BA6402F datasheet(2/3 Pages) ROHM

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690

Motor driver ICs

BA6402F

FElectrical characteristics (unless otherwise noted, Ta = 25_C and VCC = 12V)

FRotational speed sensing and lock detection (6 pin)

The circuit around pin 6 is described in Fig. 1. Normally,

the C6 external capacitor is charging or discharging

around the Hall signal when the motor is running. When

the motor is locked, discharging does not occur at C6 be-

cause the Hall signal stops switching. Charging contin-

ues at C6 until the voltage increases to the pin-6 clamp

voltage, and then Q1 turns ON to turn OFF the output.

With the pin-6 current being constant (I6=6.8

µA, typical),

the time required after the motor is locked until the output

current is turned OFF (duration between B and C in Fig.

2) is determined by the C6 capacitance.

where V6CL is pin-6 clamp voltage (nearly equal to 5VBE)

For C6=2.2

µF, for example, Toff is about 0.91s (typical).

FOperation notes

(1)

Hall constant current source (3 pin, 6.8mA typical-

ly), which is directly connected with the IC bias circuit, is

not available when pin 3 is OPEN (saturated).

(2)

Power dissipation

The allowable power dissipation is plotted against ambi-

ent temperature in Fig. 3.

FThermal derating curve

Toff=TBXC=

(V6CL

*VBEQ3) C6

4.12

105

C6 (sec) (Typ.)

6.8

µA (Typ.)

4VBE

S C6

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