BH6578FVM,BD7931F

Technical Note

6/8

www.rohm.com

2009.06 - Rev.A

© 2009 ROHM Co., Ltd. All rights reserved.

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Cautions on use

(1) Absolute maximum ratings

In the event that applied voltage (VCC, VM), working temperature range (Topr), and other absolute maximum rating are

exceeded, the IC may be destroyed. Because it is unable to identify the short-circuit mode, open mode, etc., if any

special mode is assumed, which exceeds the absolute maximum rating, physical safety measures are requested to be

taken, such as fuses, etc.

(2) Reverse connection of power supply connector

Reverse connection of power supply connector may destroy the IC. Take necessary measures to protect the IC from

reverse connection breakage such as externally inserting diodes across power supply and IC power supply terminal as

well as across power supply and motor coil.

(3) Power supply line

Because return of current regenerated by reverse EMF of a motor occurs, take necessary measures such as inserting

capacitors across the power supply and GND as a path for regenerated current, and determine the capacity value after

thoroughly confirming that there would be no problems in various characteristics such as capacitance drop at low

temperature which may occur with electrolytic capacitors.

(4) Ground potential

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

actually any terminal which provides voltage below GND including transient phenomena.

(5) Thermal design

Consider permissible dissipation (Pd) under actual working condition and carry out thermal design with sufficient margin

provided.

(6) Terminal-to-terminal short-circuit and erroneous mounting

When the present IC is mounted to a printed circuit board, take utmost care to direction of IC and displacement. In the

event that the IC is mounted erroneously, IC may be destroyed. In the event of short-circuit caused by foreign matter

that enters in a clearance between outputs or output and power-GND, the IC may be destroyed.

(7) Operation in strong electromagnetic field

The use of the present IC in the strong electromagnetic field may result in maloperation, to which care must be taken.

(8) ASO

When IC is used, design in such a manner that the output transistor to a motor does not exceed absolute maximum

ratings and ASO.

(9) Thermal shutdown circuit (TSD) (common)

When junction temperature (Tj) becomes thermal shutdown ON temperature 175°C, the thermal shutdown circuit (TSD

circuit) is activated and driver output current is shorted. There is 25°C temperature hysteresis. The thermal shutdown

protection circuit is first and foremost intended for interrupt IC from thermal runaway, and is not intended to protect and

warrant the IC. Consequently, never attempt to continuously use the IC after this circuit is activated or to use the circuit

with the activation of the circuit premised.

(10) Capacitor across output and GND

In the event a large capacitor is connected across output and GND, when Vcc and VIN are short-circuited with 0V or

GND for some kind of reasons, current charged in the capacitor flows into the output and may destroy the IC. Use a

capacitor smaller than 0.1 µF between output and GND.

(11) Inspection by set substrate

In the event a capacitor is connected to a pin with low impedance at the time of inspection with a set substrate, there is a

fear of applying stress to the IC. Therefore, be sure to discharge electricity for every process. Furthermore, when the

set substrate is connected to a jig in the inspection process, be sure to turn OFF power supply to connect the jig and be

sure to turn OFF power supply to remove the jig. As electrostatic measures, provide grounding in the assembly

process, and take utmost care in transportation and storage.