Technical Note

9/10

BA6950FS, BA6951FS

www.rohm.com

2011.05 - Rev.C

© 2011 ROHM Co., Ltd. All rights reserved.

13) Regarding the 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, 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 inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual

interference among circuits, as well as operating malfunctions and physical damage. Therefore, do not use methods by

which parasitic diodes operate, such as applying a voltage lower than the GND (P substrate) voltage to an input pin.

Parasitic

element

Appendix: Example of monolithic IC structure

Resistor

Transistor (NPN)

N

N

N

P

+

P

+

P

P substrate

GND

Parasitic element

Pin A

N

N

P

+

P

+

P

P substrate

GND

Parasitic element

Pin B

C

B

E

N

GND

Pin A

Pin B

Other adjacent elements

E

B

C

GND

Parasitic

element