Datasheet BA6406F Datasheet (ROHM)

Motor driver ICs

2-phase half-wave motor predriver

BA6406F

The BA6406F is a 2-phase, half-wave motor predriver suited for fan motors.
Features

1) Lock detection and rotational speed sensing mecha­nisms are built in.

2) Compact 8-pin SOP package reduces the number of
external components required.

Absolute maximum ratings

3) Automatic restart when the motor lock is undone.

4) Hall inputs have a hysteresis.

Operating power supply voltage (Ta = 25C)

695

Motor driver ICs BA6406F

Block diagram and application example

Electrical characteristics (unless otherwise noted, Ta = 25C and V

696

CC = 12V)

Motor driver ICs BA6406F

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 BA6406F , automatic restart is performed in the fol­lowing manner. A motor lock condition is detected when

the Hall signal stops switching. The output is ON when
pin 6 is being charged, and OFF when pin 6 is being dis­charged. Pin 3 is ON during normal operation, and OFF
when the motor is locked. Pin 3 is an open collector out­put.

Output ON time (t
the pin6 capacitor
where

tON =

tOFF =

C S (V

C S (V

ON) and OFF time (tOFF) determined by

6CLV6CP)

I6C

6CLV6CP)

6d

I

(sec)

(sec)

C is the capacitance of the pin-6 external capacitor

6CL is the pin6 clamp voltage

V
V

6CP is the pin6 comparator voltage

6C is the pin6 charge current

I

6d is the pin6 discharge current

I

697

Motor driver ICs BA6406F

Operation notes
(1) The lock detection output pin (pin 3) may maintain
HIGH level for a few hundred milliseconds when the pow­er is turned on.

(2) Allowable power dissipation
The allowable power dissipation is plotted against ambi­ent temperature in Fig. 3.
(3) Power dissipation
Power consumed in the I

C can be calculated from the fol-

lowing equation:

C = PC1+PC2+PC3

P

(1) PC1 is power consumed by the circuit current.

C1 = VCC ICC

P

(2) PC2 is the output current consumption.

C2 = (VCC*VOH) IO

P

Electrical characteristic curves

VOH is the HIGH level voltage of pins 7 and 8. Power dis­sipation can be reduced by raising the hfe-rank of the ex­ternal output transistor and thereby reducing the I

C3 is power consumed by pin 3.

(3) P

P

C3 = V3L I3

O value.

where V3L is the pin-3 LOW level voltage and I3 is the
pin-3 current. Make sure that your application does not
exceed the allowable power dissipation of the IC.

698

Motor driver ICs BA6406F

External dimensions (Units: mm)

699