SAN DIEGO Cellular phones, miniature radios and personal digital assistants on the current market are about as small as they are going to get, and the demand now is for increased performance, offering longer battery life and more features. Z-Communications Inc. claims to have addressed the demand for higher-performance voltage-controlled oscillators (VCOs) via a patented technique that improves the single-sideband-phase noise performance by about 10 dB over VCOs currently on the market.
"It used to be that the only way to get this performance was to use expensive ceramic resonator oscillators. Now you can have the high performance at the low cost the market demands," said Chuck Eapen, vice president of operations.
Z-Communications' latest VCO is the CLV1360E, targeted at low-noise digital radio applications. It generates frequencies between 1,345 to 1,375 MHz within a range of 0.5 to 4.5 Vdc of control voltage. It covers the full operating band with an average tuning sensitivity of 19 MHz/V. The device is said to deliver a clean spectral signal of -110 dBc/Hz (typical) at 10 kHz from the carrier, while attenuating the second harmonic to better than -15 dBc.
The device offers 1.1:1 linearity over frequency and temperature. Its narrow tuning range allows for quick implementation into phase-locked loops where the error voltage can be taken directly from the IC's charge-pump circuitry.
The oscillator conserves power by operating off a 5-Vdc source while drawing 21 mA (typical). It pushes less than 2.5 MHz/V within a 5 percent change of the supply voltage, and it pulls less than 2.5 MHz with a 14-dB return loss (any phase).
For those concerned with power consumption, the company offers its LPV line. The products operate off 1.2-V biases and are said to draw low current, letting the user power an AA battery for hours.
The LPV915A1 VCO, for example, is designed for 900-MHz ISM applications, in which low power and ultra-low-noise performance are required. Like the CLV1360E, the LPV915A1 provides optimum single-sideband-phase noise performance.
Both devices come in low-profile surface-mount packages. The CLV1360E measures 0.5 x 0.5 x 0.22 inch; the LPV915A1 measures 0.50 x 0.50 x 0.16 inch. Each is rated for an extended commercial temperature range of -40degrees to 85degreesC, and both are said to be suited for automated surface-mount assembly and reflow.
The CLV1360E and the LPV915A1 are priced at $24.95 each in prototyping volumes. Delivery is stock to six weeks.
Call (619) 621-2722
Issue of January 4, 1999; EETInfo No. 600