Hi Sirs,
According to datasheet, it’s better for adding RF/10ohm, CF/0.1uF and 0.1uF MLCC from IN+/IN- to GND.
But in fact we don't.
May i know any risk if we didn't add it?
Thanks!!
Hi Sirs,
According to datasheet, it’s better for adding RF/10ohm, CF/0.1uF and 0.1uF MLCC from IN+/IN- to GND.
But in fact we don't.
May i know any risk if we didn't add it?
Thanks!!
Hello Shu-Cheng,
Having the RF and CF input filter (first figure) is important if you need to filter out high frequency noise or signal spikes where the common-mode voltage (Vcm) is not exceeding 26V. This will help create a cleaner output signal from the INA199. You can learn more about how to design these input filters here. If you don't have this filter you risk having a potentially more noisey output voltage signal.
The second image you have (Figure 26) is important if you expect your device to see large and fast input transients where the Vcm > 26V. This external filter is only meant attenuate these large transients so they do not reach the internal ESD (electric static discharge) diodes of the INA199 (Version A) because if they do this will cause a latch-up condition. With a potential latch-up, you risk losing your Vout signal and potentially damaging your device.There are other ways to protect the device from latch-up, such as using TVS diodes. You can read more about how to implement this here.
Additionally, we versions B and C for the INA199, which have improved internal ESD structures. You can read more about these devices in the INA199 datasheet here:
Please let me know if you have more questions.
Peter Iliya
Current Sense Applications