EVAL-AD5666EB AD [Analog Devices], EVAL-AD5666EB Datasheet - Page 21

• Manufacturer Part Number: EVAL-AD5666EB
• Description: Quad, 16-Bit DAC with 5 ppm/C On-Chip Reference in 14-Lead TSSOP
• Manufacturer: AD [Analog Devices]

OUTPUT AMPLIFIER
The output buffer amplifier can generate rail-to-rail voltages on
its output, which gives an output range of 0 V to V
amplifier is capable of driving a load of 2 kΩ in parallel with
1000 pF to GND. The source and sink capabilities of the output
amplifier can be seen in Figure 19 and Figure 20. The slew rate
is 1.5 V/μs with a ¼ to ¾ scale settling time of 10 μs.
SERIAL INTERFACE
The AD5666 has a 3-wire serial interface ( SYNC , SCLK, and
DIN) that is compatible with SPI, QSPI, and MICROWIRE
interface standards as well as most DSPs. See Figure 3 for a
timing diagram of a typical write sequence.
The write sequence begins by bringing the SYNC line low. Data
from the DIN line is clocked into the 32-bit shift register on the
falling edge of SCLK. The serial clock frequency can be as high
as 50 MHz, making the AD5666 compatible with high speed
DSPs. On the 32
in and the programmed function is executed, that is, a change
in DAC register contents and/or a change in the mode of
operation. At this stage, the SYNC line can be kept low or be
brought high. In either case, it must be brought high for a
minimum of 15 ns before the next write sequence so that a
falling edge of SYNC can initiate the next write sequence.
Because the SYNC buffer draws more current when V
than it does when V
between write sequences for even lower power operation of the
part. As is mentioned previously, however, SYNC must be
brought high again just before the next write sequence.
nd
falling clock edge, the last data bit is clocked
IN
= 0.8 V, SYNC should be idled low
DD
. The
IN
= 2 V
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Table 7. Command Definitions
C3
0
0
0
0
0
0
0
0
1
1
–
1
Table 8. Address Commands
A3
0
0
0
0
1
Command
C2
0
0
0
0
1
1
1
1
0
0
–
1
C1
0
0
1
1
0
0
1
1
0
0
–
1
A2
0
0
0
0
1
Address (n)
0
1
0
1
0
1
0
1
0
1
–
1
C0
Description
Write to Input Register n
Update DAC Register n
Write to Input Register n, update all
(software LDAC)
Write to and update DAC Channel n
Power down/power up DAC
Load clear code register
Load LDAC register
Reset (power-on reset)
Set up DCEN/REF register
Reserved
Reserved
Reserved
A1
0
0
1
1
1
A0
0
1
0
1
1
Selected DAC
Channel
DAC A
DAC B
DAC C
DAC D
All DACs
AD5666