AOCJY OCXO Vref

AOCJY OCXO APPLICATION NOTE
REFERENCE VOLTAGE OUTPUT
Figure (1)
Vc (Control Voltage)
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1
R1
2
R2
5
GND
AOCJY OCXO
Vref
Vdd
5
TOP View
3
RF Output
4
GND
AOCJY OCXO
Vref
10k
1
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AOCJY devices also provide a Regulated DC output on
pin # 2 (Vref ). The value of this voltage is dependent
upon the Supply Voltage bias. For instance, for
Vdd = 5.0V; the Vref value will be +4.50V ±0.2V. Similarly for Vdd = 3.3V; the Vref value will be +2.80V ±0.2V.
Vc (Control Voltage)
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These devices are suitable for ROHS compliant reflow
and incorporate a Control Voltage (Vc) port; providing
a means to set these devices on frequency, post reflow.
Another way to achieve a similar result is to use a two
resistor – potential divider approach, as shown in
figure (2) below.
Figure (2)
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The AOCJY series of Oven Controlled Crystal Oscillators are designed to facilitate reference frequencies
from 10.00MHz to 100MHz carrier.
25.4 x 22.1 x 12.5 mm
2
Vdd
3
TOP View
RF Output
4
In this approach, the Vc Voltage will be given by:
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Vc = (R2 / (R1+R2)) * Vref
As depicted in figure (1), the simplest way to utilize the
Vref output is to connect a potentiometer between
Vref and Gnd. The “wiper” of the potentiometer
should then be connected to the Vc (Control Voltage
port) of the OCXO. This way, the DC Voltage value
@ Vc port can be adjusted by varying the position of
the wiper.
As shown, R2 can either be fixed or a variable resistor.
Good starting values for a 3.3V biased OCXO’s could be
R1= 6.98 kΩ and R2 = 10.00 kΩ
Similarly, for 5.0V biased OCXO’s, R1 = 8.06 kΩ and
R2 = 10.00 kΩ could yield the desired result. If a potentiometer is used in place of R2, the “wiper” should be
connected to the Vc port to provide variable resistance.
Please take note that the by-pass capacitors on both
the Vdd port, as well as the Vc port are merely
suggested values to help improve noise suppression.
If you have specific questions, please contact us at
[email protected]
NOTE: Abracon manufactured products are intended for general commercial and industrial use. For applications requiring
high reliability and/or presenting extreme operating environment, written consent & authorization from Abracon is required.
ABRACON IS
ISO9001:2008
CERTIFIED
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30332 Esperanza, Rancho Santa Margarita, California 92688
tel 949-546-8000 | fax 949-546-8001 | www.abracon.com
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