OPA1632的第7脚的作用是什么？
按照数据表的说明：
7.4.1 Shutdown Function
The shutdown (enable) function of the OPA1632 is referenced to the negative supply of the operational amplifier.
A valid logic low (< 0.8 V above negative supply) applied to the enable pin (pin 7) disables the amplifier output.
Voltages applied to pin 7 that are greater than 2 V above the negative supply place the amplifier output in an
active state, and the device is enabled. If pin 7 is left disconnected, an internal pull-up resistor enables the
device. Turn-on and turn-off times are approximately 2 μs each.
Quiescent current is reduced to approximately 0.85 mA when the amplifier is disabled. When disabled, the output
stage is not in a high-impedance state. Thus, the shutdown function cannot be used to create a multiplexed
switching function in series with multiple amplifiers.
我理解为当第7脚电压<0.8V时是禁止放大器输出的，因此如此设计一款电路：
OPA1632的第7脚连接一个开关（S1）到地，作为静音开关。
但实际使用中S1的开关对1632没有任何作用，实测S1开时第7脚14.94V、S1闭合时第7脚0V，在这两种状态下1632的输入、输出波形没有任何变化，是何原因？
