BD8229EFV

10/13

TSZ02201-0H5H0BK01510-1-2

© 2015 ROHM Co., Ltd. All rights reserved.

04.Nov.2015 Rev.001

www.rohm.com

TSZ22111・15・001

Operational Notes

– continued

12.

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 2. Example of monolithic IC structure

13.

Area of Safe Operation (ASO)

Operate the IC such that the output voltage, output current, and power dissipation are all within the Area of Safe

Operation (ASO).

14.

Thermal Shutdown Circuit(TSD)

This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always

be within the IC’s power dissipation rating. If however the rating is exceeded for a continued period, the junction

temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all output pins. When the Tj falls below

the TSD threshold, the circuits are automatically restored to normal operation.

Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under no

circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from

heat damage.

15.

Capacitor Between Output and Ground

If a large capacitor is connected between the output pin and ground pin, current from the charged capacitor can flow

into the output pin and may destroy the IC when the VCC or IN pin is shorted to ground or pulled down to 0V. Use a

capacitor smaller than 0.1

μF between output and ground.

TSD ON temperature [°C] (typ)

Hysteresis temperature [°C] (typ)

175

25

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