Datasheet

AD9517-1 Data Sheet
Rev. E | Page 48 of 80
1234567
8
910
INPUT TO VCO DIVIDER
INPUT TO CHANNEL DIVIDER
OUTPUT OF
CHANNEL DIVIDER
S
YNC PIN
1
11
12
13 14
14 TO 15 CYCLES AT CHANNEL DIVIDER INPUT + 1 CYCLE AT VCO DIVIDER INPUT
CHANNEL DIVIDER OUTPUT STATIC
CHANNEL DIVIDE
R
OUTPUT CLOCKING
CHANNEL DIVIDE
R
OUTPUT CLOCKING
06425-073
Figure 57. SYNC Timing When VCO Divider Is Used—CLK or VCO Is Input
INPUT TO CLK
IINPUT TO CHANNEL DIVIDER
OUTPUT OF
CHANNEL DIVIDER
SYNC PIN
14 TO 15 CYCLES AT CHANNEL DIVIDER INPUT + 1 CYCLE AT CLK INPUT
1234567
8
910
11
12
13 14
1
CHANNEL DIVIDER OUTPUT STATIC
CHANNEL DIVIDE
R
OUTPUT CLOCKING
CHANNEL DIVIDER
OUTPUT CLOCKING
0
6425-074
Figure 58. SYNC Timing When VCO Divider Is Not Used—CLK Input Only
A sync operation brings all outputs that have not been excluded
(by the nosync bit) to a preset condition before allowing the
outputs to begin clocking in synchronicity. The preset condition
takes into account the settings in each of the channel’s start high
bit and its phase offset. These settings govern both the static
state of each output when the sync operation is happening and
the state and relative phase of the outputs when they begin clocking
again upon completion of the sync operation. Between outputs
and after synchronization, this allows for the setting of phase
offsets.
The AD9517 outputs are in pairs, sharing a channel divider per
pair (two pairs of pairs, four outputs, in the case of CMOS). The
synchronization conditions apply to both outputs of a pair.
Each channel (a divider and its outputs) can be excluded from
any sync operation by setting the nosync bit of the channel.
Channels that are set to ignore SYNC (excluded channels) do
not set their outputs static during a sync operation, and their
outputs are not synchronized with those of the nonexcluded
channels.
Clock Outputs
The AD9517 offers three different output level choices:
LVPECL, LVDS, and CMOS. OUT0 to OUT3 are LVPECL
differential outputs; and OUT4 to OUT7 are LVDS/CMOS
outputs. These outputs can be configured as either LVDS
differential or as pairs of single-ended CMOS outputs.