AD9778 Analog Devices, AD9778 Datasheet - Page 45

• Manufacturer Part Number: AD9778
• Description: Dual 14-Bit, 1 GSPS, Digital-to-Analog Converter
• Manufacturer: Analog Devices

Specifications of AD9778

• Resolution (bits): 14bit
• Dac Update Rate: 1GSPS
• Dac Settling Time: n/a
• Max Pos Supply (v): +3.47V
• Single-supply: No
• Dac Type: Current Out
• Dac Input Format: Par

In addition to this divisor function, DATACLK can be divided
by up to an additional factor of 4, according to the state of the
DATACLK divide register (Register 0x03, Bits<5:4>). For more
details, see Table 22).
Table 22. Extra DATACLK Divisor Ratio
Register 0x03, Bits<5:4>
00
01
10
11
The maximum divisor resulting from the combination of the
values in Table 21, and the DATACLK divide register is 32.
Manual Input Timing Correction
Correction of input timing can be achieved manually. The
correction function is controlled by Register 0x03, Bits<7:6>.
The function is programmed as shown in Table 23.
Table 23. Input Timing Correction Mode
Register 0x03, Bits<7:6>
00
01
10
11
Divider Ratio
1
2
4
1
Function
Error check disabled
Reserved
Reserved
Reserved
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Necessary corrections can be made by adjusting DATACLK
delay and the DATACLK invert bit (Register 2, Bit 2).
DATACLK delay can then be swept to find the range over which
the timing is valid. The final value for data delay should be the
value that corresponds to the middle of the valid timing range.
If a valid timing range is not found during this sweep, the user
should invert the DATACLK invert bit and repeat the process.
Multiple DAC Synchronization
The AD9779 has programmable features that allow the CMOS
digital data bus inputs and internal filters on multiple devices to
be synchronized. This means that the DATACLK output signal
on one AD9779 can be used to register the output data for a data
bus delivering data to multiple AD9779s. The details of this opera-
tion are given in the Analog Devices Application Note AN-822.
AD9776/AD9778/AD9779