Datasheet

DAC3484
SLAS749C –MARCH 2011–REVISED AUGUST 2012 www.ti.com
freq = f
NCO
x 2^32 / 1228.8 = 429496730 = 0x1999999A
phaseaddAB(31:0) or phaseaddCD(31:0) = 0x19999999A
NCO SYNC = sif_sync
EXAMPLE START-UP SEQUENCE
Table 10. Example Start-Up Sequence Description
STEP READ/WRITE ADDRESS VALUE DESCRIPTION
1 N/A N/A N/A Set TXENABLE Low
2 N/A N/A N/A Power-up the device
3 N/A N/A N/A Apply LVPECL DACCLKP/N for PLL reference clock
4 N/A N/A N/A Toggle RESETB pin
QMC offset and correction enabled, 4x int, FIFO enabled, Alarm enabled,
5 Write 0x00 0xF29F
clock divider sync enabled, inverse sinc filter enabled.
6 Write 0x01 0x050E Single parity enabled, FIFO alarms enabled (2 away, 1 away, and collision).
Output shut-off when DACCLK gone, DATACLK gone, and FIFO collision.
7 Write 0x02 0xF052
Mixer block with NCO enabled, twos complement. Word Wide Interface.
Output current set to 20mAFS with internal reference and 1.28kohm R
BIAS
8 Write 0x03 0xA000
resistor.
Un-mask FIFO collision, DACCLK-gone, and DATACLK-gone alarms to the
9 Write 0x07 0xD8FF
Alarm output.
Program the desired channel A QMC offset value. (Causes Auto-Sync for
10 Write 0x08 N/A
QMC AB-Channels Offset Block)
11 Write 0x09 N/A Program the desired FIFO offset value and channel B QMC offset value.
Program the desired channel C QMC offset value. (Causes Auto-Sync for
12 Write 0x0A N/A
QMC CD-Channels Offset Block)
13 Write 0x0B N/A Program the desired channel D QMC offset value.
14 Write 0x0C N/A Program the desired channel A QMC gain value.
Coarse mixer mode not used. Program the desired channel B QMC gain
15 Write 0x0D N/A
value.
16 Write 0x0E N/A Program the desired channel C QMC gain value.
17 Write 0x0F N/A Program the desired channel D QMC gain value.
Program the desired channel AB QMC phase value. (Causes Auto-Sync
18 Write 0x10 N/A
QMC AB-Channels Correction Block)
Program the desired channel CD QMC phase value. (Causes Auto-Sync for
19 Write 0x11 N/A
the QMC CD-Channels Correction Block)
Program the desired channel AB NCO phase offset value. (Causes Auto-
20 Write 0x12 N/A
Sync for Channel AB NCO Mixer)
Program the desired channel CD NCO phase offset value. (Causes Auto-
21 Write 0x13 N/A
Sync for Channel CD NCO Mixer)
22 Write 0x14 0x999A Program the desired channel AB NCO frequency value
23 Write 0x15 0x1999 Program the desired channel AB NCO frequency value
24 Write 0x16 0x999A Program the desired channel CD NCO frequency value
25 Write 0x17 0x1999 Program the desired channel CD NCO frequency value
PLL enabled, PLL N-dividers sync enabled, single charge pump, prescaler =
26 Write 0x18 0x2C58
3.
27 Write 0x19 0x20F4 M = 32, N = 16, PLL VCO bias tune = “01”
28 Write 0x1A 0x9000 PLL VCO coarse tune = 36
29 Write 0x1B 0x0800 Internal reference
QMC offset AB, QMC offset CD, QMC correction AB, and QMC correction
30 Write 0x1E 0x9999
CD can be synced by sif_sync or auto-sync from register write
Mixer AB and CD values synced by SYNCP/N. NCO accumulator synced by
31 Write 0x1F 0x4440
SYNCP/N.
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