Datasheet

AD5724/AD5734/AD5754
Rev. D | Page 24 of 32
INPUT SHIFT REGISTER
The input shift register is 24 bits wide and consists of a read/write bit (R/
W
), a reserved bit (zero) that must always be set to 0, three
register select bits (REG0, REG1, REG2), three DAC address bits (A2, A1, A0), and 16 data bits (data). The register data is clocked in MSB
first on the SDIN pin. shows the register format and describes the function of each bit in the register. All registers are
read/write registers.
Table 16 Table 17
Table 16. Input Register Format
MSB LSB
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 to DB0
R/W
Zero REG2 REG1 REG0 A2 A1 A0 Data
Table 17. Input Register Bit Functions
Bit Mnemonic Description
R/W
Indicates a read from or a write to the addressed register.
REG2, REG1, REG0
Used in association with the address bits to determine if a write operation is to the DAC register, the output range
select register, the power control register, or the control register.
REG2 REG1 REG0 Function
0 0 0 DAC register
0 0 1 Output range select register
0 1 0 Power control register
0 1 1 Control register
A2, A1, A0 These DAC address bits are used to decode the DAC channels.
A2 A1 A0 Channel Address
0 0 0 DAC A
0 0 1 DAC B
0 1 0 DAC C
0 1 1 DAC D
1 0 0 All four DACs
DB15 to DB0 Data bits.
DAC REGISTER
The DAC register is addressed by setting the three REG bits to 000. The DAC address bits select the DAC channel where the data transfer
is to take place (see Table 17). The data bits are in positions DB15 to DB0 for the AD5754 (see Table 1 8 ), DB15 to DB2 for the AD5734
(see Table 19), and DB15 to DB4 for the AD5724 (see Table 20).
Table 18. Programming the AD5754 DAC Register
MSB LSB
R/
W
Zero REG2 REG1 REG0 A2 A1 A0 DB15 to DB0
0 0 0 0 0 DAC address 16-bit DAC data
Table 19. Programming the AD5734 DAC Register
MSB LSB
R/
W
Zero REG2 REG1 REG0 A2 A1 A0 DB15 to DB2 DB1 DB0
0 0 0 0 0 DAC address 14-bit DAC data X X
Table 20. Programming the AD5724 DAC Register
MSB LSB
R/
W
Zero REG2 REG1 REG0 A2 A1 A0 DB15 to DB4 DB3 DB2 DB1 DB0
0 0 0 0 0 DAC address 12-bit DAC data X X X X