AD9517-1 Analog Devices, Inc., AD9517-1 Datasheet - Page 29

• Manufacturer Part Number: AD9517-1
• Description: 12-output Clock Generator With Integrated 2.5 Ghz Vco
• Manufacturer: Analog Devices, Inc.

Internal VCO and Clock Distribution
When using the internal VCO and PLL, the VCO divider
must be employed to ensure that the frequency presented to
the channel dividers does not exceed its specified maximum
frequency (1600 MHz, see Table 3). The internal PLL uses an
external loop filter to set the loop bandwidth. The external loop
filter is also crucial to the loop stability.
When using the internal VCO, it is necessary to calibrate the
VCO (0x18<0>) to ensure optimal performance.
For internal VCO and clock distribution applications, the
register settings shown in Table 24 should be used.
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Table 24. Settings When Using Internal VCO
Register
0x10<1:0> = 00b
0x10 to 0x1E
0x18<0> = 0,
0x232<0> = 1
0x18<0> = 1,
0x232<0> = 1
0x1E0<2:0>
0x1E1<0> = 0b
0x1E1<1> = 1b
Function
PLL normal operation (PLL on).
PLL settings. Select and enable a reference
input; set R, N (P, A, B), PFD polarity, and I
according to the intended loop configuration.
Reset VCO calibration (first time after
power-up, this does not have to be done,
but must be done subsequently).
Initiate VCO calibration.
VCO divider set to divide-by-2, divide-by-3,
divide-by-4, divide-by-5, and divide-by-6.
Use the VCO divider as source for
distribution section.
VCO selected as the source.
AD9517-1
CP