pe3238 Peregrine Semiconductor Corp., pe3238 Datasheet - Page 11

• Manufacturer Part Number: pe3238
• Description: 1500 Mhz Ultracmos? Integer-n Pll For Low Phase Noise Applications
• Manufacturer: Peregrine Semiconductor Corp.

PE3238
Product Specification
Enhancement Register
The functions of the enhancement register bits are shown below in Table 9 with all bits active “high”.
Table 9. Enhancement Register Bit Functionality
Phase Detector
The phase detector is triggered by rising edges
from the main Counter (f
counter (f
and
reference in phase or frequency (f
D pulses “low”. If the divided reference leads the
divided VCO in phase or frequency (f
PD_D pulses “low”. The width of either pulse is
directly proportional to phase offset between the
two input signals, f
PD_U and PD_D drive an active loop filter which
controls the VCO tune voltage. PD_U pulses
result in an increase in VCO frequency and PD_D
results in a decrease in VCO frequency.
Document No. 70-0031-03 │ www.psemi.com
** Program to 0
Bit 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
PD_D. If the divided VCO leads the divided
Bit Function
c
). It has two outputs, namely PD_U,
Prescaler output
MSEL output
Counter load
Power down
Reserved**
Reserved**
Reserved**
f
p
, f
c
OE
p
and f
p
c
) and the reference
.
Power down of all functions except programming interface.
Immediate and continuous load of counter programming as directed by the Bmode and Smode inputs.
Drives the internal dual modulus prescaler modulus select (MSEL) onto the Dout output.
Drives the raw internal prescaler output onto the Dout output.
f
p
, f
c
outputs disabled.
p
leads f
c
leads f
c
), PD_
p
),
Description
A lock detect output, LD is also provided, via the
pin Cext. Cext is the logical “NAND” of PD_U and
PD_D waveforms, which is driven through a series
2 kΩ resistor. Connecting Cext to an external
shunt capacitor provides integration. Cext also
drives the input of an internal inverting comparator
with an open drain output. Thus LD is an “AND”
function of PD_U and PD_D.
©2003-2005 Peregrine Semiconductor Corp. All rights reserved.
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