Other Parts Discussed in Thread: TPS3808,
产品手册第13页, “The track input has its own internal pull-up to a potential of 5 V to 13.2 V The input is not compatible with TTL logic devices. An
open-collector (or open-drain) discrete transistor or supply voltage supervisor (TPS3808 or TPS7712) is recommended for control”
拟采用TPS3808控制,TPS3808的RESET输出脚为低电平有效,为Open Drain, 且TPS3808规定RESET的极限值是7V。我在疑惑TPS3808的RESET能否直接连接PTH12050L的Track脚。手册说“the track input has its own internal pull-up to a potential of 5 V to 13.2 V”,超过7V就超出了TPS3808的RESET的极限值了。
而且我不明白为什么是 track 内部上拉到 5 V to 13.2 V?是不是上拉到PTH12050L的VI 脚?但是根据产品手册VI 的范围是10.8V-13.2V, 5V是怎么出来的?
关于Open Drain输出,产品手册说了极限电压,但是实际连接时,是连了一个电阻,再连接高电压的(例如12V),这样如果Open Drain脚处于高阻态,无电流流过,那么该Open Drain管脚仍会承受12V电压。超出了极限值,是不是仍然是违规的(尽管有电阻的存在)?
如果要采用TPS3808,应该如何设计电路?