CDC857 Datasheet, PDF (6/12 Pages) Texas Instruments – 2.5-/3.3-V PHASE-LOCK LOOP CLOCK DRIVERS

CDC857-2, CDC857-3
2.5-/3.3-V PHASE-LOCK LOOP CLOCK DRIVERS
SCAS627A – SEPTEMBER 1999 – DECEMBER 1999
timing requirements over recommended ranges or supply voltage and operating free–air
temperature
PARAMETER
TEST CONDITIONS
MIN
MAX UNIT
fC
Clock frequency
66
167 MHz
Input clock duty cycle
40%
60%
Stabilization time†
0.1 ms
† _{Time required for the integrated PLL circuit to obtain phase lock of its feedback signal to its reference signal. For phase lock to be obtained, a}
fixed–frequency, fixed–phase reference signal must be present at CLK. Until phase lock is obtained, the specifications for propagation delay,
skew, and jitter parameters given in the switching characteristics table are not applicable. This parameter does not apply for input modulation
under SSC application.
switching characteristics
PARAMETER
TEST CONDITIONS
MIN NOM MAX UNIT
tPLH‡
Low–to high level propagation delay time
(see Figure 5)
CLK mode/CLK to any output
1.5 3.5
6 ns
tPHL‡
High–to low level propagation delay time
(see Figure 5)
CLK mode/CLK to any output
1.5 3.5
6 ns
ten
tdis
t(jitter)
Output enable time
Output disable time
Jitter (peak-to–peak)
CLK mode/G to any Y output
CLK mode/G to any Y output
66 MHz
100/125/133/167 MHz
3
ns
3
ns
120
ps
75
t(jitter)
Jitter (cycle-to-cycle)
66 MHz
100/125/133/167 MHz
110
ps
65
t(phase _error)
tskew(0)
tskew(p)
Phase error (see Figure 4)
Output skew (see Figure 4)
Pulse skew
Duty cycle§ (see Figure 6)
All differential input and output termi-
nals are terminated with 120 Ω/
16 pF as shown in Figure 2
–150
66 MHz to 100 MHz
101 MHz to 167 MHz
49.5%
49%
150 ps
100 ps
100 ps
50.5%
51%
tr, tf
Output rise and fall times (20% – 80%)
Load = 120 Ω/16 pF
650 800
950 ps
‡ _{Refers to transition of noninverting output.}
§ _{While the pulse skew is almost constant over frequency, the duty cycle error increases at higher frequencies. This is due to the formula: duty}
cycle = twH/tc, were the cycle time (tc) decreases as the frequency goes up.
6
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