DOCXO Double Oven Controlled Quartz Crystal Oscillators
Model FE-205A
Model FE-405A
Model FE-505A

Analog or Digital Interface (LSB "1.7 x10-14)
Excellent Temperature Stability <1 x10-10
-40° C to +75° C Operation
Low Aging <5 x10-8 for 10 yrs.
Retrace 1x10-10 after 1 hour, 24 hrs off
Any frequency 5 MHz to 25 MHz

Typical Applications

  • Cellular Base Stations
  • Test Equipment
  • Stratum Clocks
  • GPS Timing Systems
  • Rubidium Replacement




FE-405A, FE-505A
Function Description   FE-205A, FE-405A, FE-505A
Technical Characteristics

This new design concept features a precision double oven crystal oscillator capable of analog or digital tuning. The serial digital tuning is ideal for disciplined applications in today’s telecommunications industry where holdover is important. The temperature coefficient of this device is less than 1x10-10. This is accomplished with no over or under shoot, with fast temperature slew rates of 4°C per minute. Performance is Determined by a Double Oven SC Cut 5 th Overtone Crystal. Output Frequency is Digitally Synthesized.

Technical Highlights
Superior crystal oscillator precision is required for both time and frequency in precision instrument applications such as synthesizers, counters and spectrum analyzers. The same high end performance characterisics are required in satellite transmissions, geophysical survey positioning systems, and standard time/time-interval generation and transfer. Using breakthrough design and packaging concepts, FEI has applied advanced technologies to create the best of both worlds... with small size and low costs. This makes the FE-205A, FE- 405A, and FE-505A your best choices for applications in which it is essential to combine excellent spectral purity with short- and long-term stability.

Physical Characteristics
FE-205A 2.00" x 2.00" x 1.50"
FE-405A 3.01" x 3.03" x 1.44"
FE-505A 2.98" x 2.80" x 0.89"
Supply Voltage

+15v DC 5%, l amp max
+5v DC5%, 200ma

Option 20 for single 15v input
Warm-Up Power 7W, max
Steady State 3.5W Max at 25C
Operating Temperature Range -40C to +75C
meets all specifications
Temperature Range
-55C to +85C may not meet freq. stability

Options Available
Option 20 15V DC - Input
Option 28 Aging 2.5x10-11/day after 15 days of continuous Operation
Option 30 Analog Tuning (0V to 10V)
* Contact factory for specials including custom packages


10MHz and 15MHz Standard (Option for any other frequency 5 to 25MHz)
RF Output
  • Level: 9dBm 2dBm into 50 ohm load
  • Waveform: Sine wave
  • Harmonics: -40dBc max
  • Spurious: -65dBc to 1 GH
Allan Variance
(Short Term Frequency Stability)
t=1 second (1 x 10-11)
t=10 second (2 x 10-12)
t=100 second (1 x 10-12)
Long Term Stability 5 x 10-10 /day, 5 x 10-8 /year
Frequency Temperature Stability <1 x 10 -10 (-40° C to +75° C) (Including frequency over or undershoot at any fast or slow temperature slew rate)
Phase Noise
1 KHz
10 KHz -145dBc/Hz
Per Day <1 x 10 (after 14 days continuous operation)
Typical 5 x 10 -11
Per Year <1 x 10 -8
Per 10 Years <5 x 10 -8
Frequency Retrace

1 x 10-10 in 1 hr. after 24 hours power off

5 x 10-10 in 20 min. after 24 hours power off

G-Sensitivity 2 x 10-9 per G, any axis
Input Voltage 15 VDC 5%
Input Voltage Sensitivity 1 x 10-9 for 5%
Digital Frequency Adjustment: Standard
RF Output Frequency Adjustment:

Digital control Via TTL serial port interface. For detail see Manual.

Serial Communication 9600 Baud, TTL level, 8 bits, no parity, 1 stop bit

Adjustment resolution

LSB 1.7 x 10-14

Adjustment Range • 20Hz for 15MHz output
• 9.5Hz for 10MHz output
(Other trim ranges can be special ordered)
Analog Frequency Adjustment: Option 30
Coarse Adjust Range 2.4 x 10-7 Via DC input of 5v5v (0 to +10v)
Fine Adjust Range 0.5 x 10-8 Via DC input of 5v5v (0 to +10v)