Software Control
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●
NCO: allows fine mixing of the I/Q signal. The procedure to adjust the NCO mixing frequency are
listed below:
1. Enter the DAC sampling frequency in Fsample.
2. Enter the desired mixing frequency in both NCO freq_AB and NCO freq_CD.
3. Press Update freq
4. Sync the NCO block from the following options:
●
REGWR: auto-sync from SIF register write. Writing to either Phase OffsetAB or Phase
OffsetCD can create a sync event.
●
OSTR: sync from the external LVPECL OSTR signal. Clock divider sync must be enabled
with OSTR set as sync source. Refer to the datasheet for OSTR period requirement.
●
SYNC: sync from the external SYNC signal
●
SIF SYNC: sync from SIF Sync. Uncheck and check the SIF Sync button for sync
event.
2.2.3
Output Control Options
Figure 5. Output Control Options
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Output Options: allows the configuration of reference, output polarity, and output delay
●
Data Routing: provides flexible routing of the A, B, C, and D digital path to the desired output
channels.
Note: The DAC3482 does not support this mode.
●
DAC Gain: configures the full-scale DAC current and DAC3484/DAC3482 mode. With Rbiaj resistor
set at 1.28k
Ω
:
O DAC Gain = 15 for 30mA full-scale current.
O DAC Gain = 10 for 20mA full-scale current (default).
O DAC3484 = QDAC
O DAC3482 = DDAC
●
This allows the DAC3484 to be configured as DAC3482 (see Using DAC3484 as DAC3482
section for detail)
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DAC Sel = Enable inner outputs of Ch. B and Ch. C as the DAC3482 output.
●
DAC Sel = Enable outer outputs of Ch. A and Ch. D as the DAC3482 output. Outer
channels are grounded for the DAC3482 device.
●
Output Shutoff On: allows outputs to shut-off when DACCLK GONE, DATACLK GONE, or FIFO
COLLISION alarm event occurs.
6
DAC3484/DAC3482 EVM
SLAU336 – March 2011
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