PRELIMINARY Specification
Alliance Semiconductor®
P1818/19/20/21/22
Low Power Mobile VGA EMI Reduction IC
FEATURES
•
•
•
FCC approved method of EMI attenuation
Provides up to 15 dB EMI reduction
Generates a low EMI spread spectrum clock
and a non-spread
Reference Clock
of the
input frequency
Optimized for frequency range from 10 MHz
to 170 MHz
P1818: 10 MHz to 20 MHz
P1819: 20 MHz to 40 MHz
P1820: 40 MHz to 80 MHz
P1821: 10 MHz to 40 MHz
P1822: 40 MHz to 170 MHz
•
•
•
•
•
Low inherent cycle-to-cycle jitter
8
spread % selections:
+/-0.625% to –3.5%
3.3V operating voltage
CMOS/TTL compatible inputs and outputs
Ultra low power
CMOS design
TBD mA @3.3V, 10 MHz
TBD mA @3.3V, 14 MHz
TBD mA @3.3V, 27MHz
•
•
•
•
•
Supports notebook VGA and other LCD timing
controller applications
Power Down
function for mobile application
Products are available for industrial
temperature range.
Available in 8 pin SOIC and TSSOP
•
•
Internal loop filter minimizes external
components and board space
Selectable spread options:
Down Spread
and
Center Spread
PRODUCT DESCRIPTION
The P18XX is a versatile spread spectrum
frequency modulator designed specifically for a
wide range of input clock frequencies from 10
MHz to 170 MHz (see Table 1.1). The P18XX can
generate an EMI reduced clock from crystal,
ceramic resonator, or system clock. The P18XX-A
to -H offers various combinations of spread
options and percentage deviations (see Table
1.2). These combinations include Down Spread,
Center Spread and percentage deviation range
from +/-0.625% to -3.50%.
The P18XX reduces electromagnetic interference
(EMI) at the clock source, allowing a system wide
EMI reduction for all the down stream clocks and
data dependent signals.
The P18XX allows
significant system cost savings by reducing the
number of circuit board layers, ferrite beads,
shielding, and other passive components that are
traditionally required to pass EMI regulations.
The P18XX modulates the output of a single PLL
in order to “spread” the bandwidth of a
synthesized clock, thereby decreasing the peak
amplitudes of its harmonics. This results in
significantly lower system EMI compared to the
typical narrow band signal produced by oscillators
and most clock generators. Lowering EMI by
increasing a signal’s bandwidth is called “spread
spectrum clock generation”.
The P18XX uses the most efficient and optimized
modulation profile approved by the FCC and is
implemented by using a proprietary all-digital
method.
APPLICATIONS
The P18XX is targeted towards EMI management
for memory and LVDS interfaces in mobile
graphic
chipsets
and
high-speed
digital
applications such as PC peripheral devices,
consumer electronics, and embedded controller
systems.
May, 2002
Revision C
PulseCore – A Division of Alliance Semiconductor
3160 De La Cruz Blvd., Suite 200 • Santa Clara • CA • 95054
Tel (408) 748-6988 • Fax (408) 748-0009
http://www.pulsecore.com
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PRELIMINARY Specification
Alliance Semiconductor®
PIN DESCRIPTION
Description
Connect to externally generated clock signal or crystal.
Ground Connection. Connect to system ground.
Spread Range Select. Digital logic input used to select frequency
deviation (see Table 2). This pin has an internal pull-up resistor.
3*
D_C
I
Digital logic input used to select Down (LOW) or Center (HIGH) Spread
Options (see Table 2). This pin has an internal pull-up resistor.
4
ModOut
O
Spread Spectrum clock output (see Table 1 and Table 2).
5
REF
O
Non-modulated reference output clock of the input frequency.
5/6* FRS
I
Frequency Range Select. Digital logic input used to select input
frequency range (see Table 1.1). This pin has an internal pull-up resistor.
6*
PD#
I
Power-Down control pin. Pull LOW to enable Power-Down mode. This
pin has an internal pull-up resistor.
7
VDD
P
Connect to +3.3V
8
XOUT
I
Connect to crystal. No connect if externally generated clock signal is
used.
8*
MRS
I
Modulation Rate Select. Digital logic input used to select Modulation Rate
(see Table 2). This pin has an internal pull-up resistor.
*Please refer to Figure 1 for pin assignment
PIN #
1
2
3
Name
XIN
VSS
SRS
Type
I
P
I
P1818/19/20/21/22
May, 2002
Revision C
PulseCore – A Division of Alliance Semiconductor
3160 De La Cruz Blvd., Suite 200 • Santa Clara • CA • 95054
Tel (408) 748-6988 • Fax (408) 748-0009
http://www.pulsecore.com
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PRELIMINARY Specification
Alliance Semiconductor®
EMC SOFTWARE SIMULATION
By using PulseCore’s proprietary EMC simulation software –
EMI-lator
®
, radiated system level EMI analysis
can be made easier, allowing a quantitative measure on the benefits of PulseCore’s EMI reduction products.
The simulation engine of this EMC software has already been characterized to correlate with the electrical
characteristics of PulseCore EMI reduction IC’s.
Figure 3
below is an example of the simulation result.
Please visit our web site at
www.pulsecore.com
for information on how to obtain a free copy and
demonstration of
EMI-lator
®
.
Figure 3 - Simulation Results from
EMI-Lator®
P1818/19/20/21/22
May, 2002
Revision C
PulseCore – A Division of Alliance Semiconductor
3160 De La Cruz Blvd., Suite 200 • Santa Clara • CA • 95054
Tel (408) 748-6988 • Fax (408) 748-0009
http://www.pulsecore.com
5 of 5
Analogue and Mixed Signal
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