1FEATURES
2· Single 3.3-V Supply
· High-Performance Clock Generator,
Incorporating Crystal Oscillator Circuitry with
Integrated Frequency Synthesizer
· Low Output Jitter: As low as 380 fs (RMS
integrated between 10 kHz to 20 MHz)
· Low Phase Noise at 312.5 MHz:
– Less than –120 dBc/Hz at 10 kHz and
–147 dBc/Hz at 10-MHz offset from carrier
· Supports Crystal or LVCMOS Input
Frequencies at 31.25 MHz, 33.33 MHz, and
35.42 MHz
· Output Frequencies: 100 MHz, 106.25 MHz,
125 MHz, 156.25 MHz, 212.5 MHz, 250 MHz, and
312.5 MHz
· Differential Low-Voltage Positive Emitter
Coupled Logic (LVPECL) Outputs
· Fully-Integrated Voltage-Controlled Oscillator
(VCO): Runs from 1.75 GHz to 2.35 GHz
· Typical Power Consumption: 300 mW
· Chip Enable Control Pin
· Available in 4-mm × 4-mm QFN-24 Package
· ESD Protection Exceeds 2 kV (HBM)
· Industrial Temperature Range: –40°C to +85°C

APPLICATIONS
· Low-Cost, Low-Jitter Frequency Multiplier

DESCRIPTION
The CDC421Axxx is a high-performance,
low-phase-noise clock generator. It has an integrated
low-noise, LC-based voltage-controlled oscillator
(VCO) that operates within the 1.75 GHz to 2.35 GHz frequency range. It has an integrated crystal oscillator
that operates in conjunction with an external AT-cut
crystal to produce a stable frequency reference for a
phase-locked loop (PLL)-based frequency
synthesizer. The output frequency (fOUT) is
proportional to the frequency of the input crystal (fXTAL).
The device operates in 3.3-V supply environment and
is characterized for operation from –40°C to +85°C. The CDC421Axxx is available in a QFN-24 4-mm ×
4-mm package.
The CDC421Axxx differs from the CDC421xxx in the following ways:
· Device Startup
The CDC421Axxx has an improved startup circuit
to enable correct operation for all power-supply
ramp times.