Motor driver ICs 2-phase half-wave motor driver BA6407AF The BA6407AF is a motor driver dedicated to 12V fan motors. Built-in output transistors reduce the number of external components required. The IC has a lock signal output pin. Applications Fan motors Features 1) Lock detection and rotational speed sensing mechanisms are built in. 2) Compact SOP 8-pin package reduces the number of external components required. Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 700 3) Automatic restart when the motor lock is undone. Motor driver ICs BA6407AF Block diagram Pin descriptions 701 Motor driver ICs BA6407AF FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 12V) FLock detection The automatic restart circuit detects a motor lock condition and automatically turns off the output current. When the lock condition is cleared, the IC automatically restarts and allow the motor to run. In the BA6407AF, automatic restart is performed as follows. A motor lock condition is detected when the Hall signal stops switching. The output is ON when the LD pin is being charged, and OFF when the pin is being discharged. S The AL pin is ON during normal operation, and OFF when the motor is locked. S The AL pin is an open collector output. 702 Output ON time (TON) and OFF time (TOFF) determined by the LD capacitor C S (VLDCLVLDCP) TON (Charge time)= ILDC TOFF (Discharge time)= C S (VLDCLVLDCP) ILDD (Typical value) where C is the capacitance of the LD-pin external capacitor, VLDCL is the LD-pin clamp voltage (2.48V), VLDCP is the LD-pin comparator voltage (0.99V), ILDC is the LD-pin charge current (3.4µA), ILDC is the LD-pin discharge current (0.79µA). Motor driver ICs BA6407AF Application example 703 Motor driver ICs BA6407AF Operation notes (1) Thermal shutdown circuit The IC has a built-in thermal shutdown circuit. There is a temperature difference of 25C (typical) between the temperatures at which the circuit is activated and deactivated. The Hall current is given by: VCC R1)R2)RH where RH is the hall device impedance. Fig.3 (2) Power dissipation Power consumed in the IC can be calculated from the following equation : PC=PC1)PC2)PC3 PC1 is power consumed by the supply current. PC1=VCC ICC PC2 is the output current consumption. PC2=VOL IO VOL is the LOW level voltage of output pins 1 and 2. PC3 is power consumed by the AL pin. PC3=VALL IAL where VALL is the AL-pin LOW level voltage and IAL is the AL-pin sink current. Make sure that your application does not exceed the allowable power dissipation of the IC. (3) 704 Hall amplifier input voltage The R1 and R2 resistances must be set so as to maintain the Hall amplifier input bias voltage within the range of 1V to (VCC*2V) including the signal amplitude. It is recommended that the same value be used for both resistors so that the Hall device output signal is centered around VCC / 2. The Hall device may be affected by power supply noise due to the PCB conductor pattern. If you have this problem, insert a capacitor C1 as shown in Fig. 5. If the conductor lines from the Hall device output terminals to the Hall inputs of the IC are particularly long, noise can be picked up and fed into the inputs. If you have this problem, insert a capacitor C2 as shown in Fig. 5. Note that the Hall inputs have no hysteresis in this IC. Motor driver ICs BA6407AF Electrical characteristic curves External dimensions (Units: mm) 705