带宽增益积的理解

关于带宽增益积，我的理解是放大器带宽和带宽增益的乘积是一个定值。按照我的理解，OPA657的带宽增益积是1600MHz，当增益G=10时，带宽应该为160MHz，可是Datasheet上说明的是275MHz，我该怎么理解？

谢谢大家！

其实这点在OPA657的datasheet Page 18中“频响控制”部分有详细的介绍，可以参考下，如有问题，可以继续讨论。

Ideally, dividing GBP by the noninverting signal gain (also called the noise gain, or NG) predicts the closed-loop bandwidth. In practice, this only holds true when the phase margin approaches 90°, as it does in high-gain configurations. At low gains (increased feedback factors), most high-speed amplifiers exhibit a more complex response with lower phase margin.