BA6908F View Datasheet(PDF) - ROHM Semiconductor

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BA6908F

Single-Phase Full-Wave Motor Driver for Fan Motor

ROHM Semiconductor 

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〇Cautions on use

1) Absolute maximum ratings

An excess in the absolute maximum rations, such as supply voltage, temperature range of operating conditions, etc.,

can break down the devices, thus making impossible to identify breaking mode, such as a short circuit or an open

circuit. If any over rated values will expect to exceed the absolute maximum ratings, consider adding circuit

protection devices, such as fuses.

2) Connecting the power supply connector backward

Connecting of the power supply in reverse polarity can damage IC. Take precautions when connecting the power

supply lines. An external direction diode can be added.

3) Power supply line

Back electromotive force causes regenerated current to power supply line, therefore take a measure such as placing

a capacitor between power supply and GND for routing regenerated current. And fully ensure that the capacitor

characteristics have no problem before determine a capacitor value. (when applying electrolytic capacitors,

capacitance characteristic values are reduced at low temperatures)

4) GND potential

The potential of GND pin must be minimum potential in all operating conditions. Also ensure that all terminals except

GND terminal do not fall below GND voltage including transient characteristics. However, it is possible that the motor

output terminal may deflect below GND because of influence by back electromotive force of motor. Malfunction may

possibly occur depending on use condition, environment, and property of individual motor. Please make fully

confirmation that no problem is found on operation of IC.

5) Thermal design

Use a thermal design that allows for a sufficient margin in light of the power dissipation(Pd) in actual operating

conditions.

6) Inter-pin shorts and mounting errors

Use caution when positioning the IC for mounting on printed circuit boards. The IC may be damaged if there is any

connection error or if pins are shorted together.

7) Actions in strong electromagnetic field

Use caution when using the IC in the presence of a strong electromagnetic field as doing so may cause the IC to

malfunction.

8) ASO

When using the IC, set the output transistor so that it does not exceed absolute maximum rations or ASO.

9) Thermal shut down circuit

The IC incorporates a built-in thermal shutdown circuit (TSD circuit). Operation temperature is 175℃(typ.) and has a

hysteresis width of 25℃(typ.). When IC chip temperature rises and TSD circuit works, the output terminal becomes

an open state. TSD circuit is designed only to shut the IC off to prevent thermal runaway. It is not designed to protect

the IC or guarantee its operation. Do not continue to use the IC after operation this circuit or use the IC in an

environment where the operation of this circuit is assumed.

10) Testing on application boards

When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to

stress. Always discharge capacitors after each process or step. Always turn the IC’s power supply off before

connecting it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly

steps as an antistatic measure. Use similar precaution when transporting or storing the IC.

11) GND wiring pattern

When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns,

placing a single ground point at the ground potential of application so that the pattern wiring resistance and voltage

variations caused by large currents do not cause variations in the small signal ground voltage. Be careful not to

change the GND wiring pattern of any external components, either.

12) Capacitor between output and GND

When a large capacitor is connected between output and GND, if Vcc is shorted with 0V or GND for some cause, it

is possible that the current charged in the capacitor may flow into the output resulting in destruction. Keep the

capacitor between output and GND below 100uF.

13) IC terminal input

When Vcc voltage is not applied to IC, do not apply voltage to each input terminal. When voltage above Vcc or below

GND is applied to the input terminal, parasitic element is actuated due to the structure of IC. Operation of parasitic

element causes mutual interference between circuits, resulting in malfunction as well as destruction in the last. Do

not use in a manner where parasitic element is actuated.

REV. D

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