Datasheet

MAX520/MAX521
Quad/Octal, 2-Wire Serial 8-Bit DACs
with Rail-to-Rail Outputs
12 ______________________________________________________________________________________
( )
( )
SDA
SDA
0
START
CONDITION
ADDRESS BYTE ACK
ACK
1 0 1 AD1 AD0 0 0000000000
11 111111 0010000000000000001
0000000
00
1
111
11
11
1
STOP
CONDITION
OUTPUT BYTE
(FULL SCALE)
COMMAND BYTE
(ADDRESSING DAC0)
ACK
OUTPUT BYTE
(FULL SCALE)
ACK
COMMAND BYTE
(ADDRESSING DAC2)
ACK
OUTPUT BYTE
(HALF SCALE)
ACK
COMMAND BYTE
(ADDRESSING DAC1)
ACK
DAC OUTPUTS CHANGE HERE: 
DACS 0 AND 1 GO TO FULL SCALE,
DAC 2 GOES TO HALF SCALE.
DAC0 INPUT LATCH
SET TO FULL SCALE
( )
( )
DAC2 INPUT LATCH
SET TO HALF SCALE
DAC1 INPUT LATCH
SET TO FULL SCALE
0 OR AD2
Figure 7. Setting DAC Outputs
SDA
0
START
CONDITION
ADDRESS BYTE ACK
1 0 1 AD1 AD0 0 0 000001
(PD)
(PD)
STOP
CONDITION
COMMAND BYTE
ACK
DEVICE ENTERS
POWER-DOWN STATE
( )
SDA
0
START
CONDITION
ADDRESS BYTE ACK
1 0 1 AD1 AD0 0 0 0
0
00001000
1111
1
11
1
STOP
CONDITION
COMMAND BYTE
(ADDRESSING DAC0)
ACK
OUTPUT BYTE
(FULL SCALE)
ACK
(a)
(b)
DEVICE ENTERS POWER-DOWN STATE.
DAC 0 OUTPUT LATCH SET TO FULL SCALE.
NOTE: X = DON'T CARE
DAC 0 INPUT LATCH
SET TO FULL SCALE
X X X
( )
( )
0 OR AD2
0 OR AD2
Figure 8. Entering the Power-Down State
( )
SDA
0
START
CONDITION
ADDRESS BYTE ACK
1 0 1 AD1 AD0 0 0 000000
(PD)
(PD)
STOP
CONDITION
COMMAND BYTE
ACK
DEVICE RETURNS TO 
NORMAL OPERATION
( )
DAC3 OUTPUT
LATCH SET TO 0
SDA
0
START
CONDITION
ADDRESS BYTE ACK
1 0 1 AD1 AD0 0 00 0000011
0
00
0
00
00
00
STOP
CONDITION
COMMAND BYTE
(ADDRESSING DAC3)
ACK
OUTPUT BYTE
(SET TO 0)
ACK
(a)
(b)
DEVICE RETURNS TO NORMAL OPERATION.
DAC 3 SET TO 0.
NOTE: X = DON'T CARE
X X X
( )
0 OR AD2
0 OR AD2
Figure 9. Returning to Normal Operation from Power-Down