BH□□RB1WGUT Series

Technical Note

7/8

www.rohm.com

2009.09 - Rev.B

© 2009 ROHM Co., Ltd. All rights reserved.

9.

GND voltage

The potential of GND pin must be minimum potential in all operating conditions.

10. Back Current

In applications where the IC may be exposed to back current flow, it is recommended to create a path to dissipate this

current by inserting a bypass diode between the VIN and VOUT pins.

11. Testing on application boards

When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to

stress. Always discharge capacitors after each process or step. Always turn the IC's power supply off before connecting

it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly steps as an

antistatic measure. Use similar precaution when transporting or storing the IC.

12. Regarding Input Pin of the IC (Fig.31)

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 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.

Fig. 30 Example Bypass Diode Connection

Fig. 31

Example of IC structure

VIN

STBY

GND

OUT

Back current

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

Parasitic

element

Pin B

Other adjacent elements

E

B

C

GND

Parasitic

element