How to use the MB3771 reset IC

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NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
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Hello,

I have a question about how to use the reset IC.

VCC (power supply voltage) and VS (detection voltage) are about 6V, and about 15V is supplied to the RESET pin by external pull-up.

Is there no problem with this usage?

Part Number : MB3771PFER

Best Regards,

Naoaki Morimoto

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1 Solution

森本様

先のスレッド6のご質問内容は、「元々はVcc=6V、RESET端子は別電源から15Vにプルアップする使い方を想定している。この使い方でデバイスは破壊するか」と認識いたしました。(誤認あればご指摘ください。)

回答:

IC破壊・誤動作の可能性がございます。RESET端子を外部プルアップする場合はVccへのプルアップを推奨いたします。

鶴丸

View solution in original post

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10 Replies
Takashi_M
Moderator
Moderator
Moderator
1000 replies posted 500 solutions authored 750 replies posted

Morimoto-san,

Could you please let us know what the background of this thread is?

Because, this is EOL product and not to be recommended to use.

Thank you.

this is EOL product and not to be recommended to use

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NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

Hello,

We will not use it for new products, but we will use it for maintenance purposes, so we have confirmed that there is no problem.

Best Regards,

Naoaki Morimoto

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AtsushiT_61
Employee
Employee
5 sign-ins 10 replies posted 5 replies posted

Hi, Morimoto san

When you use external pull-up, the RESET pin is recommended to be pull-up to the Vcc pin.

Thanks, Tsurumaru

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NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

Hello Tsurumaru-san,

Thank you for the reply.

It means that a voltage higher than Vcc should not be applied to the RESET pin.

Best Regards,

Naoaki Morimoto

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Basically, the RESET pin don't require external pull up because the RESET pin is pull up internally to the Vcc.
In the case of using external pull up, it is recommended to pull up to the Vcc pin.

Also, please chose the appropriate pull up resister not to exceed the sink current 20 mA to the RESET pin.

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NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

Hello Tsurumaru-san,

Thank you for explain.

Customers agreed to connect to Vcc when using an external pull-up.

However, if Vcc = 6V, external pull-up voltage = 15V, will it break the device?

I did not understand the DC maximum rating of the RESET pin in the data sheet.

Best Regards,

Naoaki Morimoto

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Morimoto san

申し訳ありませんが、回路接続状況を補足いただけないでしょうか。

RESET端子をVCCにpull upしていただけるとのことですが、Vcc=6V時に(VCC=external pull-up voltage)が15Vになるという事でしょうか。

鶴丸

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NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

鶴丸様

元々はVcc=6V、RESET端子は別電源から15Vにプルアップする使い方を想定していました。

本ケースの回答を持って、プルアップの15VはVcc接続に変更するように回答しています。

高耐圧の端子でない限りVcc以上の電位をかける事は禁止だと思いますので、その点だけ確認させてください。

よろしくお願いいたします。

森本

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森本様

先のスレッド6のご質問内容は、「元々はVcc=6V、RESET端子は別電源から15Vにプルアップする使い方を想定している。この使い方でデバイスは破壊するか」と認識いたしました。(誤認あればご指摘ください。)

回答:

IC破壊・誤動作の可能性がございます。RESET端子を外部プルアップする場合はVccへのプルアップを推奨いたします。

鶴丸

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NaMo_1534561
Level 5
Level 5
Distributor - Macnica (Japan)
100 replies posted 100 sign-ins 50 replies posted

鶴丸様

ありがとうございました。本件クローズいたします。

森本

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