Datasheet

AD9858
Rev. C | Page 27 of 32
APPLICATIONS INFORMATION
DAC
FILTER
PHASE/
FREQUENCY
DETECTOR
150MHz
DIVIDER
1/2/4
DIVIDER
1/2
ANALOG
MIXER
CHARGE PUMP
0.5mA TO 2mA
(0.5mA STEPS)
LOOP
FILTER
FIXED
LOOP
(LO1)
DDS
1GSPS
FREQUENCY
TUNING WORD
DC TO 400MHz
2GHz
2GHz ±150MHz
AD9858
2GHz
DDS/DAC
CLOCK 1000MHz
f
REF
DC TO 150MHz
1032
FILTER
VCO
03166-040
Figure 37. DDS Synthesizer Translation Loop Oscillator (Implemented in Translation Loop Evaluation Board)
DAC
FILTER
PHASE/
FREQUENCY
DETECTOR
150MHz
DIVIDER
1/2/4
CHARGE PUMP
0.5mA TO 2mA
(0.5mA STEPS)
LOOP
FILTER
DDS
1GSPS
FREQUENCY
TUNING WORD
DC TO 400MHz
VCO
DDS/DAC CLOCK
AD9858
F = M × f
REF
f
REF
DC TO 150MHz
1032
DIVIDER
0
3166-041
Figure 38. DDS Synthesizer Single-Loop PLL Up-Conversion
DAC
FILTER
PHASE/
FREQUENCY
DETECTOR
150MHz
DDS
1GSPS
DIVIDER
1/2/4
DIVIDER
1/2
CHARGE PUMP
0.5mA TO 2mA
(0.5mA STEPS)
LOOP
FILTER
150MHz
REFERENCE
FREQUENCY
TUNING WORD
150MHz
1000
MHz
VCO
2GHz MAX
AD9858
32
03166-042
Figure 39. DDS Synthesizer AD9858 as Fractional N Synthesizer (Implemented in Fractional Divide Evaluation Board)