LMX2522 Datasheet, PDF (14/18 Pages) National Semiconductor (TI) – PLLatinum Frequency Synthesizer System with Integrated VCOs

Programming Description (Continued)
R2 REGISTER
The R2 Register address bits (R2 [1:0]) are “10”.
The IF_CUR [1:0] bits program the IF charge pump current. Considering the external IF VCO and loop filter, the user can select
the amount of IF charge pump current to be 100µA, 200µA, 300µA or 800µA.
R2 REGISTER
MSB
SHIFT REGISTER BIT LOCATION
LSB
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 Field
Address
Field
R2
IF_
0 0 1 0 0 1 1 1 0 1 1 0 101000101 0
(Default) CUR[1:0]
Name
IF_CUR [1:0]
Functions
IF Charge Pump Current
00 = 100 µA
01 = 200 µA
10 = 300 µA
11 = 800 µA
www.national.com
14