These pins cannot go 0.3 V above GATEVCC. If GATEVCC is 10 V, then these pins cannot exceed 10.3V. For TG, this is with respect to switchnode. For BG, this is with respect to GND.
Hi Mochi,Sorry for not responding. I didn't see this.I'm not sure what you mean +/- 0.3 V with respect to bias. TG and BG are outputs. Note 3 specifically says that you cannot apply a voltage to these pins. The TG outputs float and are with respect to SWx. The TG outputs swing from SWx to GATEVCC - SWx. The BG outputs are GND referenced. The BG outputs switch from GND to GATEVCC.Now it is possible if you have a really bad layout or use leaded MOSFETs to have a lot of inductance on the TG or BG traces. This could cause the pins to ring above GATEVCC or ring below their respective reference. This needs to be prevented. The layout needs to be carefully done to prevent this. I hope that this answers your question.