Motor driver ICs 2-phase half-wave motor driver BA6809F / BA6819AF The BA6809F and BA6819AF are motor drivers designed for 3V and 5V fan motors. Built-in output transistors reduce the number of external components required. The ICs have an alarm output pin (BA6809F) and Hall output pin (BA6819AF). Applications Fan motors Features 1) Lock detection and rotational speed sensing mechanisms are built in. 2) Alarm output pin (BA6809F) and Hall output pin (BA6819AF). Absolute maximum ratings (Ta = 25C) Recommended operating conditions (Ta = 25C) 706 3) Built-in thermal shutdown circuit. 4) Operation assured with a supply voltage as low as 2.7V. 5) Compact 8-pin SOP package. Motor driver ICs BA6809F / BA6819AF Block diagram Pin descriptions Hall input / output truth table 707 Motor driver ICs Input / output circuits Electrical characteristics (unless otherwise noted, Ta = 25C and VCC = 3V) 708 BA6809F / BA6819AF Motor driver ICs BA6809F / BA6819AF FCircuit operation The BA6809F and BA6819AF have motor lock detection and automatic restart circuits. The timing of lock detection and automatic restart is determined by the external capacitor connected to the LD pin. The charge time of the external capacitor is given by : ton (Charge time)= toff (Discharge time)= C S (VLDCLVLDCP) ILDC C S (VLDCLVLDCP) ILDD (Typical value) where VLDCL is the LD-pin clamp voltage (1.90V), VLDCP is the LD-pin comparator voltage (0.73V), (2.2µA), ILDC is the LD-pin charge current (0.42µA), ILDD is the LD-pin discharge current C is the capacitance of the LD-pin external capacitor. For C=0.47µF, for example, the charge and discharge times are 0.25s (output ON) and 1.31s (output OFF), respectively. FApplication example 709 Motor driver ICs Operation notes (1) Thermal shutdown circuit The IC has a built-in thermal shutdown circuit. The is a temperature difference of 20C (typical) between the temperatures at which the circuit is activated and deactivated. The circuit is activated at the temperature of about 175C (typical), so that all outputs are turned OFF. Normal operation resumes when the circuit is deactivated. (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 circuit current. PC1=VCC ICC PC2 is the output current consumption. PC2=VOL IO VOL is the LOW level output voltage of output pins 1 and 2, and IO is the sink current of pins 1 and 2. PC3 is power consumed by the AL and HO pins. PC3=VALL IAL (BA6809F) PC3=VHOL IHO / 2 (BA6819AF) where VALL is the AL-pin LOW level voltage, IAL is the AL-pin sink current, VHOL is the HO-pin LOW level voltage, IHO is the HO-pin sink current. Make sure that your application does not exceed the allowable power dissipation of the IC. 710 BA6809F / BA6819AF (3) 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 0V to (VCC*2V) including the signal amplitude. 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. Hall current is given by= VCC R1)R2)RH where RH is the Hall device impedance. Motor driver ICs BA6809F / BA6819AF External dimensions (Units: mm) 711