请教ESD测试顺序

scy8080

在ESD测试时，有三种测试组合：I/O对电源/地、I/O对I/O、电源对地，这几种组合有没有测试顺序？比如说先测试电源对地，再测试I/O对电源/地，最后是IO对I/O。

wesleysungisme

In order to save test device, usually will do Power to Ground then IO to Power/Ground and the last is Io to IO.

The reason is:
# M. B; x+ t1 x4 M* m1 \1. If power to ground can not pass, the rest combination has less chance to pass
: |8 U) u$ @, [, L5 d- M2. Usually power pin count is less than IO pin count. It is fast to get an idea how the chip's ESD level
3. If failed, it's easy to find the failed ESD zapping combination

daidai

用相對I-V漂移故障判断方法时，是将电源地接到一起来，然后对I/O加电压，得到电流对电压的曲线.

daidai

Because all tests need to pass, so I think there is no fixed sequence. Normally, 电源对地 --> I/O对电源/地 --> I/O对I/O is recommended because this is general strength sequence of ESD immunity. For your reference.

scy8080

用相對I-V漂移故障判断方法时，I-V曲线又是如何得到的？是将电源地接到一起来，然后对I/O加电压，得到电流对电压的曲线，还是将其他的I/O和电源/地接到一起哪？
# y0 h9 i& J4 e; Y5 S, B  `对此比较困惑，望各位达人解惑，谢谢