www.ti.com ............................................................................................................................................. SLAS497C – AUGUST 2006 – REVISED DECEMBER 2008
When the PLL is enabled,
FSref = (PLLCLK_IN × K × R) / (2048 × P), where
P = 1, 2, 3,…, 8
R = 1, 2, …, 16
K = J.D
J = 1, 2, 3, …, 63
D = 0000, 0001, 0002, 0003, …, 9998, 9999
PLLCLK_IN can be MCLK or BCLK, selected by register 102, bits D5-D4
P, R, J, and D are register programmable. J is the integer portion of K (the numbers to the left of the decimal
point), while D is the fractional portion of K (the numbers to the right of the decimal point, assuming four digits of
precision).
Examples:
If K = 8.5, then J = 8, D = 5000
If K = 7.12, then J = 7, D = 1200
If K = 14.03, then J = 14, D = 0300
If K = 6.0004, then J = 6, D = 0004
When the PLL is enabled and D = 0000, the following conditions must be satisfied to meet specified
performance:
2 MHz
≤ ( PLLCLK_IN / P ) ≤ 20 MHz
80 MHz
≤ (PLLCLK _IN × K × R / P ) ≤ 110 MHz
4
≤ J ≤ 55
When the PLL is enabled and D
≠ 0000, the following conditions must be satisfied to meet specified
performance:
10 MHz
≤ PLLCLK _IN / P ≤ 20 MHz
80 MHz
≤ PLLCLK _IN × K × R / P ≤ 110 MHz
4
≤ J ≤ 11
R = 1
Example:
MCLK = 12 MHz and FSref = 44.1 kHz
Select P = 1, R = 1, K = 7.5264, which results in J = 7, D = 5264
Example:
MCLK = 12 MHz and FSref = 48.0 kHz
Select P = 1, R = 1, K = 8.192, which results in J = 8, D = 1920
Copyright 2006–2008, Texas Instruments Incorporated
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