REV. A
ADF4210/ADF4211/ADF4212/ADF4213
–16–
PROGRAM MODES
Table III and Table V show how to set up the Program Modes
in the ADF421x family. The following should be noted:
1. IF and RF Analog Lock Detect indicate when the PLL is in
lock. When the loop is locked and either IF or RF Analog
Lock Detect is selected, the MUXOUT pin will show a logic
high with narrow low-going pulses. When the IF/RF Analog
Lock Detect is chosen, the locked condition is indicated only
when both IF and RF loops are locked.
2. The IF Counter Reset mode resets the R and AB counters in
the IF section and also puts the IF charge pump into three-
state. The RF Counter Reset mode resets the R and AB
counters in the RF section and also puts the RF charge
pump into three-state. The IF and RF Counter Reset mode
does both of the above. Upon removal of the reset bits, the
AB counter resumes counting in close alignment with the R
counter (maximum error is one prescaler output cycle).
3. The Fastlock mode uses MUXOUT to switch a second loop
filter damping resistor to ground during Fastlock operation.
Activation of Fastlock occurs whenever RF CP Gain in the
RF Reference counter is set to one.
IF Power-Down
It is possible to program the ADF421x family for either synchro-
nous or asynchronous power-down on either the IF or RF side.
Synchronous IF Power-Down
Programming a “1” to P7 of the ADF421x family will initiate a
power-down. If P2 of the ADF421x family has been set to “0”
(normal operation), a synchronous power-down is conducted.
The device will automatically put the charge pump into three-
state and then complete the power-down.
Asynchronous IF Power-Down
If P2 of the ADF421x family has been set to “1” (three-state the
IF charge pump), and P7 is subsequently set to “1,” an asyn-
chronous power-down is conducted. The device will go into
power-down on the rising edge of LE, which latches the “1” to
the IF power-down bit (P7).
Synchronous RF Power-Down
Programming a “1” to P16 of the ADF421x family will initiate a
power-down. If P10 of the ADF421x family has been set to “0”
(normal operation), a synchronous power-down is conducted. The
device will automatically put the charge pump into three-state
and then complete the power-down.
Asynchronous RF Power-Down
If P10 of the ADF421x family has been set to “1” (three-state
the RF charge pump), and P16 is subsequently set to “1,” an
asynchronous power-down is conducted. The device will go into
power down on the rising edge of LE, which latches the “1” to
the RF power-down bit (P16).
Activation of either synchronous or asynchronous power-down
forces the IF/RF loop’s R and AB dividers to their load state
conditions and the IF/RF input section is debiased to a high-
impedance state.
The REF
IN
oscillator circuit is only disabled if both the IF and
RF power-downs are set.
The input register and latches remain active and are capable of
loading and latching data during all the power-down modes.
The IF/RF section of the devices will return to normal powered
up operation immediately upon LE latching a “0” to the
appropriate power-down bit.
IF SECTION
PROGRAMMABLE IF REFERENCE (R) COUNTER
If control bits C2, C1 are 0, 0, the data is transferred from the
input shift register to the 14-bit IFR counter. Table III shows
the input shift register data format for the IFR counter and the
divide ratios possible.
IF Phase Detector Polarity
P1 sets the IF Phase Detector Polarity. When the IF VCO char-
acteristics are positive this should be set to “1.” When they are
negative it should be set to “0.” See Table III.
IF Charge Pump Three-State
P2 puts the IF charge pump into three-state mode when pro-
grammed to a “1.” It should be set to “0” for normal operation.
See Table III.
IF PROGRAM MODES
Table III and Table V show how to set up the Program Modes
in the ADF421x family.
IF Charge Pump Currents
IFCP2, IFCP1, IFCP0 program current setting for the IF
charge pump. See Table III.
PROGRAMMABLE IF AB COUNTER
If control bits C2, C1 are 0, 1, the data in the input register is used
to program the IF AB counter. The N counter consists of a 6-bit
swallow counter (A counter) and 12-bit programmable counter
(B counter). Table IV shows the input register data format for
programming the IF AB counter and the possible divide ratios.
IF Prescaler Value
P5 and P6 in the IF A, B Counter Latch sets the IF prescaler
value. See Table IV.
IF Power-Down
Table III and Table V show the power-down bits in the
ADF421x family.
IF Fastlock
The IF CP Gain bit (P8) of the IF N register in the ADF421x
family is the Fastlock Enable Bit. Only when this is “1” is IF
Fastlock enabled. When Fastlock is enabled, the IF CP current
is set to its maximum value. Since the IF CP Gain bit is con-
tained in the IF N Counter, only one write is needed to both
program a new output frequency and also initiate Fastlock. To
come out of Fastlock, the IF CP Gain bit on the IF N register
must be set to “0.” See Table IV.
RF SECTION
PROGRAMMABLE RF REFERENCE (R) COUNTER
If control bits C2, C1 are 1, 0, the data is transferred from the
input shift register to the 14-bit RFR counter. Table V shows
the input shift register data format for the RFR counter and the
possible divide ratios.
RF Phase Detector Polarity
P9 sets the IF Phase Detector Polarity. When the RF VCO
characteristics are positive this should be set to “1.” When they
are negative it should be set to “0.” See Table V.
RF Charge Pump Three-State
P10 puts the RF charge pump into three-state mode when pro-
grammed to a “1.” It should be set to “0” for normal operation.
See Table V.
