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AS1504, AS1505

Data Sheet

8 Detailed Description

The AS1504/AS1505 contain eight DAC channels of programmable voltage output adjustment capability. OUTx 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

Each output voltage can be programmed by clocking an 11-bit serial data word into pin SDI (see Figure 12). The format

of this data word is three address bits (MSB first, followed by eight data bits (see Table 5)).

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

(EQ 1)

Figure 12. Timing Diagram

OUT1

OUT8

AS1504 Only

RSN

AS1505 Only

SDI

CLK

CSN

AS1504/

AS1505

SHDNN

Address

Decode

EN

Serial

Register

D10

D9

D8

D

8

GND

DAC1

Register

D7

D6

D5

D4

D3

D2

D0

D1

D7

D6

D5

D4

D3

D2

D1

D0

DAC8

Register

D7

D6

D5

D4

D3

D2

D1

D0

R

R

DAC1

DAC1

8

8

SDI

CLK

CSN

1

0

1

0

1

0

+5V

0V

DAC Register Load

A2

A0

D7

D6

D5

D4

D3

D2

D1

DO

A1