bd9134muv ROHM Co. Ltd., bd9134muv Datasheet - Page 14

• Manufacturer Part Number: bd9134muv
• Description: Step-down Switching Regulator
• Manufacturer: ROHM Co. Ltd.

●Cautions on use
1. Absolute Maximum Ratings
2. Electrical potential at GND
3. Short-circuiting between terminals, and mismounting
4. Thermal shutdown protection circuit
5. Inspection with the IC set to a pc board
6. Input to IC terminals
This is a monolithic IC with P
N-layer of each element form a P-N junction, and various parasitic element are formed.
The structure of the IC inevitably forms parasitic elements, the activation of which may cause interference among circuits,
and/or malfunctions contributing to breakdown. It is therefore requested to take care not to use the device in such manner
that the voltage lower than GND (at P-substrate) may be applied to the input terminal, which may result in activation of
parasitic elements.
While utmost care is taken to quality control of this product, any application that may exceed some of the absolute maximum
ratings including the voltage applied and the operating temperature range may result in breakage. If broken, short-mode
or open-mode may not be identified. So if it is expected to encounter with special mode that may exceed the absolute
maximum ratings, it is requested to take necessary safety measures physically including insertion of fuses.
GND must be designed to have the lowest electrical potential In any operating conditions.
When mounting to pc board, care must be taken to avoid mistake in its orientation and alignment. Failure to do so may
result in IC breakdown. Short-circuiting due to foreign matters entered between output terminals, or between output and
power supply or GND may also cause breakdown.
Thermal shutdown protection circuit is the circuit designed to isolate the IC from thermal runaway, and not intended to
protect and guarantee the IC. So, the IC the thermal shutdown protection circuit of which is once activated should not be
used thereafter for any operation originally intended.
If a capacitor must be connected to the pin of lower impedance during inspection with the IC set to a pc board, the capacitor
must be discharged after each process to avoid stress to the IC. For electrostatic protection, provide proper grounding to
assembling processes with special care taken in handling and storage. When connecting to jigs in the inspection process,
be sure to turn OFF the power supply before it is connected and removed.
If a resistor is joined to a transistor terminal as shown in Fig 37.
Parasitic element
○if GND>Terminal B (at NPN transistor side),
○P-N junction works as a parasitic diode if the following relationship is satisfied; GND>Terminal A (at resistor side), or
Pin A
GND>Terminal B (at transistor side); and
a parasitic NPN transistor is activated by N-layer of other element adjacent to the above-mentioned parasitic diode.
N
P
+
N
GND
P
P substrate
P
+
+
isolation between P-substrate and each element as illustrated below. This P-layer and the
N
Resistor
Pin A
Fig.35 Simplified structure of monorisic IC
Parasitic
element
Parasitic element
14/15
Pin B
N
P
+
C
B
N
E
GND
P
P substrate
Transistor (NPN)
P
+
N
GND
Other adjacent elements
Pin B
B
C
E
GND
Parasitic
element