Datasheet

ADF4107 Data Sheet
Rev. D | Page 10 of 20
HI
HI
D1
D2
Q1
Q2
CLR2
CP
U1
U2
UP
DOWN
ABP2
ABP1
CPGND
U3
R DIVIDER
PROGRAMMABLE
DELAY
N DIVIDER
V
P
CHARGE
PUMP
03338-020
CLR1
Figure 20. PFD Simplified Schematic and Timing (in Lock)
MUXOUT AND LOCK DETECT
The output multiplexer on the ADF4107 allows the user to
access various internal points on the chip. The state of
MUXOUT is controlled by M3, M2, and M1 in the function
latch. Figure 25 shows the full truth table. Figure 21 shows the
MUXOUT section in block diagram form.
Lock Detect
MUXOUT can be programmed for two types of lock detect:
digital lock detect and analog lock detect.
Digital lock detect is active high. When the lock detect
precision (LDP) bit in the R counter latch is set to 0, digital lock
detect is set high when the phase error on three consecutive
phase detector (PD) cycles is less than 15 ns. With LDP set to 1,
five consecutive cycles of less than 15 ns are required to set the
lock detect. It stays set high until a phase error of greater than
25 ns is detected on any subsequent PD cycle.
The N-channel open-drain analog lock detect should be
operated with an external pull-up resistor of 10 kΩ nominal.
When lock has been detected, this output becomes high with
narrow, low going pulses.
03338-021
DGND
DV
DD
CONTROL
MUX
ANALOG LOCK DETECT
DIGITAL LOCK DETECT
R COUNTER OUTPUT
N COUNTER OUTPUT
SDOUT
MUXOUT
Figure 21. MUXOUT Circuit
INPUT SHIFT REGISTER
The ADF4107 digital section includes a 24-bit input shift
register, a 14-bit R counter, and a 19-bit N counter, comprising a
6-bit A counter and a 13-bit 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 diagram of Figure 2. The truth table for
these bits is shown in Table 5. Figure 22 shows a summary of
how the latches are programmed.
Table 5. C2, C1 Truth Table
Control Bits
Data Latch
C2 C1
0 0 R Counter
0 1 N Counter (A and B)
1 0 Function Latch (Including Prescaler)
1 1 Initialization Latch