Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsClock & Timing ICsTSSOP 8

General Description

The DS1181L 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

DS1181L 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, allowing direct EMI control and

optimization. In addition, through an enable pin the dither-

ing can be enabled or disabled for easy comparison of

system performance during EMI testing. This same input

pin also allows the DS1181L output to be three-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 DS1181L 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

DS1181L

20MHz to 134MHz Spread-Spectrum

Clock Modulator for LCD Panels

________________________________________________________________

Maxim Integrated Products

Rev 1; 8/08

Denotes a lead(Pb)-free/RoHS-compliant package.

T = Tape and reel.

Ordering Information

PART TEMP RANGE PIN-PACKAGE

DS1181LE+ -40°C to +125°C 8 TSSOP

DS1181LE+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

SSO

= 20MHz to

134MHz (DITHERED)

= 20MHz TO

134MHz

CRSEL

SSEN

ENABLE

LOGIC

DS1181L

SSO

GND

7 CRSELSMSEL1

SMSEL2

CLKIN

TSSOP

TOP VIEW

SSEN

DS1181L

Pin Configuration

For information on other Maxim products, visit Maxim’s website at www.maxim-ic.com.

Typical Operating Circuit appears at end of data sheet.

Summary of content (6 pages)

PAGE 1
Rev 1; 8/08 20MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels The DS1181L 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 DS1181L accepts an input clock signal in the range of 20MHz to 134MHz and delivers a spread-spectrum modulated output clock signal.
PAGE 2
DS1181L 20MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC Relative to GND ...............-0.5V to +4.3V Voltage Range on Any Lead Relative to GND ..................-0.5V to (VCC + 0.5V), not to exceed +4.3V Operating Temperature Range .........................-40°C to +125°C Storage Temperature Range .............................-55°C to +125°C Soldering Temperature...................
PAGE 3
20MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels SUPPLY CURRENT vs. SUPPLY VOLTAGE CLKIN = 134MHz 10 ICC (mA) CLKIN = 20MHz 4 CLKIN = 20MHz 6 CL = 7pF CL = 7pF 0 0 0 3.1 3.2 3.3 3.4 3.5 6 2 2 CL = 7pF 3.6 -40 10 60 20 110 40 60 80 100 120 TEMPERATURE (°C) FREQUENCY (MHz) DUTY CYCLE vs. SUPPLY VOLTAGE DUTY CYCLE vs. TEMPERATURE SPECTRUM ATTENUATION vs.
PAGE 4
20MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels DS1181L Pin Description PIN NAME 1 CLKIN 2 SMSEL1 FUNCTION Clock Input. 20MHz to 134MHz clock input (fIN). Spread-Spectrum Magnitude Select Inputs. These digital inputs select the desired spread-spectrum magnitude as shown in the table below. SMSEL2 SMSEL1 MAGNITUDE SELECTED (%) 0 0 ±2.0 0 1 1 0 ±1.5 ±1.0 1 1 ±0.5 3 SMSEL2 4 GND Ground 5 SSEN Spread-Spectrum Enable.
PAGE 5
20MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels Power-Supply Decoupling To achieve best results, it is highly recommended that a decoupling capacitor is used on the IC power-supply pins. Typical values of decoupling capacitors are 0.01µF and 0.1µF. Use a high-quality, ceramic, surface-mount capacitor, and mount it as close as possible to the VCC and GND pins of the IC to minimize lead inductance. IF SSEN = 1 fIN + (0.5%, 1.0%, 1.5%, OR 2.0% OF fIN) DITHER AMOUNT (±0.5%, ±1.0%, ±1.5%, OR ±2.
PAGE 6
DS1181L 20MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels Revision History REVISION NUMBER REVISION DATE 0 11/07 1 8/08 DESCRIPTION PAGES CHANGED Initial release. — Increased the absolute maximum ratings range from +3.63V to +4.3V. 2 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied.