Uncompromised Clocking Solution for 16-Bit 2.5Gsps
High Performance DAC
Design Note 555
Clarence Mayott
Introduction
The LTC В®2000 16-bit 2.5Gsps DAC offers excellent
AC performance. For many DAC applications, phase
noise, noise spectral density (NSD), and spurious
free dynamic range (SFDR) are critical to maximize
the number of possible channels in a band without
eroding the signal to noise ratio (SNR) in the band
of interest. High speed DACs require a clean sample
clock to achieve the best possible noise and spurious
performance. Using the ultralow noise and spurious
LTC6946 PLL synthesizer as a clock source for the
LTC2000 maximizes system performance (FigureВ 1). 16-Bit High Speed DAC
The high spectral purity and low noise of the LTC2000
make it an excellent signal generator. FigureВ 2 highlights the excellent additive phase noise performance
of the LTC2000 of –165dBc/Hz at 1MHz offset and
–147dBc/Hz at 10kHz offset with a 65MHz output. For
output frequencies up to 100MHz, the LTC2000 has
NSD better than –166dBm/Hz and SFDR better than
76dB. For higher output frequencies up to 1GHz, the …