Technical Note
9/11
BA6247FP-Y,BA6238A
www.rohm.com
2011.05 - Rev.B
© 2011 ROHM Co., Ltd. All rights reserved.
●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) 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) Operation in strong electromagnetic fields
Using this product in strong electromagnetic fields may cause IC malfunctions. Use extreme caution with
electromagnetic fields.
8) ASO - Area of Safety Operation
When using the IC, set the output transistor so that it does not exceed absolute maximum ratings or ASO.
9) Built-in thermal shutdown (TSD) circuit
The TSD circuit is designed only to shut the IC off - when BA6238A driver outputs low - to prevent thermal runaway. It
is not designed to protect the IC or guarantee its operation in the presence of extreme heat. Do not continue to use the
IC after the TSD circuit is activated, and do not operate the IC in an environment where activation of the circuit is
assumed.
BA6247FP-Y BA6238A
T
ON
[℃] 170 150
T
HYS
[℃] 30 50
*All temperature values are typical.
10) Capacitor between output and GND
In the event a large capacitor is connected between the output and GND, if VCC and VIN are short-circuited with 0V or
GND for any reason, the current charged in the capacitor flows into the output and may destroy the IC. Use a capacitor
smaller than 1μF between output and GND.
