669.327 MHz

Optical Timing Clock

RF Monolithics, Inc.

Phone: (972) 233-2903

Fax: (972) 387-8148

E-mail: info@rfm.com

Page 3 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

Load Recommendations for the OP4008B

The Q and Q outputs of RFM's OPB-series of SAW

clocks are AC-coupled internally. This allows customers

to set the DC level of the outputs with a simple resistor

pair on each output to drive most any application.

R1

V

R1

R2

R2

3.3V

V

Load

V

OP4005B

DC

LOAD

TUNE

1)

2)

V

R1 + R2

1 + 1 = 1

R1 R2

50

Vdc=

Load Type

Vdc

R1

R2

10k 3.3 V PECL

1.95

120

91

3.3 V

100k 3.3 V PECL

1.88

120

91

3.3 V

10k 5 V PECL

3.65

180

68

5.0 V

100k 5 V PECL

3.58

180

68

5.0 V

10k -5 V NECL

-1.30

240

62

-5.0 V

100k -5 V NECL

-1.42

240

62

-5.0 V

Vdc is the DC level desired on the outputs.

Equations 1 & 2 describe the voltage divider created by R1 & R2 and the equilivent load impedence set by the parrellel com-

bination of R1 & R2.

This will allow R1 to be expressed in terms of R2 as in equation 1. By substituting this result in equation 2, a value for R2

will result. Solving equation 1 for R1 with the known R2 is the last step.