AS1504, AS1505
austriam
i c r o
systems
Data Sheet
8 Detailed Description
The AS1504/AS1505 contain eight DAC channels of programmable voltage output adjustment capability. OUT
x
can be
individually changed in random sequence. The fast serial-data loading (33MHz) allows all eight DACs to be quickly
loaded (3ms typ; 12 x 8 x 30ns).
Figure 11. Detailed Block Diagram
CSN
D7
D6
D5
D4 DAC1
D3 Register
D2
D1
D0
R
V
REFH
CLK
D10
D9
D8
GND
D7
D6
D5
D4
D3
D2
D1
D0
Serial
Register
EN
Address
Decode
DAC1
OUT1
8
D
SDI
8
D7
D6
D5
D4 DAC8
D3 Register
D2
D1
D0
R
DAC1
OUT8
8
SHDNN
RSN
AS1504 Only
AS1504/
AS1505
V
REFL
AS1505 Only
Each output voltage can be programmed by clocking an 11-bit serial data word into pin SDI
The format
of this data word is three address bits (MSB first, followed by eight data bits
To determine which of the DAC registers is to receive the serial register data (bits B7:B0) the DACx address is
decoded as:
DACx = A2 x 4 + A1 x 2 + A0 + 1
Figure 12. Timing Diagram
SDI
1
A2
0
A1
A0
D7
D6
D5
D4
D3
D2
D1
DO
(EQ 1)
CLK
1
0
1
0
DAC Register Load
CSN
V
OUT
+5V
0V
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