DAC5686 Datasheet, PDF (32/46 Pages) Texas Instruments – 16-BIT, 500-MSPS, 2X16X INTERPOLATING DUAL-CHANNEL DIGITAL-TO-ANALOG CONVERTER

DAC5686
SLWS147B – APRIL 2003 – REVISED AUGUST 2004
Table 4. Filter Taps for FIR1–FIR5 (continued)
FIR1
20750
32768
20750
0
–6628
0
3649
0
–2288
0
1490
0
–971
0
619
0
–380
0
221
0
–120
0
58
0
–24
0
8
FIR2
FIR3
FIR4
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FIR5 (INVSINC)
NCO
The DAC5686 uses a numerically controlled oscillator (NCO) with a 32-bit frequency register and a 16-bit phase
register. The NCO is used in quadrature-modulation and single-sideband modes to provide sin and cos for
mixing. The NCO tuning frequency is programmed in registers 0x1 through 0x4. Phase offset is programmed is
registers 0x5 and 0x6. A block diagram of the NCO is shown in Figure 41.
32
32
Frequency
Register
32 Accumulator 32 16
16
Σ
Σ
Look-Up
Table
CLK RESET
F_DAC
PHSTR
16
Phase
Register
16
sin
16
cos
Figure 41. Block Diagram of the NCO
32