BA6845FS

Motor driver ICs Stepping motor driver BA6845FS The BA6845FS is a stepping motor driver with a maximum output current of 1.0A. The logic input allows three output modes : forward, reverse, and power save. The IC has a low output saturation voltage and is capable of driving motors at low supply voltage. FApplications Stepping motors for floppy disk drives FFeatures 1) Low output saturation voltage. 2) Power save circuit. 3) Thermal shutdown circuit. FAbsolute maximum ratings (Ta = 25_C) FRecommended operating conditions (Ta = 25_C) 735 Motor driver ICs FBlock diagram BA6845FS 736 Motor driver ICs FPin descriptions BA6845FS FInput / output circuits (all resistances are typical values) 737 Motor driver ICs FElectrical characteristics (unless otherwise noted, Ta = 25_C, VCC = 5V) BA6845FS FTruth table 738 Motor driver ICs FApplication example BA6845FS FOperation notes (1) Control logic pins Do not apply voltage to control logic pins (pins 4, 5, 12, and 13) when the VCC voltage is not applied to the IC. The voltage of each pin should be less than VCC, if applied, and should be more than the ground voltage. (2) PCB arrangement When changing the rotational direction of a motor, a large current of up to a few hundred milliamperes can flow between the motor power supply (pins 11 and 14) and MGND (pins 1 and 8). Depending on the application, this large output current may flow back to input pins, resulting in output oscillation or other malfunctions. Make sure that your design does not allow a common impedance between the large current output lines and the input section. Suppress the power supply impedance to low levels, otherwise output oscillation may occur. (3) Package power dissipation The power dissipated by the IC varies widely with the supply voltage and the output current. Give full consideration to the package power dissipation rating when setting the supply voltage and the output current. (4) Ground pins Pins 1, 3, 6, and 8 should have the lowest potential (ground potential) in the IC. (5) Thermal shutdown circuit This circuit shuts down all the driver outputs when the chip junction temperature is increased to about 175_C (typical). The thermal shutdown circuit is deactivated when the temperature drops to about 20_C (typical). (6) Input pins (pins 4, 5, 12, and 13) These pins have characteristics negatively correlated to temperature. Give full consideration to the temperature effect when using the IC. 739 Motor driver ICs FElectrical characteristic curves BA6845FS FExternal dimensions (Units: mm) 740