Technical Note

13/15

BA6956AN, BA6287F, BA6285FS, BA6285AFP-Y, BA6920FP-Y

www.rohm.com

2009.04 - Rev.A

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c

2009 ROHM Co., Ltd. All rights reserved.



Interfaces

(BA6285FS, BA6285AFP-Y, BA6920FP-Y)

Fig. 38 FIN, RIN

Fig.39 POWER SAVE

(BA6956AN)

(BA6287F, BA6285FS, BA6285AFP-Y)

(BA6920FP-Y)

Fig. 40 VCC, VM, OUT1, OUT2, VREF, RNF, GND



Notes for use

1) Absolute maximum ratings

Devices may be destroyed when supply voltage or operating temperature exceeds the absolute maximum rating.

Because the cause of this damage cannot be identified as, for example, a short circuit or an open circuit, it is important

to consider circuit protection measures – such as adding fuses – if any value in excess of absolute maximum ratings is

to be implemented.

2) Connecting the power supply connector backward

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

connecting the power supply lines, such as adding an external direction diode.

3) Power supply lines

Return current generated by the motor’s Back-EMF requires countermeasures, such as providing a return current path

by inserting capacitors across the power supply and GND (10µF, ceramic capacitor is recommended). In this case, it is

important to conclusively confirm that none of the negative effects sometimes seen with electrolytic capacitors –

including a capacitance drop at low temperatures - occurs. Also, the connected power supply must have sufficient

current absorbing capability. Otherwise, the regenerated current will increase voltage on the power supply line, which

may in turn cause problems with the product, including peripheral circuits exceeding the absolute maximum rating. To

help protect against damage or degradation, physical safety measures should be taken, such as providing a voltage

clamping diode across the power supply and GND.

4) Electrical potential at GND

Keep the GND terminal potential to the minimum potential under any operating condition. In addition, check to

determine whether there is any terminal that provides voltage below GND, including the voltage during transient

phenomena. When both a small signal GND and high current GND are present, single-point grounding (at the set’s

reference point) is recommended, in order to separate the small signal and high current GND, and to ensure that

voltage changes due to the wiring resistance and high current do not affect the voltage at the small signal GND. In the

same way, care must be taken to avoid changes in the GND wire pattern in any external connected component.

5) Thermal design

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

conditions.

6) ASO - Area of Safety Operation

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

FIN

RIN

VM

VCC

OUT1

OUT2

RNF

VREF

VREF

VM

OUT1

OUT2

RNF

(GND, BA6287F)

VM

VCC

OUT1

OUT2

RNF

VREF

POWER

SAVE