN A+ IN A– OUT A 1 2 3 4 5 6 7 8 9 9 B 10 11 12 1.5 V + V CC VOICE COIL MOTOR DRIVER 24 23 22 21 20 19 18 17 SENSE OUT PARK DRIVE PARK GROUND PWR OK GROUNDAB GROUNDAB SENSE IN+ IN B+ IN B– LOAD SUPPLY OUT B Providing control and drive of the voice coil motor used for head positioning in disk drive applications, the A8958CLB is a full-bridge driver which can be configured so that its output current is a direct function of an externally applied control voltage or current. This linear current control function is supplemented by additional circuitry to protect the heads and the data disk during system failure or normal system shutdown. The two ±800 mA driver outputs provide very-low saturation voltage drops and precise current control utilizing a single current-sensing resistor connected in series with the load. Under-voltage lockout disables the system in a controlled sequence if a fault condition occurs. When activated by the under-voltage comparator, or a park command, the output power drivers change from a controlled current to a user-determined constant park voltage. Other features include a power ok flag, a limit input to force the outputs to their maximum level in either polarity, an over-riding output disable to shut down both power amplifiers and reduce quiescent supply current, and internal thermal shutdown which disables the load (but still allowing the head to be parked) in the event...