Rainbow Electronics DS1081L - Manual

General Description
The DS1081L is a spread-spectrum clock modulator IC
that reduces EMI in high clock-frequency-based, digital
electronic equipment.
Using an integrated phase-locked loop (PLL), the
DS1081L accepts an input clock signal in the range of
20MHz to 134MHz and delivers a spread-spectrum mod-
ulated output clock signal. The PLL modulates, or dithers,
the output clock about the center input frequency at a
pin-selectable magnitude and dither rate, allowing direct
EMI control and optimization. In addition, through an
enable pin the dithering can be enabled or disabled for
easy comparison of system performance during EMI test-
ing. This same input pin also allows the DS1081L output
to be tri-stated.
By dithering the system clock, all the address, data,
and timing signals generated from this signal are also
dithered so that the measured EMI at the fundamental
and harmonic frequencies is greatly reduced. This is
accomplished without changing clock rise/fall times or
adding the space, weight, design time, and cost asso-
ciated with mechanical shielding.
The DS1081L is provided in an 8-pin TSSOP package
and operates over a full automotive temperature range
of -40°C to +125°C.
Applications
LCD Panels for TVs, Desktop Monitors, and
Notebook and Tablet PCs
Automotive Telematics and Infotainment
Printers
Features
♦ Modulates a 20MHz to 134MHz Clock with Center
Spread-Spectrum Dithering
♦ Selectable Spread-Spectrum Modulation
Magnitudes of:
±0.5%
±1.0%
±1.5%
±2.0%
♦ Low 75ps Cycle-to-Cycle Jitter
♦ Spread-Spectrum Disable Mode
♦ Pin Compatible with Alliance/PulseCore
Semiconductor P2040 Series Devices
♦ Clock Output Disable
♦ Low Cost
♦ Low Power Consumption
♦ 3.3V Single Voltage Supply
♦ -40°C to +125°C Temperature Range
♦ Small 8-Pin TSSOP Package
DS1081L
20MHz to 134MHz Spread-Spectrum
Clock Modulator for LCD Panels
______________________________________________ Maxim Integrated Products 1
Rev 0; 4/07
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
+ Denotes lead-free package.
T Denotes tape-and-reel.
Ordering Information
PART TEMP RANGE PIN-PACKAGE
DS1081LE+ -40°C to +125°C 8 TSSOP
DS1081LE+T -40°C to +125°C 8 TSSOP
Block Diagram
GND
SSO PLL WITH CENTER-
DITHERED
SPREAD
SPECTRUM
CONFIGURATION
DECODE AND
CONTROL
SMSEL1
CLKIN
SMSEL2
f SSO = 20MHz to
134MHz (DITHERED)
V CC
V CC
f IN = 20MHz TO
134MHz
DS1081L
CRSEL
SSEN ENABLE
LOGIC
Pin Configuration and Typical Operating Circuit appear at
end of data sheet.
SSO
GND
1
2
8
7 CRSEL SMSEL1
SMSEL2
CLKIN
TSSOP
(4.40mm)
TOP VIEW
3
4
6
5
DS1081L
V CC
SSEN
Pin Configuration