I am using an NPN transistor (SBF720T1G) along with the drive pin to generate the Vreg (5V). But the voltage being generated at the Vreg pin is around 0.16V. When I probe the drive signal using an oscilloscope I am mostly getting only noise, as shown below
Please go through this thread https://ez.analog.com/power/battery-management-system/f/qa/166926/communication-issue-with-ltc6813
The answer to this thread might help you.