BD37Axx Series

BD87Axx Series

BD99A41F

Datasheet

Operational Notes – continued

11.

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 the P layers with the N layers of other elements, creating a

parasitic diode or transistor. For example (refer to figure below):

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, operational faults, or physical damage. Therefore, conditions that cause these diodes to

operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should

be avoided.

Figure 18. Example of monolithic IC structure

12.

Applications or inspection processes with modes where the potentials of the VDD pin and other pins may be reversed

from their normal states may cause damage to the IC’s internal circuitry or elements. Use an output pin capacitance

of 1000 µF or lower in case VDD is shorted with the GND pin while the external capacitor is charged. It is

recommended to insert a diode for preventing back current flow in series with VDD or bypass diodes between VDD

and each pin.

Figure 19.

13.

When VDD falls below the operating marginal voltage, output will be open. When output is being pulled up to input,

output will be equivalent to VDD.

14.

Regarding the CLK and INH pins

The CLK and INH pins comprise inverter gates and should not be left open. (These pins should be either pulled up or

down.) Input to the CLK pin is detected using a positive edge trigger and does not affect the CLK signal duty. Input

Bypass diode

VDD

Back current prevention diode

Pin

N

N

P

+

P

N

N

P

+

P Substrate

GND

N

P

+

N

N

P

+

N P

P Substrate

GND

GND

Parasitic

Elements

Pin A

Pin A

Pin B

Pin B

B

C

E

Parasitic

Elements

GND

Parasitic

Elements

C

B

E

Transistor (NPN)

Resistor

N Region

close-by

Parasitic

Elements

11/15

TSZ02201-0G1G0AN00130-1-2

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05.Sep.2014 Rev.003

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TSZ22111・15・001