Datasheet
MAX548A/MAX549A/MAX550A
+2.5V to +5.5V, Low-Power, Single/Dual,
8-Bit Voltage-Output DACs in µMAX Package
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Table 4. MAX550A Serial-Interface Programming Commands
COMMANDS LOADING DAC REGISTER
COMMANDS LOADING INPUT REGISTER ONLY
UNASSIGNED COMMANDS
Loaded LastLoaded First
LDAC
CONTROL BYTE
COMMAND
(Commands executed on CS’s rising edge)
X
Update DAC register with current contents of
input register. Input register unchanged.
00X11X 0X XXXXXXXX
X Load DAC input register and update DAC register.08-Bit DAC Data1X11X 0X
XXXXXXXX
X Load DAC input register and update DAC register.X8-Bit DAC Data1X01X 0X
UB1 Pin 6D7........D0A0A1C0C1UB3 C2UB2
X
Update DAC register with current contents of
input register. Input register unchanged.
X0X01X 0X
X Load DAC input register. DAC register unchanged.X8-Bit DAC Data1XX0X 0X
X Unassigned operationXXXXXXXXX0XX
X
XX 1X
Unassigned commandXXXXXXXXX0XX0X 0X
DATA BYTE
COMMANDS UTILIZING THE ASYNCHRONOUS LOAD FUNCTION
X
After CS’s rising edge and on LDAC’s falling
edge, update DAC register with current contents
of input register. Input register unchanged.
1XXXXXXXX0X11X 0X
X
Load DAC input register. After CS’s rising edge
and on LDAC’s falling edge, update DAC register.
18-Bit DAC Data1X11X 0X
COMMAND POWERING DOWN AND LOADING INPUT REGISTER ONLY
X Load DAC input register and power down DAC.X8-Bit DAC Data1XX0X 1X
COMMANDS POWERING DOWN AND UPDATING DAC REGISTER
X
Load DAC input register, power down DAC, and
update DAC register.
X8-Bit DAC Data1X01X 1X
X
Load DAC input register, power down DAC, and
update DAC register.
08-Bit DAC Data1X11X 1X
COMMAND POWERING DOWN AND UTILIZING THE ASYNCHRONOUS LOAD FUNCTION
X
Load DAC input register and power down DAC.
While powered down, on LDAC’s falling edge,
update DAC register.
18-Bit DAC Data1X11X 1X
Table 5. Example Input Word
X = Don’t care
X = Don’t care
UB2
X
C2
0
UB3
X
C0
0
CONTROL BYTE
A0
1
Loaded First
A1
0
C1
1
D6
0
D4
0
D5
0
D2
0
DATA BYTE
D0
0
Loaded Last
D1
0
D3
0
D7
1
UB1
X