BU90030G Datasheet, PDF (4/5 Pages) Rohm – Silicon Monolithic Integrated Circuit

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1.) Absolute maximum ratings
An excess in the absolute maximum rating, 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.) GND voltage
The potential of GND pin must be minimum potential in all condition. As an exception, the circuit design allows voltages
up to -0.3 V to be applied to the IC pin.
3.) Thermal design
Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions
4.) Inter-pin shorts and mounting errors
Use caution when positioning the IC for mounting on printed circuit boards. The IC may be damaged if there is any
connection error or if pins are shorted together.
5.) Actions 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
6.) Mutual impedance
Power supply and ground wiring should reflect consideration of the need to lower mutual impedance and minimize ripple
as much as possible (by making wiring as short and thick as possible or rejecting ripple by incorporating inductance
and capacitance).
7.) Regarding input pin of the IC
This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated.
P-N junctions are formed at the intersection of these P layers with the N layers of other elements, creating a parasitic diode
or transistor. For example, as shown in the figures below, the relation between each potential is as follows:
When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode.
When GND > Pin B, the P-N junction operates as a parasitic transistor.
Parasitic diodes can occur inevitable in the structure of the IC. The operation of parasitic diodes can result in
mutual interference among circuits, operational faults, or physical damage. Accordingly, methods by which parasitic diodes
operate, such as applying a voltage that is lower than the GND (P substrate) voltage to an input pin, should not be used.
8.) Thermal shutdown Circuit (TSD Circuit)
This model IC has a built-in TSD circuit. This circuit is only to cut off the IC from thermal runaway, and has not been
design to protect or guarantee the IC. Therefore, the user should not plan to activate this circuit with continued operation
in mind.
9.) External Component
Use a small ESR ceramic capacitor for the external capacitor (CIN,COUT,Cfly) and set them nearby IC.
Use the CIN capacitor’s value that meets this condition ( CIN≧COUT ).
And Use the Cfly capacitor’s value that meets this condition ( Cfly≦COUT ).
There may be a case that it doesn’t achieve the objective characteristic because the capacity come down lower than the
normal capacitor because of the bias voltage and the temperature when using a small layered ceramic capacitor.
Therefore, the user should use it after checking the DC bias capacity and other characteristics.
REV. Ａ