EX-219 Datasheet, PDF (7/9 Pages) Vectron International, Inc – Hi-Reliability Evacuated Miniature Crystal Oscillator

EX-219
Hi-Reliability Evacuated Miniature Crystal Oscillator (EMXO)
causing any permanent damage. However, the maximum
temperature shall not exceed +95°C for an indefinite period of
time and, during the manufacturing process, shall not exceed
+100°C for more than 168hrs total accumulative time. If a part
has been exposed to a temperature above +95°C for a longer
duration, it might possibly accelerate internal outgassing. In
turn, it will degrade the internal vacuum pressure causing an
increase in power consumption.
Steadystate Pow er versus Case Tem perature
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-50 -25
0
25
50
75
Temperature (°C)
100 125
Figure 4
Frequency versus Case Tem perature
200
150
100
50
0
-50
-100
-50 -25
0
25
50
75 100 125
Temperature (°C)
Figure 5
5. Initial Frequency Accuracy
There are two options for defining initial frequency accuracy.
a. Fixed Frequency: This option does not have an output
frequency adjustment. The output frequency will be set to the
specified limit at time of shipment.
b. Electronic Frequency Control (EFC): This option offers
frequency adjustment with input voltage at pin #1. The EFC is
positive and monotonic as shown in Figure 6. This option will
allow the end user to adjust the output frequency closer to the
nominal frequency or to correct for long term aging. A low
noise internal voltage reference (Vref) is offered with this
option for biasing a voltage divider resistor network or DAC to
control the EFC input. Using a noisy voltage reference to
control the EFC input can degrade phase noise or ADEV
performance.
Initial frequency accuracy is not specified for the EFC option.
The EFC pull range is sufficient to correct the effects of
frequency aging over a 10 to 15 year product life.
EFC: 10MHz
2.5
1.5
0.5
-0.5
-1.5
-2.5
0.00
0.50
1.00
1.50
2.00
2.50
EFC (Volts)
Figure 6
6. Supply Ripple of Single Supply Option
Most applications require a single supply input voltage for
both the oscillator and oven circuitries. Although a voltage
reference is used to regulate the supply voltage to the
oscillator stage, the output buffer still uses the external supply
voltage directly. Thus, the supply ripple can have a direct
influence on the output signal. Figure 7 shows the typical
ripple response.
Supply Ripple (25m Vpp)
0
-20
-40
-60
-80
-100
-120
100
1,000
10,000
100,000
Ripple Frequency (Hz)
1,000,000
Figure 7
An external LC filter can be used in the supply line to
suppress the ripple amplitude. The current rating of the
inductor used in the filter shall be capable of handling high
input current especially during warm-up.
7. Dual Supply Option
The EX-219 offers a dual supply option for independent
operation of oscillator (Vosc) and oven (Voven) supply lines.
The advantages of using the dual supply option are described
below.
Vectron International • 267 Lowell Road, Hudson, NH 03051 • Tel: 1-88-VECTRON-1 • http://www.vectron.com