TPS563200: why PWM switching start when EN>=1.1V

coulHi,

from datasheet as below, EN(high)=1.6V.

here is the test waveform from customer, VIN=12V, Vout=5V, yellow is EN, blue is Voutput, green is SW.

test result is when EN=1.1V(Y1 as below), here is SW(yellow line as below):

the sch is as below:

what will result in that? could you please help on that? thank you!

B&R

Yuan