CDC2536

3.3-V PHASE-LOCK LOOP CLOCK DRIVER

WITH 3-STATE OUTPUTS

SCAS377D – APRIL 1994 – REVISED OCTOBER 1998

6

POST OFFICE BOX 655303

timing requirements over recommended ranges of supply voltage and operating free-air

temperature

MIN

MAX

UNIT

f lk

Clock frequency

When VCO is operating at four times the CLKIN frequency

25

50

MHz

fclock

Clock frequency

When VCO is operating at double the CLKIN frequency

50

100

MHz

Duty cycle, CLKIN

40%

60%

†

After SEL

50

Stabilization time†

After OE

↓

50

µs

Stabilization time†

After power up

50

µs

After CLKIN

50

† 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 CLKIN. Until phase lock is obtained, the specifications for propagation delay

and skew parameters given in the switching characteristics table are not applicable.

switching characteristics over recommended ranges of supply voltage and operating free-air

PARAMETER

FROM

(INPUT)

TO

(OUTPUT)

MIN

MAX

UNIT

fmax

100

MHz

Duty cycle

Y

45%

55%

tphase error‡

CLKIN

↑

Y

↑

–500

+500

ps

tjitter (RMS)

CLKIN

↑

Y

↑

200

ps

tsk(o)‡

0.5

ns

tsk(pr)‡

1

ns

tr

1.4

ns

tf

1.4

ns

‡ The propagation delay, tphase error, is dependent on the feedback path from any output to FBIN. The tphase error, tsk(o), and tsk(pr)specfications

are only valid for equal loading of all outputs.

NOTE 4: The specifications for parameters in this table are applicable only after any appropriate stabilization time has elapsed.

PARAMETER MEASUREMENT INFORMATION

From Output

Under Test

LOAD CIRCUIT FOR OUTPUTS

CL = 15pF

(see Note A)

VOLTAGE WAVEFORMS

PROPAGATION DELAY TIMES

tphase error

1.5 V

1.5 V

3 V

0 V

1.5 V

VOH

VOL

Input

0.8 V

2 V

tr

tf

0.8 V

2 V

Output

500

W

NOTES: A. CL includes probe and jig capacitance.

B. All input pulses are supplied by generators having the following characteristics: PRR

≤ 100 MHz, ZO = 50 Ω, tr ≤ 2.5 ns, tf ≤ 2.5 ns.

C. The outputs are measured one at a time with one transition per measurement.

Figure 1. Load Circuit and Voltage Waveforms