Vectron International • 267 Lowell Road, Hudson, NH 03051 • Tel: 1-88-VECTRON-1 • http://www.vectron.com

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VCXO Feature: The VT-501 can be ordered with a VCXO function for applications were it will be used in a PLL, or the output frequency

needs fine tune or calibration adjustments. This is a high impedance input , 1Mohm, and can be driven with an op-amp or terminated with

adjustable resistors etc. Pin 1 should not be left floating on the VCXO optional device.

“No Adjust” Option: In applications were the VT-501 will not be used in a PLL , or the output frequency does not need fine tune

adjustments, the best device to use would be a VT-501-xxx-xxx0. By using the “no adjust” option, the circuit is simplified as Vc does not

need to be adjusted or set to a predetermined voltage and pin 1 should be grounded (pin 1 can be left open but should not be set to a

voltage such as an RF signal or power supply voltage.

Figure 3 Phase Noise Plot for a 10.000MHz output

VCXO Function

Phase Noise and Alan Deviation Plot

Test Circuit

I

DD

V

DD

V

C

I

C

15pF

4

12

3

.1μF

.01μF

+

-

+

-

t

R

t

F

V

OH

V

OL

50%

On Time

Period

Figure 1 Test Circuit

Figure 2 Duty Cycle, On Time/Period

Figure 4 Alan Deviation Plot for a 10.000MHz output