其实数据手册有详细的介绍
Power-Down Reference Pin Operation
In addition to the power-down pin, the THS4275 also features a reference pin (REF) which allows the user to control the enable or disable power-down voltage levels applied to the PD pin. Operation of the reference pin as it relates to the power-down pin is described below.
In most split-supply applications, the reference pin is connected to ground. In some cases, the user may want to connect it to the negative or positive supply rail. In either case, the user needs to be aware of the voltage level thresholds that apply to the power-down pin. |