LMX24856211EVAL National Semiconductor, LMX24856211EVAL Datasheet - Page 35

• Manufacturer Part Number: LMX24856211EVAL
• Description: DELTA-SIGMA LOW POWER DUAL PLL
• Manufacturer: National Semiconductor

Specifications of LMX24856211EVAL

• Lead Free Status / Rohs Status: Not Compliant

REGISTER
2.7 R6 REGISTER
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.
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.
R6
RF_TOC
16383
…
0
1
2
3
4
5
23
CSR[1:0]
RF_CPF
10
11
12
13
14
15
0
1
2
3
4
5
6
7
8
9
22
21
RF_CPF[3:0]
20
19
Fastlock Mode
Disabled
Disabled
Disabled
Enabled
Enabled
Enabled
Enabled
Manual
18
17
RF Charge Pump State
16
DATA[19:0]
15
10X
11X
12X
13X
14X
15X
16X
1X
2X
3X
4X
5X
6X
7X
8X
9X
35
14
Fastlock Period [CP events]
13
16383X2 = 32766
RF_TOC[13:0]
12
5X2 = 10
4X2 = 8
N/A
N/A
N/A
N/A
…
11
10 9 8 7 6 5 4
Typical RF Charge Pump Current at 3
Forces all Fastlock conditions
FLoutRF Pin Functionality
Volts (µA)
High Impedance
1045
1140
1235
1330
1425
1520
Logic “0” State.
Logic “0” State
Logic “1” State
190
285
380
475
570
665
760
855
950
95
Fastlock
Fastlock
Fastlock
Fastlock
C3
3
1
C2
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2
1
C1
1
0
C0
0
1