AD9553 View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
AD9553
Analog Devices
AD9553 Datasheet PDF : 44 Pages
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AD9553
The Ax pins allow the user to select one of fifteen input reference
frequencies as shown in Table 14. The device sets the appropriate
divide-by-5 (÷5A, ÷5B), multiply-by-2 (×2A, ×2B), and input
divider (RA, RB, RXO) values based on the logic levels applied
to the Ax pins.
The same settings apply to both the REFA and REFB input
paths. Furthermore, the ÷5, ×2, and R values cause the PLL
input frequency to be either 16 kHz or 40/3 kHz. There are two
exceptions. The first is for Pin A3 to Pin A0 = 1101, which
yields a PLL input frequency of 155.52/59 MHz. The second is for
Pin A3 to Pin A0 = 1110, which yields a PLL input frequency of
either 1.5625 MHz or 4.86 MHz depending on the Yx pins.
Note that the XTAL input is not available for holdover func-
tionality in the A3 to A0 = 1101 and 1110 pin configurations,
thus the undefined RXO value.
The Yx pins allow the user to select one of 52 output frequency
combinations (fOUT1 and fOUT2) per Table 15. The device sets the
appropriate P0, P1, and P2 settings based on the logic levels applied
to the Yx pins. Note, however, that selections 101101 through
110010 require Pin A3 to Pin A0 = 1101, and selection 110011
requires Pin A3 to Pin A0 = 1110.
The value (N) of the PLL feedback divider and the control
setting for the charge pump current (CP) depend on a combi-
nation of both the Ax and Yx pin settings as shown in Table 16.
Table 14. Pin Configured Input Frequency, Ax Pins1
Pin A3 to Pin A0
0000
fREFA, fREFB (MHz)
Divide-by-5A,
Divide-by-5B
0001
0.008
Bypassed
0010
1.536
Bypassed
0011
2.048
Bypassed
0100
16.384
Bypassed
0101
01102
19.44
25
Bypassed
Bypassed
0111
38.88
Bypassed
1000
61.44
Bypassed
1001
77.76
Bypassed
1010
122.88
Bypassed
1011
125
On
1100
11013
11104
1.544
155.52
25 or 77.76
Bypassed
Bypassed
Bypassed
1111
200/3
Bypassed
×2A, ×2B
SPI mode
On
Bypassed
Bypassed
Bypassed
Bypassed
On
Bypassed
Bypassed
Bypassed
Bypassed
On
On
Bypassed
Bypassed
Bypassed
RA, RB (Decimal)
1
96
128
1024
1215
3125
2430
3840
4860
7680
3125
193
59
16
5000
RXO (Decimal)
3125
3125
3125
3125
3125
3125
3125
3125
3125
3125
3125
3125
Undefined
Undefined
3750
1 For divide-by-5 and ×2 frequency scalers, “On” indicates active.
2 Using A0 to A3 = 0110 to yield a 25 MHz to 125 MHz conversion provides a loop bandwidth of 170 Hz. An alternate 25 MHz to 125 MHz conversion uses A0 to A3 = 1110, which
provides a loop bandwidth of 20 kHz.
3 Pin A3 to Pin A0 = 1101 only works with Pin Y5 to Pin Y0 =101101 through 110010.
4 Pin A3 to Pin A0 = 1110 only works with Pin Y5 to Pin Y0 =110011 or 111111.
Rev. A | Page 17 of 44
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