 Crystal Oscillator Definitions |
| Nominal Frequency |
| The center or nominal output of a crystal oscillator. |
| Frequency Tolerance |
| The deviation from the nominal frequency in terms of parts per millions (PPM) at room temperature. ( 25℃±5℃) |
| Frequency Range |
| The frequency range that the oscillator type or model can be produced. |
| Frequency Stability |
| The maximum allowable frequency deviation compared to the frequency measured at 25℃ over the operating temperature range, i.e. 0℃ to +70℃. The typical stability for clock oscillator is (±50ppm). |
| Operating Temperature |
| Temperature range within which output frequency and other electrical, environmental characteristics meet the specifications. |
| Aging |
| The relative frequency change over a certain period of time. Typically, aging for clock oscillators is ±5 PPM over l year maximum. |
| Storage Temperature |
The temperature range within which the unit is safely stored without damaging or changing the performance of the unit. |
| Supply Voltage |
| The maximum voltage which can safely be applied to the VCC terminal with respect to ground. |
| Output HIGH Voltage (VOH) |
The minimum voltage at an output of the oscillator under proper loading. |
| Output LOW Voltage (VOL) |
| The maximum voltage at an output of the oscillator under proper loading. |
| Pullability (ppm) |
| The frequency shift of a VCXO as a function of control voltage. |
| Input HIGH Voltage (VIH) |
| The minimum voltage to guarantee threshold trigger at the input of the oscillator. |
| Input LOW Voltage (VIH) |
| The maximum voltage to guarantee threshold trigger at the input of the oscillator. |
| Supply Current |
| The current flowing into Vcc terminal with respect to ground. Typically supply current is measured without load. |
| Symmetry or Duty Cycle |
| The symmetry of the output waveform at the specified level (at 1.4V for TTL, at 1/2Vcc for HCMOS). |
| Rise Time (Tr) |
| The waveform rise time from Low to High transition measured at the specified level (0.4V to 2.4V for TTL and 10% to 90% for HCMOS). |
| Fall Time (Tf) |
| The waveform fall time from High to Low transition measured at the specified level (2.4V to 0.4V for TTL, and 90% to 10% for HCMOS). |
| Load/Fan Out |
The maximum load that the different families of oscillators can drive is defined as the output load driving capability. The load driving capability (Fan Out) of each family of oscillators is specified in terms of the number of gates an oscillator can drive. |
| Tri-State Enable |
| When the input pin#1 is left Open or tied to logic”1” the normal oscillation occurs. When the input pin#1 is grounded (tied to logic”0” the output is in High impedance state. The input has an internal pull-up resistor thus allowing the input pin#1 to be left open. |
| Output Logic |
| The output of an oscillator is designed to meet various specified logic’s, such as TTL, HCMOS. |
| Harmonic Distortion |
| The non-linear distortion due to unwanted harmonic spectrum component related with target signal frequency. Each harmonic component is the ratio of electric power against desired signal output electric power and is expressed in terms of dbc, e g –20dBc. Harmonic distortion specification is important especially in sine output when a clean and less distorted signal is required. |
| Start-Up Time |
The start up time of an oscillator is defined as the time an oscillator takes to reach its specified RF output amplitude. |
| |
技術支援
