LMX2430_16 Datasheet, PDF (38/53 Pages) Texas Instruments – Dual High-Frequency Synthesizer

LMX2430, LMX2433, LMX2434
SNAS187D – FEBRUARY 2003 – REVISED JANUARY 2016
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9.6.5.2.1 IF_P - IF Synthesizer Prescaler Select (R4[22])
The LMX243x IF synthesizer uses a selectable dual modulus prescaler. An 8/9 or a 16/17 prescale ratio can be
selected.
CONTROL BIT
IF_P
Table 36. IF Prescaler Select Bit
REGISTER LOCATION
DESCRIPTION
R4[22]
IF Prescaler Select
FUNCTION
0
1
8/9 Prescaler Selected 16/17 Prescaler Selected
9.6.5.3 IF_PD - IF Synthesizer Power Down (R4[23])
The IF_PD bit is used to switch the IF PLL between a powered-up and powered-down mode.
Furthermore, the IF_PD bit operates in conjuction with the IF_CPT bit to set a synchronous or an asynchronous
power-down mode. Refer to IF_CPT - IF Synthesizer Charge-Pump Tri-State (R3[20]) for more details on how to
program the IF_CPT bit.
CONTROL BIT
IF_PD
Table 37. IF PLL Powerdown Bit
REGISTER LOCATION
DESCRIPTION
R4[23]
IF Power down
0
IF PLL Active
FUNCTION
1
IF PLL Power down
9.6.6 R5 Register
The R5 Register contains the IF_TOC control word. The IF_TOC is used to set up the fastlock circuitry of the IF
synthesizer. The IF_TOC is a 12-bit binary counter programmable from 0 to 4095.
Table 38. R5 Register
REG 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[20:0] FIELD
ADDRESS
[2:0]
FIELD
R5 0 0 0 0 0 0 0 0 0
IF_TOC[11:0]
101
38
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