Rev 0; 5/07 16MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels The DS1083L 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 DS1083L accepts an input clock signal in the range of 16MHz to 134MHz and delivers a spread-spectrum modulated output clock signal. The PLL modulates, or dithers, the output clock about the center input frequency at a pin-selectable magnitude. The DS1083L automatically adjusts the dither rate based on the input clock frequency to maximize the EMI reduction. 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 associated with mechanical shielding. The DS1083L is provided in a low-cost, space-saving, 6-lead thin SOT23 package and operates over a full automotive temperature range of -40°C to +125°C. Features ♦ Modulates a 16MHz to 134MHz Clock with Center Spread-Spectrum Dithering ♦ Selectable Spread-Spectrum Modulation Magnitudes of: ±0.5% ±1% ±1.5% ±2% ♦ Low 75ps Cycle-to-Cycle Jitter ♦ Automatic Dither Cycle Rate Adjustment to Maximize EMI Reduction ♦ Low Cost ♦ Low Power Consumption ♦ 3.3V Single Voltage Supply ♦ -40°C to +125°C Operating Temperature Range ♦ Small 6-Lead Thin SOT23 Package Applications LCD Panels for TVs, Desktop Monitors, Notebook and Tablet PCs Automotive Telematics and Infotainment Ordering Information PART TEMP RANGE DS1083LR+T -40°C to +125°C PIN-PACKAGE 6 Thin SOT23 +Denotes a lead-free package. T = Tape and reel. Printers Pin Configuration and Typical Operating Circuit appear at end of data sheet. Block Diagram DS1083L CLKIN fIN = 16MHz TO 134MHz SSO PLL WITH CENTERSPREAD DITHERING VCC fSSO = 16MHz to 134MHz (DITHERED) VCC VCC RPU RPU SMSEL1 CLOCK RATE DETECT CONFIGURATION DECODE AND CONTROL GND SMSEL2 ________________________________________________________________ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. 1 DS1083L General Description DS1083L 16MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels ABSOLUTE MAXIMUM RATINGS Voltage Range on VCC Relative to GND.............-0.5V to +3.63V Voltage Range on Any Lead Relative to GND ................-0.5V to (VCC + 0.5V), not to exceed +3.63V Operating Temperature Range .........................-40°C to +125°C Storage Temperature Range .............................-55°C to +125°C Soldering Temperature...........................Refer to the IPC/JEDEC J-STD-020 Specification. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED OPERATING CONDITIONS (TA = -40°C to +125°C, unless otherwise noted.) PARAMETER SYMBOL MAX UNITS 3.0 3.6 V VIH 0.7 x VCC VCC + 0.3 V SMSEL1/SMSEL2 Input Logic 0 VIL -0.3 0.3 x VCC V SSO Load CL VCC Supply Voltage VCC SMSEL1/SMSEL2 Input Logic 1 CONDITIONS (Note 1) MIN TYP f SSO < 80MHz 15 80MHz f SSO < 134MHz 7 pF CLKIN Frequency f IN 16 134 MHz CLKIN Duty Cycle f INDC 40 60 % VCC Power-Up Time t PV 200 ms MAX UNITS 15 mA GND to VCCMIN DC ELECTRICAL CHARACTERISTICS (VCC = +3.0V to +3.6V, TA = -40°C to +125°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS Supply Current ICC CL = 7pF, f IN = 134MHz SMSEL1/SMSEL2 Pullup Resistance RPU TA = +25°C SMSEL1/SMSEL2 Input Leakage I IL MIN 60 Low-Level Output Voltage (SSO) VOL 0V < VIN < VCC I OL = 4mA High-Level Output Voltage (SSO) VOH I OH = -4mA TYP 100 140 k ±80 μA 0.4 V 2.4 V AC ELECTRICAL CHARACTERISTICS (VCC = +3.0V to +3.6V, TA = -40°C to +125°C, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS SSO Duty Cycle f SSODC Measured at VCC/2 SSO Rise Time tR CL = 7pF SSO Fall Time tF Peak Cycle-to-Cycle Jitter tJ MIN TYP 40 60 UNITS % 1 ns CL = 7pF 1 ns TA = -40°C to +85°C, 10,000 cycles 75 ps Note 1: All voltages referenced to ground. Currents into the IC are positive and currents out of the IC are negative. 2 MAX _______________________________________________________________________________________ 16MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels CLKIN = 16MHz 4 2 3.1 3.2 3.3 3.4 3.5 4 3.6 VCC = 3.6V 8 VCC = 3.0V 6 4 2 0 -40 -20 0 20 40 60 80 16 100 120 36 56 76 96 134 116 FREQUENCY (MHz) DUTY CYCLE vs. TEMPERATURE DUTY CYCLE vs. SUPPLY VOLTAGE SPECTRUM ATTENUATION vs. FREQUENCY AT DIFFERENT DITHER AMPLITUDES 60 DS1083L toc04 56 DUTY CYCLE (%) 54 52 50 48 54 52 50 48 46 46 44 44 42 42 40 CLKIN = 66MHz 58 ±1% 0.5% ±1.5% ±2% fOUT = 40MHz 3dB ATTENUATION (dB) CLKIN = 66MHz DS1083L toc06 TEMPERATURE (°C) DS1083L toc05 SUPPLY VOLTAGE (V) 56 DUTY CYCLE (%) CLKIN = 16MHz 0 3.0 58 8 6 10 2 0 60 CLKIN = 66MHz SUPPLY CURRENT (mA) 8 6 CLKIN = 134MHz 10 SUPPLY CURRENT (mA) SUPPLY CURRENT (mA) CLKIN = 66MHz 12 DS1083L toc02 DS1083L toc01 CLKIN = 134MHz 10 SUPPLY CURRENT vs. FREQUENCY SUPPLY CURRENT vs. TEMPERATURE 12 DS1083L toc03 SUPPLY CURRENT vs. SUPPLY VOLTAGE 12 6dB 4.5dB fOUT = 40MHz RBW = 120kHz CENTER DITHER 40 -40 -20 0 20 40 60 TEMPERATURE (°C) 80 100 120 3.0 3.1 3.2 3.3 3.4 SUPPLY VOLTAGE (V) 3.5 3.6 FREQUENCY (MHz) _______________________________________________________________________________________ 3 DS1083L Typical Operating Characteristics (TA = +25°C, unless otherwise noted.) 16MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels DS1083L Pin Description PIN NAME DESCRIPTION 1 CLKIN 2 GND Ground SSO Spread-Spectrum Clock Output. Outputs a center-dithered spread-spectrum version of the clock input at CLKIN. 3 4 SMSEL2 5 SMSEL1 6 VCC Clock Input. 16MHz 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. Both inputs contain pullup resistors (RPU) to VCC. SMSEL2 0 SMSEL1 0 MAGNITUDE SELECTED (%) ±2 0 1 ±1.5 1 0 ±1 1 1 ±0.5 Supply Voltage Detailed Description The DS1083L modulates an input clock to provide a center-dithered spread-spectrum output. A 16MHz to 134MHz clock is applied to the CLKIN pin. The PLL dithers the output clock about its center frequency at a user-selectable magnitude. The user is required to cycle power to the device each time there is a change in the input frequency, for the PLL to lock correctly. This ensures proper output frequency and dither rate. The desired spread-spectrum magnitude is selected using input pins SMSEL1 and SMSEL2 (see the Pin Description for details). The DS1083L is capable of generating spread-spectrum clocks from 16MHz to 134MHz. Applications Information 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, surfacemount capacitor, and mount it as close as possible to the VCC and GND pins of the IC to minimize lead inductance. Chip Information SUBSTRATE CONNECTED TO GROUND Dither-Rate Selection The output spread-spectrum dither rate is automatically adjusted depending on the input frequency, to maximize EMI reduction. The dither cycle rate is: fIN/512, if fIN is between 16MHz and 33MHz fIN/1024, if fIN is between 33MHz and 64MHz fIN/2048, if fIN is between 64MHz and 134MHz On power-up, the output clock (SSO) remains threestated until it reaches a stable frequency (fSSO). The dither rate is selected by sampling the input clock at power-up. 4 _______________________________________________________________________________________ 16MHz to 134MHz Spread-Spectrum Clock Modulator for LCD Panels DS1083L IF DITHER AMOUNT = 0% fIN + (0.5%, 1%, 1.5%, OR 2% OF fIN) DITHER AMOUNT (±0.5%, ±1%, ±1.5%, OR ±2%) fIN fIN - (0.5%, 1%, 1.5%, OR 2% OF fIN) 1 fSSO DITHER CYCLE RATE* TIME *DITHER CYCLE RATE = fIN/512, IF fIN = 16MHz TO 33MHz fIN/1024, IF fIN = 33MHz TO 64MHz fIN/2048, IF fIN = 64MHz TO 134MHz Figure 1. Spread-Spectrum Frequency Modulation Typical Operating Circuit VCC fIN = 16MHz TO 134MHz CLKIN GND fSSO SSO VCC DS1083L SMSEL1 DECOUPLING CAPACITOR SMSEL2 DITHERED NOTE: IN THE ABOVE CONFIGURATION WITH SMSEL1 CONNECTED TO VCC AND SMSEL2 CONNECTED TO GND, THE DEVICE WILL HAVE A SPREAD-SPECTRUM MAGNITUDE OF ±1.5%. Package Information Pin Configuration For the latest package outline information, go to www.maxim-ic.com/packages. TOP VIEW + CLKIN 1 GND 2 DS1083L SSO 3 6 VCC 5 SMSEL1 4 SMSEL2 PACKAGE TYPE DOCUMENT NO. 6 Thin SOT23 21-0114 THIN SOT23 Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 5 © 2007 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.