Datasheet

DAC7564

www.ti.com

SBAS413B –FEBRUARY 2008–REVISED MAY 2011

Example 5: Power-Down All Channels Simultaneously while Reference is Always Powered Up

• 1st: Write sequence for enabling the DAC7564 internal reference all the time:

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11-DB4 DB3-DB0

(A1) (A0) (LD1) (LD0) (DAC Sel 1) (DAC Sel 0) (PD0)

0 0 0 0 0 0 0 1 0 0 0 1 X X

• 2nd: Write sequence to power-down all DACs to high-impedance:

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11-DB4 DB3-DB0

(A1) (A0) (LD1) (LD0) (DAC Sel 1) (DAC Sel 0) (PD0)

0 0 1 1 0 1 0 1 1 1 X X X X

The DAC A, DAC B, DAC C, and DAC D analog outputs sequentially power-down to high-impedance upon

completion of the first and second write sequences, respectively.

Example 6: Write a Specific Value to All DACs while Reference is Always Powered Down

• 1st: Write sequence for disabling the DAC7564 internal reference all the time (after this sequence, the

DAC7564 requires an external reference source to function):

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11-DB4 DB3-DB0

(A1) (A0) (LD1) (LD0) (DAC Sel 1) (DAC Sel 0) (PD0)

0 0 0 0 0 0 0 1 0 0 1 0 X X

• 2nd: Write sequence to write specified data to all DACs:

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11-DB4 DB3-DB0

(A1) (A0) (LD1) (LD0) (DAC Sel 1) (DAC Sel 0) (PD0)

0 0 1 1 0 1 0 0 D11 D10 D9 D8 D7–D0 X

The DAC A, DAC B, DAC C, and DAC D analog outputs simultaneously settle to the specified values upon

completion of the fourth write sequence. (The DAC voltages update simultaneously after the 24th SCLK falling

edge of the fourth write cycle). Reference is always powered-down.

Example 7: Write a Specific Value to DAC A, while Reference is Placed in Default Mode and All Other

DACs are Powered Down to High-Impedance

• 1st: Write sequence for placing the DAC7564 internal reference into default mode. Alternately, this step can

be replaced by performing a power-on reset (see the Power-On Reset section):

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11-DB4 DB3-DB0

(A1) (A0) (LD1) (LD0) (DAC Sel 1) (DAC Sel 0) (PD0)

0 0 0 0 0 0 0 1 0 0 0 0 X X

• 2nd: Write sequence to power-down all DACs to high-impedance (after this sequence, the DAC7564 internal

reference powers down automatically):

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11-DB4 DB3-DB0

(A1) (A0) (LD1) (LD0) (DAC Sel 1) (DAC Sel 0) (PD0)

0 0 1 1 0 1 0 1 1 1 X X X X

• 3rd: Write sequence to power-up DAC A to a specified value (after this sequence, the DAC7564 internal

reference powers up automatically):

DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13 DB12 DB11-DB4 DB3-DB0

(A1) (A0) (LD1) (LD0) (DAC Sel 1) (DAC Sel 0) (PD0)

0 0 0 1 0 0 0 0 D11 D10 D9 D8 D7–D0 X

The DAC B, DAC C, and DAC D analog outputs simultaneously power-down to high-impedance, and DAC A

settles to the specified value upon completion.