BU64241GWZ Datasheet, PDF (18/24 Pages) Rohm – Linear Constant Current VCM Driver

BU64241GWZ
Datasheet
●Operational Notes
(1) Absolute maximum ratings
Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range
(Topr) may result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open
mode) when such damage is incurred. The implementation of a physical safety measure such as a fuse should be
considered when there is use of the IC in a special mode where it’s anticipated that the absolute maximum ratings
may be exceeded.
(2) Power supply lines
Regenerated current may flow as a result of the motor's back electromotive force. Insert capacitors between the
power supply and ground pins to serve as a route for regenerated current. Determine the capacitance based on of
all the characteristics of an electrolytic capacitor due to the electrolytic capacitor possibly losing some capacitance at
low temperatures. 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.
(3) Heat dissipation
Use a thermal design that allows for a sufficient margin regarding the power dissipation (Pd) during actual operating
conditions.
(4) Use in strong magnetic fields
Use caution when using the IC in the presence of a strong magnetic field as doing so may cause the IC to
malfunction.
(5) ASO
When using the IC, set the output transistor for the motor so that it does not exceed absolute maximum ratings or
ASO.
(6) Thermal shutdown circuit
This IC incorporates a TSD (thermal shutdown) circuit. If the temperature of the chip reaches the below
temperature, the motor coil output will be opened. The thermal shutdown circuit (TSD circuit) is designed only to
shut off the IC to prevent runaway thermal operation. It is not designed to protect the IC or to guarantee its
operation. Do not continue to use the IC after use of the TSD feature or use the IC in an environment where the its
assumed that the TSD feature will be used.
TSD ON temperature [°C]
(Typ.)
Hysteresis temperature [°C]
(Typ.)
150
20
(7) Ground Wiring Pattern
Ensure a minimum GND pin potential in all operating conditions.
When using GND patterns for both small signal and large currents, it is recommended to isolate the two ground
patterns by placing a single ground point at the application's reference point. This will help to alleviate noise in the
small signal ground voltage due to noise created by the ground pattern wiring resistance for large current blocks. Be
careful not to change the GND wiring pattern of any external components.
(8) Power Save (PS) terminal
PS holds the reset function on logic concurrently. Please release PS after the start-up of VCC. Reset is not normally
done when VCC is short-circuited to PS and it uses it, and there is a possibility of malfunctions.
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TSZ22111・15・001
18/20
TSZ02201-0H2H0B600460-1-2
01. Jul. 2013 Rev.004