Preliminary

DFBM-CS320

Data Sheet

May 18, 2005

Proprietary Information and Specifications are Subject to Change

External Reference Clock Input

The DFBM-CS320 RF local oscillator and internal digital clocks are derived from the reference

clock at DFBM-CS320 XTAL_IN input. This reference may be either an external clock or from a

crystal connected between XTAL_IN and XTAL_OUT.

The external clock can either be a digital level square wave or sinusoidal and this may be

directly coupled to XTAL_IN without the need for additional components. If the peaks of the

reference clock are below 0 V or above 1.8 V, it must be driven through a DC blocking capacitor

(~33pF) connected to XTAL_IN.

The external clock signal should meet the specifications as below table.

Min

Typ

Max

Frequency

7.5 MHz

16 MHz

40 MHz

Duty cycle

20 : 80

50 : 50

80 : 20

Edge Jitter (At Zero Crossing)

-

-

15ps rms

Signal Level

400mV pk-pk

-

1.8V *

* If the external clock is driven through a DC blocking capacitor then maximum allowable

amplitude is reduced from 1.8V to 800mV pk-pk.