AD9520-5BCPZ-REEL7 Analog Devices Inc, AD9520-5BCPZ-REEL7 Datasheet - Page 33
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AD9520-5BCPZ-REEL7
Manufacturer Part Number
AD9520-5BCPZ-REEL7
Description
12/24-Output Clock Generator
Manufacturer
Analog Devices Inc
Type
Clock Generator, Fanout Distributionr
Datasheet
1.AD9520-5BCPZ.pdf
(80 pages)
Specifications of AD9520-5BCPZ-REEL7
Design Resources
Synchronizing Multiple AD9910 1 GSPS Direct Digital Synthesizers (CN0121) Phase Coherent FSK Modulator (CN0186)
Pll
Yes
Input
CMOS, LVDS, LVPECL
Output
CMOS, LVPECL
Number Of Circuits
1
Ratio - Input:output
2:12, 2:24
Differential - Input:output
Yes/Yes
Frequency - Max
2.4GHz
Divider/multiplier
Yes/No
Voltage - Supply
3.135 V ~ 3.465 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
64-LFCSP
Frequency-max
1.6GHz
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
R and N Divider Delays
Both the R and N dividers feature a programmable delay cell.
These delays can be enabled to allow adjustment of the phase
relationship between the PLL reference clock and the VCO or
CLK. Each delay is controlled by three bits. The total delay
range is about 1 ns. See 0x019 in Table 2 and Table 48.
Digital Lock Detect (DLD)
By selecting the proper output through the mux on each pin, the
DLD function is available at the LD, STATUS, and REFMON pins.
The digital lock detect circuit indicates a lock when the time
difference of the rising edges at the PFD inputs is less than a
specified value (the lock threshold). The loss of a lock is indicated
when the time difference exceeds a specified value (the unlock
threshold). Note that the unlock threshold is wider than the
lock threshold, which allows some phase error in excess of the
lock window to occur without chattering on the lock indicator.
The lock detect window timing depends on the value of the
CPRSET resistor, as well as three settings: the digital lock
detect window bit (0x018[4]), the antibacklash pulse width
bit (0x017[1:0], see Table 2), and the lock detect counter
(0x018[6:5]). The lock and unlock detection values in Table 2
are for the nominal value of CPRSET = 5.11 kΩ. Doubling the
CPRSET value to 10 kΩ doubles the values in Table 2.
Table 25. How a 10 MHz Reference Input Can Be Locked to Any Integer Multiple of N
f
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
1
REF
X = don’t care.
(MHz)
R
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
P
1
2
1
1
1
2
2
2
2
2
2
2
2
2
2
4
4
A
X
X
X
X
X
X
0
1
2
1
X
0
1
X
0
0
1
1
1
1
1
1
1
1
1
B
1
1
3
4
5
3
3
3
3
4
5
5
5
6
6
3
3
N
1
2
3
4
5
6
6
7
8
9
10
10
11
12
12
12
13
f
10
20
30
40
50
60
60
70
80
90
100
100
110
120
120
120
130
VCO
(MHz)
Rev. 0 | Page 33 of 80
Mode
FD
FD
FD
FD
FD
FD
DM
DM
DM
DM
FD
DM
DM
FD
DM
DM
DM
A lock is not indicated until there is a programmable number of
consecutive PFD cycles with a time difference less than the lock
detect threshold. The lock detect circuit continues to indicate a
lock until a time difference greater than the unlock threshold
occurs on a single subsequent cycle. For the lock detect to work
properly, the period of the PFD frequency must be greater than
the unlock threshold. The number of consecutive PFD cycles
required for a lock is programmable (0x018[6:5]).
Note that it is possible in certain low (<500 Hz) loop bandwidth,
high phase margin cases that the DLD can chatter during acqui-
sition, which can cause the AD9520 to automatically enter and exit
holdover. To avoid this problem, it is recommended that the
user make provisions for a capacitor to ground on the LD pin so
that current source digital lock detect (CSDLD) mode can be used.
Notes
P = 1, B = 1 (bypassed)
P = 2, B = 1 (bypassed)
P = 1, B = 3
P = 1, B = 4
P = 1, B = 5
P = 2, B = 3
P and P + 1 = 2 and 3, A = 0, B = 3
P and P + 1 = 2 and 3, A = 1, B = 3
P and P + 1 = 2 and 3, A = 2, B = 3
P and P + 1 = 2 and 3, A = 1, B = 4
P = 2, B = 5
P and P + 1 = 2 and 3, A = 0, B = 5
P and P + 1 = 2 and 3, A = 1, B = 5
P = 2, B = 6
P and P + 1 = 2 and 3, A = 0, B = 6
P and P + 1 = 4 and 5, A = 0, B = 3
P and P + 1 = 4 and 5, A = 1, B = 3
AD9520-5