SU8/16 GDU Low Side Pre-driver, PDE, question

[StanleyH]

Hi Support team,

  Customer is asking a question about the transition state of the low-side Pre-driver, PDE. Need your clarification.

RDs concern if the internal pull-down resistor affects their external circuit design. Thanks.

BTW, There is a typo in the RM register description(Rev. 5, 4/2017).  PDE is for low-side.

有兩個情況, 請確認:

1. MCU尚未醒來時(或 未上電時),40K pull-down有無作用? Datasheet上說明 MCU在 Reset時為1, Power on時,在哪個時間點才會將 PDE設為1 ?

2. 當 MCU工作電壓低於 LVD (Vcc<4.5V)點時, PDE是什麼狀態 ? 1 or 0? 是否依舊為1? 有無可能電壓低到某個值 , 或 MCU進入 Reset 狀態時, 會將PDE 設為0 (即 Disable內部 Pull-down 電阻) ?

yonggang.chen‌

[jonson_chen · Accepted solution]

Hi Stanley,

Please see the answers got from silicon designer:

1. MCU尚未醒來時(or未上電時),39K pull-down有無作用? Datasheet上說明MCU在Reset時為1, power on時,在哪個時間點才會將PDE設為1
• 未上電時,39K pull-down useless, because no power supply
After VDD supply >=4.5V, PDE will be set as 1

2. 當MCU工作電壓低到小於LVD (Vcc<4.5V)點時 , PDE是什麼狀態? 1 or 0? 是否依舊為1? 有無可能電壓低到某個值 or MCU進入Reset狀態時, 會將PDE 設為0(即disable內部pull-down 電阻)?
• High Voltage LDO voltage input range is 4.5V~18V, when VDD< 4.5V, LDO output is not stable. PDE status is unknown. 0 or 1 both possible.
This value can only be updated after reset is released. Can not change during reset.