adf4212l Analog Devices, Inc., adf4212l Datasheet - Page 11

• Manufacturer Part Number: adf4212l
• Description: Dual Low Power Pll Frequency Synthesizer
• Manufacturer: Analog Devices, Inc.

RF/IF Input Shift Register
The ADF4212L digital section includes a 24-bit input shift
register, a 14-bit IF R counter, and an 18-bit IF N counter
(comprising a 6-bit IF A counter and a 12-bit IF B counter).
Also present is a 14-bit RF R counter and an 18-bit RF N
counter (comprising a 6-bit RF A counter and a 12-bit RF B
counter). Data is clocked into the 24-bit shift register on each
rising edge of CLK. The data is clocked in MSB first. Data is
transferred from the shift register to one of four latches on the
rising edge of LE. The destination latch is determined by the
state of the two control bits (C2, C1) in the shift register. These
are the two LSBs, DB1 and DB0, as shown in the timing dia-
gram of Figure 1. The truth table for these bits is shown in
Table I. Table II shows a summary of how the latches are
programmed.
REV. A
RFCP2
IFCP2
DB23
DB23
DB23
DB23
P17
P8
RF CP CURRENT
IF CP CURRENT
SETTING
SETTING
RFCP1
IFCP1
DB22
DB22
DB22
DB22
P16
P7
RFCP0
DB21
IFCP0
DB21
DB21
DB21
PRESCALER
PRESCALER
P15
P6
RF
IF
DB20
DB20
DB20
DB20
P12
P14
P4
P5
DB19
DB19
DB19
DB19
B12
B12
P11
P3
DB18
DB18
DB18
DB18
B11
P10
B11
P2
DB17
DB17
DB17
DB17
B10
B10
P1
P9
DB16
DB16
DB16
DB16
R15
R15
B9
B9
DB15
DB15
DB15
DB15
R14
R14
B8
B8
12-BIT B COUNTER
12-BIT B COUNTER
DB14
DB14
DB14
DB14
R13
R13
B7
B7
Table II. Latch Summary
RF R COUNTER LATCH
RF N COUNTER LATCH
IF R COUNTER LATCH
IF N COUNTER LATCH
DB13
DB13
DB13
DB13
R12
R12
B6
B6
DB12
DB12
DB12
DB12
R11
R11
B5
B5
–11–
15-BIT RF REFERENCE COUNTER
DB11
DB11
DB11
DB11
R10
R10
15-BIT REFERENCE COUNTER
B4
B4
DB10
DB10
DB10
DB10
R9
B3
R9
B3
Control Bits
C2
0
0
1
1
DB9
DB9
DB9
DB9
R8
B2
R8
B2
DB8
DB8
DB8
DB8
R7
B1
R7
B1
C1
0
1
0
1
Table I. C2, C1 Truth Table
DB7
DB7
DB7
DB7
R6
A6
R6
A6
DB6
DB6
DB6
DB6
R5
A5
R5
A5
6-BIT A COUNTER
6-BIT A COUNTER
DB5
DB5
DB5
DB5
R4
A4
R4
A4
Data Latch
IF R Counter
IF N Counter (A and B)
RF R Counter
RF N Counter (A and B)
DB4
DB4
DB4
DB4
R3
A3
R3
A3
DB3
DB3
DB3
DB3
R2
A2
R2
A2
ADF4212L
DB2
DB2
DB2
DB2
R1
A1
R1
A1
C2 (0)
C2 (0)
C2 (1)
C2 (1)
DB1
DB1
DB1
DB1
CONTROL
CONTROL
CONTROL
CONTROL
BITS
BITS
BITS
BITS
C1 (0)
C1 (1)
C1 (0)
C1 (1)
DB0
DB0
DB0
DB0