LMX2486
SNAS324 –JANUARY 2006
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RF_CPG -- RF PLL Charge Pump Gain
This is used to control the magnitude of the RF PLL charge pump in steady state operation.
RF_CPG Charge Pump State Typical RF Charge Pump Current at 3
Volts (µA)
0 1X 95
1 2X 190
2 3X 285
3 4X 380
4 5X 475
5 6X 570
6 7X 665
7 8X 760
8 9X 855
9 10X 950
10 11X 1045
11 12X 1140
12 13X 1235
13 14X 1330
14 15X 1425
15 16X 1520
ACCESS -- Register Access word
It is mandatory that the first 5 registers R0-R4 be programmed. The programming of registers R5-R7 is optional.
The ACCESS[3:0] bits determine which additional registers need to be programmed. Any one of these registers
can be individually programmed. According to the table below, when the state of a register is in default mode, all
the bits in that register are forced to a default state and it is not necessary to program this register. When the
register is programmable, it needs to be programmed through the MICROWIRE. Using this register access
technique, the programming required is reduced up to 50%.
ACCESS Bit Register Location Register Controlled
ACCESS[0] R3[20] R4
ACCESS[1] R3[21] R5
ACCESS[2] R3[22] R6
ACCESS[3] R3[23] R7
The default conditions the registers is shown below:
Register 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Data[19:0] C3 C2 C1 C0
R4 0 0 0 0 0 0 1 0 1 1 0 0 0 1 1 1 0 0 0 0 1 0 0 1
R5 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 1 1
R6 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 0 1
R7 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 1 0 0 0 0 1 1 1 1
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