Datasheet

AD5764 Data Sheet
Rev. F | Page 22 of 28
FINE GAIN REGISTER
The fine gain register is addressed by setting the three REG bits
to 100. The DAC address bits select with which DAC channel
the data transfer is to take place (see Table 10). The fine gain
register is a 6-bit register and allows the user to adjust the gain
of each DAC channel by −32 LSBs to +31 LSBs in 1 LSB
increments, as shown in Table 16 and Table 1 7 . The adjustment
is made to both the positive full-scale points and the negative
full-scale points simultaneously, each point being adjusted by ½
of one step. The fine gain register coding is twos complement.
OFFSET REGISTER
The offset register is addressed by setting the three REG bits to
101. The DAC address bits select with which DAC channel the
data transfer is to take place (see Table 10). The AD5764 offset
register is an 8-bit register and allows the user to adjust the offset
of each channel by −16 LSBs to +15.875 LSBs in increments of
⅛ LSB, as shown in Table 18 and Table 19. The offset register
coding is twos complement.
Table 16. Programming the Fine Gain Register Bit Map
REG2 REG1 REG0 A2 A1 A0 DB15:DB6 DB5 DB4 DB3 DB2 DB1 DB0
1 0 0 DAC address Don’t care FG5 FG4 FG3 FG2 FG1 FG0
Table 17. Fine Gain Register Options
Gain Adjustment FG5 FG4 FG3 FG2 FG1 FG0
+31 LSBs 0 1 1 1 1 1
+30 LSBs 0 1 1 1 1 0
… … … … … … …
+2 LSBs 0 0 0 0 1 0
+1 LSB 0 0 0 0 0 1
No Adjustment (Default) 0 0 0 0 0 0
−1 LSB 1 1 1 1 1 1
−2 LSBs 1 1 1 1 1 0
… … … … … … …
−31 LSBs 1 0 0 0 0 1
−32 LSBs 1 0 0 0 0 0
Table 18. Programming the Offset Register Bit Map
REG2 REG1 REG0 A2 A1 A0 DB15:DB8 DB7 DB6 DB5 DB4 DB3 DB2 DB1 DB0
1 0 1 DAC address Don’t care OF7 OF6 OF5 OF4 OF3 OF2 OF1 OF0
Table 19. AD5764 Offset Register Options
Offset Adjustment OF7 OF6 OF5 OF4 OF3 OF2 OF1 OF0
+15.875 LSBs 0 1 1 1 1 1 1 1
+15.75 LSBs 0 1 1 1 1 1 1 0
… … … … … … … … …
+0.25 LSBs 0 0 0 0 0 0 1 0
+0.125 LSBs 0 0 0 0 0 0 0 1
No Adjustment (Default) 0 0 0 0 0 0 0 0
−0.125 LSBs 1 1 1 1 1 1 1 1
−0.25 LSBs 1 1 1 1 1 1 1 0
… … … … … … … … …
−15.875 LSBs 1 0 0 0 0 0 0 1
−16 LSBs 1 0 0 0 0 0 0 0