bd67929efv ROHM Co. Ltd., bd67929efv Datasheet - Page 7

• Manufacturer Part Number: bd67929efv
• Description: Three-phase Brushless Motor Driver For Polygonal Mirrors [for Lbp, Ppc]
• Manufacturer: ROHM Co. Ltd.

BD67929EFV
© 2010 ROHM Co., Ltd. All rights reserved.
www.rohm.com
○GND/Ground terminal
○VCC/Power supply terminal
○RNF/Connection terminal of resistor for detecting of output current
○IC back side metal/Metal for heat-radiation
○TEST terminal/Terminal for testing
In order to reduce the noise caused by switching current and to stabilize the internal reference voltage of IC, please wire
in such a way that the wiring impedance from this terminal is made as low as possible to achieve the lowest electrical
potential no matter what operating state it may be.
Motor's drive current is flowing in it, so please wire in such a way that the wire is thick & short and has low impedance.
Voltage VCC may have great fluctuation, so please arrange the bypass capacitor of about 47µF～470µF as close to the
terminal as possible and adjust in such a way that the voltage VCC is stable. Please increase the capacity if needed
especially when a large current is used or those motors that have great back electromotive force are used. In addition, for
the purpose of reducing of power supply's impedance in wide frequency bandwidth, parallel connection of multi-layered
ceramic capacitor of 0.01µF～0.1µF etc. is recommended. Extreme care must be used to make sure that the voltage
VCC does not exceed the rating even for a moment. Still more, in the power supply terminal, there is built-in clamp
component for preventing of electrostatic destruction. If steep pulse or voltage of surge more that maximum absolute
rating is applied, this clamp component operates, as a result there is the danger of destruction, so please be sure that the
maximum absolute rating must not be exceeded. It is effective to mount a Zener diode of about the maximum absolute
rating. Moreover, the diode for preventing of electrostatic destruction if reverse voltage is applied between V
and GND terminal, so please be careful.
Please connect the resistor of 0.25Ω～1.00Ω for current detection between this terminal and GND. In view of the power
consumption of the current-detecting resistor, please determine the resistor in such a way that W=I
exceed the power dissipation of the resistor. In addition, please wire in such a way that it has a low impedance and does
not have a impedance in common with other GND patterns because motor's drive current flows in the pattern through
RNF terminal～current-detecting resistor～GND. Please do not exceed the rating because there is the possibility of
circuits' malfunction etc. if RNF voltage has exceeded the maximum rating (0.7V). Moreover, please be careful because if
RNF terminal is shorted to GND, large current flows without normal PWM constant current control, then there is the
danger that OCP or TSD will operate. If RNF terminal is open, then there is the possibility of such malfunction as output
current does not flow either, so please do not let it open.
For HTSSOP-B28 package, the heat-radiating metal is mounted on IC's back side, and on the metal the heat-radiating
treatment is performed when in use, which becomes the precondition to use, so please secure sufficiently the
heat-radiating area by surely connecting by solder with the GND plane on the board and getting as wide GND pattern as
possible. Please be careful because the allowable loss as shown in page 21 cannot be secured if not connected by
solder. Moreover, the back side metal is shorted with IC chip's back side and becomes the GND potential, so there is the
danger of malfunction and destruction if shorted with potentials other than GND, therefore please absolutely do not
design patterns other than GND through the IC's back side.
This is the terminal used at the time of shipping test. Please connect to GND. Please be careful because there is a
possibility of malfunction if GND unconnected.
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OUT
Technical Note
2010.12 - Rev.A
2
・R[W] does not
CC
terminal