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R-Type Voltage Controlled Crystal Oscillators (VCXO)
The R-Type crystal oscillators are quartz-stabilized, TTL or CMOS selectable,square-wave generators. They are packaged in low-profile, hermetic ceramic, 4-pin DIPs. Long-term reliability exceeds 20 million hours mean time between failure (MTBF).

  • Frequencies to 65.536 MHz
  • TTL / CMOS compatible
  • < 20 ps rms jitter
  • Standard 14-pin DIP
  • (0/70°C or -40/+80°C)

More Information:

Pin Information

Pin # Symbol Name/Function
1 VC
VCXO: Control Voltage to modulate frequency.
7 GND Circuit and package ground.
8 Output Output waveform
14 VDD Supply voltage, 5 V ± 10%

Handling Precautions

Although protection circuitry has been designed into this device, proper precautions should be taken to avoid exposure to electrostatic discharge (ESD) during handling and mounting. VI employs a human-body model (HBM) and a charged-device model (CDM) for ESD-susceptibility testing and protection design evaluation. ESD voltage thresholds are dependent on the circuit parameters used to define the mode. Although no industry-wide standard has been adopted for the CDM, a standard HBM (resistance = 1500, capacitance = 100 pF) is widely used and therefore can be used for comparison purposes. The HBM ESD threshold presented here was obtained using these circuit parameters.

ESD Threshold Voltage

Model ESD Threshold, Minimum Unit
Human Body 1500* V
Charged Device 1500* V
* MIL-STD- 833D, Method 3015, Class 1.

Electrical Specifications

General Electrical Specifications

Parameter Symbol Min Max Unit
Supply Voltage1 VDD 4.5 5.5 V
Supply Current
(frequency dependent)
IDD 40 mA
Output Voltage Levels (VDD = 4.5 V):
Output Logic High2
Output Logic Low2
Transition Times2:
Rise Time
Fall Time
Symmetry or Duty Cycle3 SYM See Figure 14 %
Nominal Output Frequency fO 0.183 Hz 52 MHz

1 - A 0.1 µF low-frequency tantalum bypass capacitor in parallel with a 0.01 µF high-frequency ceramic capacitor is recommended.
2 - Figure 2 defines these parameters. Figure 3 illustrates the equivalent five-gate MTTL load and operating conditions under which these parameters are specified and tested.
3 - Symmetry is the ON TIME/PERIOD with VS = 2.5 V for CMOS, per Figure 2.

Absolute Pull Range (APR)

Parameter Symbol Min Max Unit
Absolute Frequency Pull Range: APR     ppm from fO
Control Voltage, VC = 0.50 - -APR - ppm from fO
Control Voltage, VC = 4.50 V - +APR - ppm from fO

Absolute pull range (APR) is specified by the fourth character of the product code. The APR is the minimum guaranteed frequency shift from fO over variations in temperature, aging, power supply, and load. Both frequency and environment limit the specified APR.

With VC between 0.5 V and 4.5 V, total pull range for the R-Type VCXO is typically between 200 ppm and 400 ppm.

A 50 ppm APR VCXO fully tracks a 50 ppm source oscillator or any other 50 ppm reference over the specified operating temperature range, life of the product, power supply and measurement variations.

Mechanical Characteristics

Parameter Value
Mechanical Shock MIL-STD-883C 2002.3 Test A
Mechanical Vibration MIL-STD-883C 2007.1 Test A
Solderability MIL-STD-883C 2003.5
Gross Leak Test MIL-STD-883C 1014.7
Fine Leak Test MIL-STD-883C 1014.7
Storage Temperature -55°C to 125°C

Oscillator Aging

Quartz-based oscillators exhibit a change in output frequency with time. Two dominant mechanisms for this phenomena are change in the stresses on the quartz resonator and mass-loading of the quartz resonator.

Changes in output frequency due to stress are a result of relaxation in the mounting stresses of the quartz resonator or transmittal of environmental stresses through the mounting arrangement. The R-Type oscillator contains a state-of-the-art miniature rectangular AT-Cut resonator, rather than the arrangement that has very little stress relaxation and isolates the quartz resonator from external stresses.

Mass-loading of the quartz resonator, which generally drives the frequency lower, is a result of outgassing of materials within a package or a lack of package hermeticity. Higher frequency resonators are more susceptible to this aging mechanism. The R-Type oscillator contains a minimum number of parts internal to the package, a monolithic IC and a quartz resonator, resulting in an internal environment that is well controlled and characterized.

Isothermal aging studies on the R-Type oscillator performed at elevated temperatures have shown a small frequency change due to mass-loading. With an application of 40° and under normal conditions, the oscillator aging is typically 2 ppm the first year, 1 ppm for the second year, and continues to logarithmically decline every ear thereafter.

Outline Diagram

Standard Frequencies

1.024 1.544 2.000 2.048 3.088 3.468 4.000
4.032 4.096 4.434 5.000 5.120 6.000 6.144
6.176 8.000 8.192 10.000 10.240 10.762 11.059
12.000 12.288 12.352 12.960 14.318 14.745 15.000
15.360 15.440 16.000 16.384 17.168 18.000 18.432
18.528 19.440 19.660 20.000 20.275 20.480 21.500
22.759 23.160 23.602 24.000 24.293 24.576 24.704
25.000 25.175 25.197 27.000 27.648 27.750 28.346
28.672 29.538 32.000 32.768 34.368 34.406 34.880
37.056 38.321 44.736 45.000 45.250 51.840 52.000
39.3216 35.328 65.536        
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