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LANSDALE Semiconductor, Inc.

ML145145

RECOMMENDED READING

Technical Note TN–24, Stated Corp.

Technical Note TN–\7, Stated Corp.

E. Hafner, “The Piezoelectric Crystal Unit – Definitions and

Method of Measurement”, Proc IEEE, Vol. 57, No. 2 Feb.,

1969

D. Kemper, L. Rosine, “Quartz Crystals for Frequency

Control”, Electro–Technology, June, 1969.

P.J. Ottowitz, “A Guide to Crystal Selection”, Electronic

Design, May, 1966.

LEGACY APPLICATIONS

The features of the ML145145 permit bus operation with a

dedicated wire needed only for the strobe input. In a micro-

processor–controlled system this strobe input is accessed when

the PLL is addressed. The remaining data and address inputs

will directly interface to the microprocessor’s data and address

buses.

The ÷ R programability is used to advantage in Figure 10.

Here, the nominal ÷ R value is 3667, but by programming

small changes in this value, fine tuning is accomplised. Better

tuning resolution is achievable with this method than by chang-

ing the ÷ N due to the use of the large fixed prescaling value

of ÷ 256 provided by the ML12079.

The two–loop synthesizer, in Figure 11, takes advantage of

these features to control the phase–locked loop with a minu-

mum of dedicated lines while preserving optimal loop per-

formance. Both 25 Hz and 100 Hz steps are provided while the

relatively large reference frequencies of 10 Khz or 10.1 kHz

are maintained.

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