
IDT / ICS 2.5V LVPECL FREQUENCY SYNTHESIZER
7
ICS843001AK-40 REV. A OCTOBER 10, 2007
ICS843001-40
FEMTOCLOCKS CRYSTAL-TO-2.5V LVPECL FREQUENCY SYNTHESIZER
PARAMETER MEASUREMENT INFORMATION
LVCMOS OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
LVCMOS CYCLE-TO-CYCLE JITTER
2.5V LVPECL OUTPUT LOAD AC TEST CIRCUIT
SCOPE
Qx
nQx
LVPECL
V
EE
2V
-0.5V ± 0.125V
tcycle n
tcycle n+1
tjit(cc) = tcycle n – tcycle n+1
1000 Cycles
t
PERIOD
t
PW
t
PERIOD
odc =
x 100%
t
PW
REF_OUT
V
CC,
V
CCO_LVPECL
2.5V LVCMOS OUTPUT LOAD AC TEST CIRCUIT
2V
V
CCA
REF_OUT
SCOPE
Qx
LVCMOS
GND
V
CC,
V
CCO_REF_OUT
V
CCA
-1.25V ± 5%
1.25V ± 5%
tcycle n
tcycle n+1
tjit(cc) = tcycle n – tcycle n+1
1000 Cycles
nQ
Q
LVPECL CYCLE-TO-CYCLE JITTER
LVPECL OUTPUT DUTY CYCLE/PULSE WIDTH/PERIOD
t
PW
t
PERIOD
t
PW
t
PERIOD
odc =
x 100%
RMS PHASE JITTER
Phase Noise Mask
Offset Frequency
f
1
f
2
Phase Noise Plot
RMS Jitter = Area Under the Masked Phase Noise Plot
Noise
P
o
w
er
nQ
Q
OUTPUT RISE/FALL TIME
Clock
Outputs
20%
80%
20%
tR
t F
VSWING