Datasheet

AD5666
Rev. D | Page 24 of 28
Table 9. Daisy-Chain Enable/Internal Reference Register
DCEN (DB1) REF (DB0) Action
0 0 Standalone mode, reference off (default)
0 1 Standalone mode, reference on
1 0
DCEN mode, reference off
1 1 DCEN mode, reference on
Table 10. 32-Bit Input Shift Register Contents for Daisy-Chain Enable and Reference Set-Up Function
MSB LSB
DB31 to DB28 DB27 DB26 DB25 DB24 DB23 DB22 DB21 DB20 DB19 to DB2 DB1 DB0
X 1 0 0 0 X X X X X 1/0 1/0
Don’t cares Command bits (C3 to C0) Address bits (A3 to A0) Don’t cares
DCEN/REF
register
Table 11. Modes of Operation
DB9 DB8 Operating Mode
0 0 Normal operation
Power-down modes
0 1
1 kΩ to GND
1 0
100 kΩ to GND
1 1 Three-state
Table 12. 32-Bit Input Shift Register Contents for Power-Up/Power-Down Function
MSB LSB
DB31 to
DB28 DB27 DB26 DB25 DB24 DB23 DB22 DB21 DB20
DB19 to
DB10 DB9 DB8
DB7 to
DB4 DB3 DB2 DB1 DB0
X 0 1 0 0 X X X X X PD1 PD0 X DAC D DAC C DAC B DAC A
Don’t
cares
Command bits (C2 to C0) Address bits (A3 to A0)—
don’t cares
Don’t
cares
Power-down
mode
Don’t
cares
Power-down/power-up channel selection—
set bit to 1 to select
RESISTOR
NETWORK
V
OUT
RESISTOR
STRING DAC
05298-027
POWER-DOWN
CIRCUITRY
AMPLIFIER
Figure 44. Output Stage During Power-Down