运放的速度指标Slew rate和Rise time的区别？

魔双月壁

运放的速度指标Slew rate和Rise time的区别？ [复制链接]

手头有NE5532、NE5534;还有OP07、OP27、OP37。
做激光测距，现在需要一个能做成跟随器的高速运放。
看了一些手册发现Slew rate和Rise time这两个指标应该是反映运放速度的。但不确定具体应该看哪一个指标。

上图为NE5534的参数，SR为13V/us，也就是0到13V需要1us。但是上升时间确只有几十ns。哪一项反映速度？

上图为OP27的参数，只有SR，没有Slew rate！速度也太低了。

因为做激光测距，对运放的速度要求很高，1个ns的误差会造成距离出现30cm偏差。
现在需要一个高速运放做跟随器，不知道大家有没有什么高速运放芯片可以推荐的。

dragongtr

1ns是15cm的偏差。。。基本都没有搞清楚怎么做。。。

魔双月壁

dragongtr 发表于 2017-11-2 17:26
1ns是15cm的偏差。。。基本都没有搞清楚怎么做。。。

激光功率有限   漫反射时  APD互阻放大信号幅度比较低  目前测试用的是直射的

maychang

上图为NE5534的参数，SR为13V/us，也就是0到13V需要1us。但是上升时间确只有几十ns。哪一项反映速度？

都是反映速度的参数，但测试条件不同，也就是运放的工作状态不同。

xiaxingxing

They are two different ways of looking at the same thing.

Slew rate is a measure of how fast a signal is changing. How many volts it changes in a given period of time. Usually stated in volts per microsecond.

Rise time tells you how long it takes to get from 10% of the peak to 90% of the peak and ignores the beginning and end of the signal. If you had a signal that went from 0 to 10 volts, the rise time would be how long it took to get from 1 to 9 volts.

To use an automobile analogy: Slew rate would equal mph and rise tine would be the time it took to travel a certain distance. You can calculate one from the other.

Both are related to the maximum frequency a device can reproduce. If the slew rate is too low it will not be able to reproduce the higher frequencies. This is rarely a limiting factor in audio devices although some feel that the higher the slew rate the better the device.