Texas Instruments DAC3482 用户手册
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:
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:
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REGWR: auto-sync from SIF register write. Writing to either Phase OffsetAB or Phase
OffsetCD can create a sync event.
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.
with OSTR set as sync source. Refer to the datasheet for OSTR period requirement.
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SYNC: sync from the external SYNC signal
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SIF SYNC: sync from SIF Sync. Uncheck and check the SIF Sync button for sync
event.
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
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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.
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
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)
section for detail)
●
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.
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.
COLLISION alarm event occurs.
6
DAC3484/DAC3482 EVM
SLAU336 – March 2011
© 2011, Texas Instruments Incorporated