Technical Note
6/8
BD63821EFV, BD63823EFV
www.rohm.com
2012.02 - Rev.
© 2012 ROHM Co., Ltd. All rights reserved.
●Operation Notes
(1) Absolute maximum ratings
An excess in the absolute maximum ratings, 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 lines
As return of current regenerated by back EMF of FET output happens, take steps such as putting capacitor between
power supply and GND as an electric pathway for the regenerated current. Be sure that there is no problem with each
property such as emptied capacity at lower temperature regarding electrolytic capacitor to decide capacity value. If the
connected power supply does not have sufficient current absorption capacity, regenerative current will cause the voltage
on the power supply line to rise, which combined with the product and its peripheral circuitry may exceed the absolute
maximum ratings. It is recommended to implement a physical safety measure such as the insertion of a voltage clamp
diode between the power supply and GND pins.
(4) GND potential
The potential of GND pin must be minimum potential in all operating conditions.
(5) Metal on the backside (Define the side where product markings are printed as front)
The metal on the backside is shorted with the backside of IC chip therefore it should be connected to GND. Be aware that
there is a possibility of malfunction or destruction if it is shorted with any potential other than GND.
(6) Thermal design
Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
This IC exposes the metal on the backside of package. Note that this part is assumed to use after providing heat
dissipation treatment to improve heat dissipation efficiency. Try to occupy as wide as possible with heat dissipation
pattern not only on the board surface but also the backside.
(7) Inter-pin shorts and mounting errors
When attaching to a printed circuit board, pay close attention to the direction of the IC and displacement. Improper
attachment may lead to destruction of the IC. There is also possibility of destruction from short circuits which can be
caused by foreign matter entering between outputs or an output and the power supply or GND.
(8) Operation 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.
(9) ASO
When using the IC, set the output transistor so that it does not exceed absolute maximum ratings or ASO.
(10) Thermal shutdown circuit
The IC has a built-in thermal shutdown circuit (TSD circuit). If the chip temperature becomes Tjmax=150°C, and higher,
coil output to the motor will be open. The TSD circuit is designed only to shut the IC off to prevent runaway thermal
operation. It is not designed to protect or indemnify peripheral equipment. Do not use the TSD function to protect
peripheral equipment.
TSD on temperature [°C] (typ.) Hysteresis temperature [°C] (typ.)
175 25
(11) Over current protection circuit
The IC has a built-in over current protection circuit (OCP circuit). The OCP circuit is designed only to shut the IC off to
prevent abnormal situations, when absolute maximum output current is exceeded. It is not designed to protect or
indemnify peripheral equipment. Do not use the OCP function to protect peripheral equipment.
(12) Inspection of the application board
During inspection of the application board, if a capacitor is connected to a pin with low impedance there is a possibility
that it could cause stress to the IC, therefore an electrical discharge should be performed after each process. Also, as a
measure again electrostatic discharge, it should be earthed during the assembly process and special care should be
taken during transport or storage. Furthermore, when connecting to the jig during the inspection process, the power
supply should first be turned off and then removed before the inspection.
