Datasheet

DAC7564
SBAS413B –FEBRUARY 2008–REVISED MAY 2011 www.ti.com
LD1 (DB21) and LD0 (DB20) control the loading of DB21 = 0 and DB20 = 1: Single-channel update.
each analog output with the specified 12-bit data The data buffer and DAC register corresponding to a
value or power-down command. Bit DB19 must DAC selected by DB18 and DB17 update with the
always be '0'. The DAC channel select bits (DB18, contents of SR data (or power-down).
DB17) control the destination of the data (or
DB21 = 1 and DB20 = 0: Simultaneous update. A
power-down command) from DAC A through DAC D.
channel selected by DB18 and DB17 updates with
The final control bit, PD0 (DB16), selects the
the SR data; simultaneously, all the other channels
power-down mode of the DAC7564 channels as well
update with previously stored data (or power-down)
as the power-down mode of the internal reference.
from data buffers.
The DAC7564 supports a number of different load DB21 = 1 and DB20 = 1: Broadcast update. All the
commands. The load commands include broadcast DAC7564s on the SPI bus respond, regardless of
commands to address all the DAC7564s on an SPI address matching. If DB18 = 0, SR data are ignored
bus. The load commands are summarized as follows: and any channels from all DAC7564s update with
previously stored data (or power-down). If DB18 = 1,
DB21 = 0 and DB20 = 0: Single-channel store. The
SR data (or power-down) update any channels of all
data buffer corresponding to a DAC selected by
DAC7564s in the system. This broadcast update
DB18 and DB17 updates with the contents of SR
feature allows the simultaneous update of up to 16
data (or power-down).
channels.
Refer to Table 5 for more information.
Table 5. Control Matrix for the DAC7564
DB23 DB22 DB21 DB20 DB19 DB18 DB17 DB16 DB15 DB14 DB13-DB4 DB3-DB0
Don't
A1 A0 LD 1 LD 0 0 DAC Sel 1 DAC Sel 0 PD0 MSB MSB-1 MSB-2...LSB Care
(Address Select) DESCRIPTION
This address selects one of four possible
0/1 0/1 See Below devices on a single SPI data bus based on the
address pin(s) state of each device.
0 0 0 0 0 0 Data X Write to buffer A with data
0 0 0 0 1 0 Data X Write to buffer B with data
0 0 0 1 0 0 Data X Write to buffer C with data
0 0 0 1 1 0 Data X Write to buffer D with data
Write to buffer (selected by DB17 and DB18)
0 0 0 (00, 01, 10, or 11) 1 See Table 6 0 X
with power-down command
A0 and A1 should
Write to buffer with data and load DAC
correspond to the
0 1 0 (00, 01, 10, or 11) 0 Data X
(selected by DB17 and DB18)
package address
set via pins 13
Write to buffer with power-down command and
0 1 0 (00, 01, 10, or 11) 1 See Table 6 0 X
and 14
load DAC (selected by DB17 and DB18)
Write to buffer with data (selected by DB17 and
1 0 0 (00, 01, 10, or 11) 0 Data X DB18) and then load all DACs simultaneously
from their corresponding buffers
Write to buffer with power-down command
(selected by DB17 and DB18) and then load all
1 0 0 (00, 01, 10, or 11) 1 See Table 6 0 X
DACs simultaneously from their corresponding
buffers
Broadcast Modes
Simultaneously update all channels of all
X X 1 1 0 0 X X X X DAC7564 devices in the system with data
stored in each channels data buffer
Write to all devices and load all DACs with SR
X X 1 1 0 1 X 0 Data X
data
Write to all devices and load all DACs with
X X 1 1 0 1 X 1 See Table 6 0 X
power-down command in SR
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