
Motor driver ICs
Fan motor driver IC
BA6811F / BA6813F
The BA6811F and BA6813F are 2-phase, half-wave motor drivers suited for 12V fan motors. Built-in lock detection and
automatic restart mechanisms protect motors. Compact SOP8 (BA6811F/BA6813F) packages reduce the number of
external components required.
Applications
2-phase fan motors
Features
1) Built-in power transistors.
2) Lock detection and automatic restart mechanisms.
3) Built-in thermal shutdown circuit.
Absolute maximum ratings (Ta = 25C)
4) Alarm output pin. (BA6811F)
5) Hall signal output pin. (BA6813F)
6) Built-in reverse current protection diode.
Recommended operating conditions (Ta = 25C)
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Motor driver ICs BA6811F / BA6813F
Block diagram
Pin descriptions
Hall input / output truth table
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Motor driver ICs BA6811F / BA6813F
Input / output equivalent circuits
Electrical characteristics (unless otherwise noted, Ta = 25C, V
CC = 12V)
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Motor driver ICs BA6811F / BA6813F
FCircuit operation
The BA6811F and BA6813F 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 :
C S (V
TON (Charge time)=
TOFF (Discharge time)=
LDCLVLDCP)
I
LDC
LDCLVLDCP)
C S (V
ILDD
where
V
LDCL is the LD-pin clamp voltage (1.93V),
LDCP is the LD-pin comparator voltage (0.76V),
V
LDC is the LD-pin charge current (2.9µA),
I
LDD is the LD-pin discharge current (0.52µA),
I
C is the capacitance of the LD-pin external capacitor.
For C=1µF , for example, the charge (output ON) and discharge (output OFF) times are 0.40s and 2.25s, respectively.
The timing chart for an occasion of motor locking is
shown in Fig. 1.
(Typical value)
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Motor driver ICs BA6811F / BA6813F
Application example
Operation notes
(1) Thermal shutdown circuit
The IC has a built-in thermal shutdown circuit. The is a
temperature difference of 25C (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.
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(2) Power consumption
Power consumed in the IC can be calculated from the following equation :
P
C=PC1)PC2)PC3
C1 is power consumed by the circuit current.
P
C1=VCC ICC
P
PC2 is the output current consumption.
P
C2=VOL IO
VOL is the LOW level output voltage of output pins
1 and 2, and I
C3 is power consumed by the AL and HO pins.
P
C3=VALL IAL)VHOL IHO /2
P
O is the sink current of pins 1 and 2.
where
V
ALL is the AL-pin LOW level voltage,
AL is the AL-pin sink current,
I
HOL is the HO-pin LOW level voltage,
V
HO is the HO-pin sink current.
I
Make sure that your application does not exceed the allowable power dissipation of the IC.

Motor driver ICs BA6811F / BA6813F
(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
CC*2.8V) including the signal amplitude.
to (V
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 :
where RH is the Hall device impedance.
VCC
R1)R2)RH
External dimensions (Units: mm)
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