Product Specification
PE3342
Page 6 of 17
©2005-8 Peregrine Semiconductor Corp. All rights reserved. Document No. 70-0091-04 │UltraCMOS™ RFIC Solutions
Functional Description
The PE 33 42 c o ns is ts of a du al mo dul us pr es caler,
three programmable counters, a phase detector
and control logic with EEPROM memory (see
Figure 1).
The dual modulus prescaler divides the VCO
frequency by either 10 or 11, depending on the
state of the internal modulus se lect logic. The R
and M counters divide the reference and prescaler
outputs by integer values stored in one of three
selectable registers. The modulus select logic
uses th e 4- bi t A coun ter .
The ph as e- freque nc y detect or gen er ates up and
down frequency control signals and are also used
to enable a lock detect circuit.
Frequency control data is loaded into the device
via the Serial Data Port, and can be placed in
three separate frequency registers. One of these
registers (EE register) is used to load from and
write to the non-volatile 20-bit EEPROM.
Various operational and test modes are available
through the enhancement register, which is only
accessible through th e Serial Data Port (it cannot
be loaded from the EEPROM).
Main Counter Chain
The main counter chain divides the RF input
frequency, Fin, by an integer derived from the
user-defined values in the M and A counters. It
operates in two modes:
High Frequency Mode
Setting PB (prescaler bypass) LOW enables the
÷10 /1 1 pr esc aler, pr ovi di n g op er ation to 2. 7 GHz .
In this mode, the output from the main counter
chain, fp, is related to the VCO frequency, Fin, by
the following equation:
fp = Fin / [10 x (M + 1) + A] (1)
wh ere 0
≤
A
≤
15 and A
≤
M + 1; 1
≤
M
≤
511
When the loop is locked, Fin is related to the
reference freque nc y, fr, by the following equation:
Fin = [10 x (M + 1) + A] x (fr / (R+1)) (2)
wh ere 0
≤
A
≤
15 and A
≤
M + 1; 1
≤
M
≤
511
A consequence of the uppe r lim it on A is th at F in
must be greater th an or equ al to 90 x (fr / (R+1)) t o
obtain contiguous channels. Programming the M
counter with the min imum value of 1 will result in a
minimum M counter divide ratio of 2.
Programming the M and A counters with their
maximum values provides a divide ratio of 5135.
Prescaler Bypass Mode
Setti ng the PB bi t of a fr eq ue ncy re gis ter HIGH
allo ws F in to bypass the ÷10/11 prescaler. In this
mode , t he pr escaler and A co un ter ar e powered
down, and the input VCO frequency is divided by
the M counter directly. The following equation
relate s Fin to the reference freq uency fr:
Fin = (M + 1) x (fr / (R+1)) (3)
wh ere 1 ≤ M ≤ 511
Refe rence Counter
The reference counter chain divides the reference
freq ue nc y, fr, do wn to the phase detector
compar i son freq ue nc y, fc.
The output frequency of the 6-bit R Co unter is
related to the reference frequency by the following
equation:
fc = fr / (R + 1) (4)
where 0
≤
R
≤
63
Not e that programming R with 0 will pass the
reference freque nc y, fr, directly to the phase
detector.
Phase Detector
The phase detector is triggered by rising edge s
from the main counter (fp) and the reference
co unte r (fc). It has two outputs, PD_U, and PD_D.
If the divided VCO leads the divided reference in
phase or frequency (fp leads fc), PD_D p ul ses
LOW. If the divided reference leads the divided
VCO in phase or frequency (fc leads fp), PD_U
pulses LOW. The width of either pulse is directly
prop or ti o nal to th e phas e offset betw e en th e fp an d
fc signals.