Technical Note

6/11

BA6247FP-Y,BA6238A

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2011.05 - Rev.B

© 2011 ROHM Co., Ltd. All rights reserved.

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External application components

1) Resistor for the current limitation, R1

This is a current limiting resistor for collector loss reduction and at the time of short-circuited output. It depends on the

power supply voltage used, etc., but choose resistance of about 5 to 10Ω. In addition, set resistance with utmost care

to voltage drop caused by inrush current that flows when the motor is started.

2) Resistors and zener diode for the output high voltage setting, R2, R3 and ZD

These are the resistors and zener diode used when output high voltage is set. Zener diode ZD is recommended to be

used instead of resistor R3 when the power supply voltage is unstable.

3) Stabilization capacitor for the power supply line, C1

Please connect the capacitor of 1μF to 100μF for the stabilization of the power supply line, and confirm the motor

operation.

4) Phase compensating capacitor, C2, C3, C4, C5

Noise is generated in output pins or oscillation results in accord with the set mounting state such as power supply

circuit, motor characteristics, PCB pattern artwork, etc. As noise oscillation measures, connect 0.01μF to 0.1μF

capacitors.

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Functional descriptions

1) Operation modes

Table 3 Logic table, BA6247FP-Y / BA6238A

IN1

IN2

IN3

OUT1

OUT2

OUT3

OPERATION

L

L

L

L

L

L

Brake (stop)

H

H

L

L

H

L

OPEN*

Motor 1, forward (OUT1 > OUT2)

H

L

H

OPEN*

Motor 1, reverse (OUT2 > OUT1)

L

H

L

H

OPEN*

L

Motor 2, forward (OUT1 > OUT3)

H

L

OPEN*

H

Motor 2, reverse (OUT3 > OUT1)

H

H

L

L

L

L

Brake (stop)

H

* OPEN is the off state of all output transistors. Please note that this is the state of the connected diodes,

which differs from that of the mechanical relay.