WM8310GEB/V Wolfson Microelectronics, WM8310GEB/V Datasheet - Page 49

• Manufacturer Part Number: WM8310GEB/V
• Description: POWER MANAGEMENT SUBSYSTEM, 169BGA
• Manufacturer: Wolfson Microelectronics

Specifications of WM8310GEB/V

• Supply Voltage: 7V
• No. Of Step-down Dc - Dc Converters: 4
• No. Of Ldo Regulators: 11
• Digital Ic Case Style: BGA
• No. Of Pins: 169
• No. Of Regulated Outputs: 13
• Operating Temperature Range: -40°C To
• Rohs Compliant: Yes
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Pre-Production
w
In order to follow the above requirements for F
according to the desired output F
range 90-100MHz. The available divisions are integers from 4 to 64. Some typical settings of
FLL_OUTDIV are noted in Table 18.
Table 18 Selection of FLL_OUTDIV
The value of FLL_FRATIO should be selected as described in Table 19.
Table 19 Selection of FLL_FRATIO
In order to determine the remaining FLL parameters, the FLL operating frequency, F
calculated, as given by the following equation:
The value of FLL_N and FLL_K can then be determined as follows:
See Table 20 for the coding of the FLL_OUTDIV and FLL_FRATIO fields.
Note that F
In FLL Fractional Mode, the fractional portion of the N.K multiplier is held in the FLL_K register field.
This field is coded as a fixed point quantity, where the MSB has a weighting of 0.5. Note that, if
desired, the value of this field may be calculated by multiplying K by 2^16 and treating FLL_K as an
integer value, as illustrated in the following example:
For best FLL performance, the FLL fractional mode is recommended. Therefore, if the calculations
yield an integer value of N.K, then it is recommended to adjust FLL_OUTDIV in order that N.K is a
non-integer value. Care must always be taken to ensure that the FLL operating frequency, F
within its recommended limits of 90-100 MHz.
2.8125 MHz - 3.125 MHz
3.75 MHz - 4.1667 MHz
5.625 MHz - 6.25 MHz
11.25 MHz - 12.5 MHz
18 MHz - 20 MHz
22.5 MHz - 25 MHz
1MHz - 13.5MHz
256kHz - 1MHz
128kHz - 256kHz
64kHz - 128kHz
Less than 64kHz
REFERENCE FREQUENCY F
OUTPUT FREQUENCY F
F
N.K = F
If N.K = 8.192, then K = 0.192.
Multiplying K by 2^16 gives 0.192 x 65536 = 12582.912 (decimal) = 3126 (hex).
REF
VCO
is the input frequency, after division by FLL_CLK_REF_DIV, where applicable.
= (F
VCO
OUT
/ (FLL_FRATIO x F
x FLL_OUTDIV)
OUT
OUT
REF
. The divider, FLL_OUTDIV, must be set so that F
REF
011111 (divide by 32)
010111 (divide by 24)
001111 (divide by 16)
000111 (divide by 8)
000100 (divide by 5)
000011 (divide by 4)
000 (divide by 1)
001 (divide by 2)
010 (divide by 4)
011 (divide by 8)
100 (divide by 16)
)
VCO
, the value of FLL_OUTDIV should be selected
FLL_OUTDIV
FLL_FRATIO
PP, December 2009, Rev 3.0
VCO
WM8310
VCO
, must be
is in the
VCO
, is
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