Temperature-compensated crystal oscillators (TCXOs) and voltage-controlled TCXOs (VCTCXOs) serve as frequency and time references in a wide range of systems, including in cellular and personal-communications-services (PCS) systems. A company once known as the supplier of tuning elements for these oscillators, Voltronics Corp. (Denville, NJ), has now added extensive lines of low-cost TCXOs and
VCTCXOs from 4 to 40 MHz. The low-power oscillators are available in both dual-in-line packages (DIPs) and standard and miniature surface-mount housings.
The initial TCXO product offerings include the 300 and 400 series, and the initial VCTCXO products are the 500 and 600 series. HCMOS or TTL (300 and 500 series) and clipped sinewave output signals (400 and 600 series) are available. Standard output frequencies are 10.0, 12.8, 13.0, 16.384, 16.8, 19.44, 20.0, 20.48, 27.0, and 38.88 MHz, with custom frequencies available from 4 to 40 MHz. All of the oscillators provide mechanical tuning of at least ±3 PPM. In addition, the 500 and 600 series oscillators include electronic frequency control over a minimum range of ±10 PPM. All of the oscillators can be set to an initial accuracy of ±1 PPM at +25°C.
All four source series can be specified for use with +3.3 or +5.0 VDC in standard and miniature SMD packages as well as 14-pin DIP packages. Frequency variations versus supply are better than ±0.2 PPM for all models for a 5-percent change in either supply.
Logic-output models in the 300 and 500 series feature maximum rise/fall time of 4 ns for HCMOS while those with the TTL options have maximum rise/fall times of 3 ns. Current consumption for these models is less than 25 mA. Models in the 400 and 600 series feature clipped sinewave outputs with similar current consumption of 25 mA. All models are offered with a wide range of standard temperature/stability levels (see table), with custom levels available. An aging rate of 1 PPM/yr is standard for all models, as is single-sideband (SSB) phase noise of better than −125 dBc/Hz offset 1 kHz from the carrier.
Voltage-controlled models in the 500 and 600 series offer electronic tuning capability of ±5 PPM for ±2.0 V centered at +2.5 VDC for a +5-VDC supply and ±1.32 V centered at +1.65 VDC for a +3.3-VDC supply. Voltronics Frequency Control Products, Inc., 100 Ford Rd., Denville, NJ 07834; (973) 586-8585, FAX: (973) 586-3404, e-mail: [email protected], Internet: www.voltronicsfcp.com.