For MB95F633K, some questions about treatment of unused pins

[JuIn_1625121]

1)

For MB95F633K, the customer is considering to set unused pin to the output state, Low, and leave it unconnected.

He does not know the tests and criteria to see if there is any problem with this treatment.

I don't know too,

But I think there is no problem if it passes his normally environmental test.

Is it correct?

Are there any concerns?

2)

If he set unused pin to the output state, Low, and connected 100kΩ to GND,

I think there is no problem.

Is it correct?

Best Regards,

Inoue

[Anonymous · Accepted solution]

Hello Inoue-san

You can refer to the datasheet page 18 of 103 regarding how to treat the unused pin. There should be no problem if customer follow this guideline.

http://www.cypress.com/file/250436/download

9. Pin Connection

• Treatment of unused pins If an unused input pin is left unconnected, a component may be permanently damaged due to malfunctions or latchups. Always pull up or pull down an unused input pin through a resistor of at least 2 kΩ. Set an unused input/output pin to the output state and leave it unconnected, or set it to the input state and treat it the same as an unused input pin. If there is an unused output pin, leave it unconnected.

• 未使用端子の処理 入力に用いる未使用端子を開放のままにしておくと , 誤動作およびラッチアップ現象による永久破壊の原因になることがあり ます。使用していない入力端子は 2 kΩ 以上の抵抗を介してプルアップまたはプルダウンの処理をしてください。使用していな い入出力端子は , 出力状態に設定して開放とするか , 入力状態に設定して入力端子と同じ処理をしてください。使用していない 出力端子は , 開放としてください。

Hope this help.

Thanks,

Nada

[JuIn_1625121]

HI Nada,

Thank you for your answer.

He knows that guideline,.

But he asks about problem with pull down at 100 kΩ.If there is a problem, could you tell me what is the problem?

Best Regards,

Inoue

[Anonymous]

Hi Inoue-san

If you use 100kΩ, you can reduce power consumption. But rising time will become long. You need to evaluate whether the rise time is appropriate or not.

[JuIn_1625121]

Hi Yoshioka-san,

OK, I understood your answer.

Thank you.

Best Regards,

Inoue