Packaging information
| Package | Pins VQFNP (RTC) | 48 |
| Operating temperature range (°C) -40 to 85 |
| Package qty | Carrier 250 | SMALL T&R |
Features for the LMX2820
- Output frequency: 45 MHz to 22.6 GHz
- 36-fs rms jitter (12 kHz – 95 MHz) at 6 GHz
- High-performance PLL
- Figure of merit: –236 dBc/Hz
- Normalized 1/f noise: –134 dBc/Hz
- -95 dBc Integer Mode Spurs (fPD=100 MHz)
- High phase detector frequency
- 400-MHz integer mode
- 300-MHz fractional mode
- Programmable input multiplier
- Direct PFD input for offset mixing support allowing PLL N divider to be one for ultra-low jitter
- 2.5-µs fast VCO calibration time
- Mute pin with 200-ns mute/unmute time
- –45-dBc VCO leakage with doubler enabled
- Support for external VCO up to 22.6-GHz
- Synchronization of output phase across multiple devices
- Two differential RF outputs and one differential SYSREF output for JESD204B support
Description for the LMX2820
The LMX2820 is a high-performance, wideband synthesizer that can generate any frequency in the range of 45 MHz to 22.6 GHz. The high performance PLL with figure of merit of –236 dBc/Hz and high phase detector frequency can attain very low in-band noise and integrated jitter. The high-speed N-divider has no pre-divider, thus significantly reducing the amplitude and number of spurs. There is also a programmable input multiplier to mitigate integer boundary spurs.
The LMX2820 allows users to synchronize the output of multiple devices and also enables applications that need deterministic delay between input and output. The fast calibration algorithm greatly reduces the VCO calibration time, enabling systems requiring fast frequency hopping. The LMX2820 can generate or repeat SYSREF that is compliant to the JESD204B standard, allowing for its use as a low-noise clock source for high-speed data converters. This synthesizer can also be used with an external VCO. A direct PFD input pin is provided to support offset mixing for low spurious transmission.
The device runs from a single 3.3-V supply and has integrated LDOs that eliminate the need for onboard low-noise LDOs.