BA5954FM View Datasheet(PDF) - ROHM Semiconductor

Part Name

Description

Manufacturer

BA5954FM

BLT Driver For DVD-ROM

ROHM Semiconductor 

4/5

{ CAUTIONS ON USE

(1) Setting the Standby terminal to open or 0.5V or less allows the circuit current to be set in the standby mode.

Under conditions of normal use, the Standby terminal should be pulled-up to 2.0V or above.

(2) When the power supply voltage (Vcc) drops to 3.5V (Typ.) or less, the mute function will be activated and,

when recovering to 3.7V (Typ.) or above, the circuit will startup again.

(3) On the Bias terminal, the applied voltage of 0.9V (Typ.) or less will activate a mute function. Under

conditions of normal use, It should be set to 12V or above.

(4) About absolute maximum ratings

Exceeding the absolute maximum ratings, such as the applied voltage or the operating temperature range,

may cause permanent device damage. As these cases cannot be limited to the broken short mode or the

open mode, if a special mode where the absolute maximum ratings may be exceeded is assumed, it is

recommended to take mechanical safety measures such as attaching fuses.

(5) About power supply lines

As a measure against the back current regenerated by a counter electromotive force of the motor, a

capacitor to be used as a regenerated-current path can be installed between the power supply and GND

and its capacitance value should be determined after careful check that any problems, for example, a leak

capacitance of the electrolytic capacitor at low temperature, are not found in various characteristics.

(6) About GND potential

The electric potential of the GND terminal must be kept lowest in the circuitry at any operation states.

(7) About thermal design

With consideration of the power dissipation (Pd) under conditions of actual use, a thermal design provided

with an enough margin should be done.

(8) About operations in a strong electric field

When used in a strong electric field, note that a malfunction may occur.

(9) ASO

When using this IC, the output Tr. must be set not to exceed the values specified in the absolute maximum

ratings and ASO.

(10) Thermal shutdown circuit (Thermal shutdown: TSD)

This IC incorporates a thermal shutdown circuit (TSD circuit). When the chip temperature reaches the

value shown below, the coil output to the motor will be set to open.

The thermal shutdown circuit is designed only to shut off the IC from a thermal runaway and not intended

to protect or guarantee the entire IC functions.

Therefore, users cannot assume that the TSD circuit once activated can be used continuously in the

subsequent operations.

TSD ON Temperature

[°C] (typ.)

175

Hysteresis Temperature

[°C] (typ.)

25

(11) About earth wiring patterns

When a small signal GND and a large current GND are provided, it is recommended that the large current

GND pattern and the small signal GND pattern should be separated and grounded at a single point of the

reference point of the set in order to prevent the voltage of the small signal GND from being affected by a

voltage change caused by the resistance of the pattern wiring and the large current.

Make sure that the GND wiring patterns of the external components will not change, too.

(12) This IC is a monolithic IC which has a P+ isolations and P substrate to isolate elements each other.

This P layer and an N layer in each element form a PN junction to construct various parasitic elements.

Due to the IC structure, the parasitic elements are inevitably created by the potential relationship.

Activation of the parasitic elements can cause interference between circuits and may result in a

malfunction or, consequently, a fatal damage. Therefore, make sure that the IC must not be used under

conditions that may activate the parasitic elements, for example, applying the lower voltage than the

ground level (GND, P substrate) to the input terminals.

In addition, do not apply the voltage to input terminals without applying the power supply voltage to the IC.

Also while applying the power supply voltage, the voltage of each input terminal must not be over the

power supply voltage, or within the guaranteed values in the electric characteristics.

REV. A

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