DAC5687IPZP datasheet(50/79 Pages) TI

50 / 79 page

www.ti.com

T0155-01

PHSTR

clk_in

clk_out

phstratFIFO

Output

clk_cmix

Sequencer

fs/2

OnlyMustBeHighforOneclk_inPeriod

InputDelayLine+FIFODelay

180

270

Sequencer

fs/4

Sequencer

Reset

Input Clock Synchronization of Multiple DAC5687s

DAC5687

SLWS164E – FEBRUARY 2005 – REVISED SEPTEMBER 2006

Figure 57. CMIX Reset Synchronization Timing

In addition to the reset function provided by the PHSTR signal, the phstr_del(1:0) bits in register ATEST allow

the user to select the initial (reset) state. Changing the cm_mode lower 2 bits produces the same phase shift

results.

Table 14. Initial State of CMIX After Reset

Fix Mix Selection

phstr_del(1:0)

Initial State at PHSTR

fS/2

00 and 10

Normal

fS/2

01 and 11

180-degree shift

fS/4

Normal

fS/4

90-degree shift

fS/4

180-degree shift

fS/4

270-degree shift

For applications where multiple DAC5687 chips are used, clock synchronization is best achieved by using

dual-clock mode with the FIFO disabled or the PLL-clock mode. In the dual-clock mode with FIFO disabled, an

appropriate clock PLL such as the CDC7005 is required to provide the DAC and input rate clocks that meet the

skew requirement talign (see Figure 47). An example for synchronizing multiple DAC5687 devices in dual clock

mode with two CDC7005s is shown in Figure 58. When using the internal PLL-clock mode, synchronization of

multiple using PHSTR is completely deterministic due to the phase/frequency detector in the PLL feedback loop.

All chips using the same CLK1/CLK1C input clock have identical internal clocking phases.

Submit Documentation Feedback

Product Folder Link(s): DAC5687

DAC5687IPZP датащи(PDF) 50 Page - Texas Instruments

DAC5687IPZP датащи(HTML) 50 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79

датащи скачать

ссылки URL