PE3238
Product Specification
Functional Description
The PE3238 consists of a prescaler, counters, a
phase detector and control logic. The dual
modulus prescaler divides the VCO frequency by
either 10 or 11, depending on the value of the
modulus select. Counters “R” and “M” divide the
reference and prescaler output, respectively, by
integer values stored in a 20-bit register. An
additional counter (“A”) is used in the modulus
select logic. The phase-frequency detector
generates up and down frequency control signals.
The control logic includes a selectable chip
interface. Data can be written via serial bus,
parallel bus, or hardwired direct to the pins. There
are also various operational and test modes and
lock detect.
Figure 4. Functional Block Diagram
f
r
R Counter
(6-bit)
f
c
D(7:0)
Sdata
Control
Pins
Control
Logic
R(5:0)
M(8:0)
A(3:0)
Phas
e
Detector
PD_U
PD_D
LD
Cext
Modulus
Select
F
in
F
in
10/11
Prescaler
M Counter
(9-bit)
f
p
Document No. 70-0031-03
│
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©2003-2005 Peregrine Semiconductor Corp. All rights reserved.
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