2.7 R6 REGISTER

REGISTER

23

22

21

20

19

18

17

16

15

14

13

12

11

10

987654

3210

DATA[19:0]

C3

C2

C1

C0

R6

CSR[1:0]

RF_CPF[3:0]

RF_TOC[13:0]

1101

2.7.1 RF_TOC -- RF Time Out Counter and Control for FLoutRF Pin

The RF_TOC[13:0] word controls the operation of the RF Fastlock circuitry as well as the function of the FLoutRF output pin.

When this word is set to a value between 0 and 3, the RF Fastlock circuitry is disabled and the FLoutRF pin operates as a general

purpose CMOS TRI-STATE I/O. When RF_TOC is set to a value between 4 and 16383, the RF Fastlock mode is enabled and

the FLoutRF pin is utilized as the RF Fastlock output pin. The value programmed into the RF_TOC[13:0] word represents two

times the number of phase detector comparison cycles the RF synthesizer will spend in the Fastlock state.

RF_TOC

Fastlock Mode

Fastlock Period [CP events]

FLoutRF Pin Functionality

0

Disabled

N/A

High Impedance

1

Manual

N/A

Logic “0” State.

Forces all Fastlock conditions

2

Disabled

N/A

Logic “0” State

3

Disabled

N/A

Logic “1” State

4

Enabled

4X2 = 8

Fastlock

5

Enabled

5X2 = 10

Fastlock

…

Enabled

…

Fastlock

16383

Enabled

16383X2 = 32766

Fastlock

2.7.2 RF_CPF -- RF PLL Fastlock Charge Pump Current

Specify the charge pump current for the Fastlock operation mode for the RF PLL. Note that the Fastlock charge pump current,

steady state current, and CSR control are all interrelated.

RF_CPF

RF Charge Pump State

Typical RF Charge Pump Current at 3 Volts (µA)

01X

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

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