Analog Devices AD9854

AD9854
Rev. E | Page 18 of 52
CLOCK OUT = 200MHz
LPF
SIN
LPF
AD9854
COS
REFERENCE
CLOCK
COMP
A
R
A
TORS
A
OUT
= 100MHz
00636-033
Figure 33. Clock Frequency Doubler
µPROCESSOR/
CONTROLLER
FPGA, ETC.
R
SET
8-BIT PARALLEL OR
SERIAL PROGRAMMING
DATA AND CONTROL
SIGNALS
AD9854
+
REFERENCE
CLOCK
300MHz MAX DIRECT
MODE OR 15MHz TO 75MHz
MAX IN THE 4× TO 20×
CLOCK
MULTIPLIER MODE
2kΩ
I DAC
1
2
Q DAC OR
CONTROL
DAC
LOW-PASS
FILTER
LOW-PASS
FILTER
00636-034
NOTES
1. I
OUT
= APPROX 20mA MAX WHEN R
SET
= 2kΩ.
2. SWITCH POSITION 1 PROVIDES COMPLEMENTARY
SINUSOIDAL SIGNALS TO THE COMPARATOR
TO PRODUCE A FIXED 50% DUTY CYCLE FROM THE
COMPARATOR.
3. SWITCH POSITION 2 PROVIDES THE SAME DUTY CYCLE
USING QUADRATURE SINUSOIDAL SIGNALS TO THE
COMPARATOR OR A DC THRESHOLD VOLTAGE TO
ALLOW SETTING OF THE COMPARATOR DUTY CYCLE
(DEPENDS ON THE CONFIGURATION OF THE Q DAC).
CMOS LOGIC CLOCK OUT
Figure 34. Frequency Agile Clock Generator Applications for the AD9854