Product Specification
PE97042
Page 10 of 12
2007-2010 Peregrine Semiconductor Corp. All rights reserved.
Document No. 70-0236-04
│ UltraCMOS RFIC Solutions
Figure 9. Serial Interface Mode Timing Diagram
t
DHLD
t
DSU
t
ClkH
t
ClkL
t
CWR
t
PW
t
WRC
t
EC
t
CE
E_WR
DATA
CLOCK
S_WR
and
PD_D results in a decrease in VCO frequency.
Software tools for designing the active loop filter can
be found at Peregrine’s web site: www.psemi.com
Lock Detect Output
A lock detect signal is provided at pin LD, via the pin
CEXT (see Figure 1). CEXT is the logical “NAND” of
PD_
and PD_D waveforms, driven through a series
2 k
resistor. Connecting C
EXT to an external shunt
capacitor provides integration of this signal.
The CEXT signal is then sent to the LD pin through an
internal inverting comparator with an open drain
output. Thus LD is an “AND” function of PD_
and
PD_
D.
Enhancement Register
The functions of the enhancement register bits are shown below. All bits are active high. Operation is
undefined if more than one output is sent to DOUT.
Table 9. Enhancement Register Bit Functionality
** Program to 0
Phase Detector Outputs
The phase detector is triggered by rising edges from
the main counter (fp) and the reference counter (fc).
It has two outputs,
PD_, and PD_D. If the divided
VCO leads the divided reference in phase or
frequency (fp leads fc), PD_D pulses “l(fā)ow”. If the
divided reference leads the divided VCO in phase or
frequency (fc leads fp), PD_ pulses “l(fā)ow”. The
width of either pulse is directly proportional to phase
offset between the two input signals, fp and fc. The
phase detector gain is 430 mV / radian.
PD_ and PD_D are designed to drive an active
loop filter which controls the VCO tune voltage.
PD_ pulses result in an increase in VCO frequency
Bit Function
Description
Bit 0
Reserved**
Bit 1
Reserved**
Bit 2
fp output
Drives the M counter output onto the DOUT output.
Bit 3
Power down
Power down of all functions except programming interface.
Bit 4
Counter load
Immediate and continuous load of counter programming.
Bit 5
MSEL output
Drives the internal dual modulus prescaler modulus select (MSEL) onto the DOUT output.
Bit 6
fc output
Drives the R counter output onto the DOUT output
Bit 7
PB
Allows Fin to bypass the 10/11 prescaler