Make sure that the connection to the VDD pin is low impedance. Good analog design practice recommends placing a minimum 0.1-µF ceramic capacitor as near as possible to the VDD pin to GND. If using the TPS3838 variant, be sure to follow the Recommended Operating Conditions to determine the pullup resistor value. Larger transients and faster slew rates on VDD should use larger input capacitors. If not using MR, tie to VDD to reduce current consumption.