669.327 MHz

Optical Timing Clock

RF Monolithics, Inc.

Phone: (972) 233-2903

Fax: (972) 387-8148

E-mail: info@rfm.com

Page 2 of 5

RFM Europe

Phone: 44 1963 251383

Fax: 44 1963 251510

http://www.rfm.com

©1999 by RF Monolithics, Inc. The stylized RFM logo are registered trademarks of RF Monolithics, Inc.

OP4008B-041003

OP4008B Tuning

The OP4008B will tune from 0 to 5 volts as shown in

the adjacent plot. For normal use in a PLL, the tuning

voltage will not change much from the nominal oper-

ating point. The operating point is determined by: (1)

the temperature of the OP4008B case, (2) the refer-

ence frequency from the PLL, and (3) the internal

characteristics of the key components used in the

OP4008B part. Although the nominal operating point

may be different from part to part by up to 1 volt, the

locked operation of the part in a PLL will not tune

more than 0.5 volts, allowing good linearity over the

operating range.

OP4008B

669

669.1

669.2

669.3

669.4

669.5

669.6

669.7

669.8

0

4

6

MHz

Tune Volts

2

REF

holdover

Xtal

Loop Filter

Tune

+Vcc

Q

Q

N

.

.

Typical PLL

OP4008B

RFM's OPB-series Voltage Controlled SAW Clocks are designed for use in Phase Lock Loops (PLL’s) for optical timing ap-

plications. PLL operating parameters such as loop bandwidth are typically determined by optical timing requirements, and

noise reduction demands in a given system. The phase noise in the OP4008B Clock is good enough to allow the loop band-

width to be set at 100 Hz or less. Optical timing systems containing multiple or cascaded timing loops have additional con-

siderations that apply. For example, jitter peaking is often determined by VCO linearity.