The PM6644 from STMicroelectronics is a buck switching regulator Integrated Circuit with positive adjustable output at 0.9 V or fixed 3.47 V and 1 output rated 350 mA, in a 10-VFDFN exposed pad package.
The PM6644TR from STMicroelectronics is a positive adjustable (fixed) 0.9 V (3.47 V) buck switching regulator Integrated Circuit with 1 output rated at 350 mA, in a 10-VFDFN exposed pad package.