check the wiki and this table

17 = 0x11 = 0.812V x 0 MHz = 0
17 = 0x11 = 0.812V x 125 MHz = 83
20 = 0x14 = 0.850V x 250 MHz = 181
30 = 0x1e = 0.975V x 500 MHz = 475
33 = 0x21 = 1.012V x 550 MHz = 564
35 = 0x23 = 1.038V x 600 MHz = 646
40 = 0x28 = 1.100V x 700 MHz = 847
43 = 0x2b = 1.137V x 750 MHz = 970
45 = 0x2d = 1.163V x 810 MHz = 1095
47 = 0x2f = 1.188V x 850 MHz = 1199
50 = 0x32 = 1.225V x 900 MHz = 1351
53 = 0x35 = 1.263V x 950 MHz = 1514
58 = 0x3a = 1.325V x 1000 MHz = 1756
64 = 0x40 = 1.400V x 1100 MHz = 2156
70 = 0x46 = 1.475V x 1150 MHz = 2502