LTC6902 Multiphase Oscillator with Spread Spectrum Frequency Modulation FEATURES DESCRIPTIO n 2-, 3- or 4-Phase Outputs The LTC 6902 is a precision, low power and easy-to-use n Optional Spread Spectrum Frequency Modulation oscillator that provides multiphase outputs in a small for Improved EMC Performance package. The oscillator frequency is set by a single exter- n 5kHz to 20MHz Frequency Range nal resistor (R ). The LTC6902 also provides an optional SET n One External Resistor Sets the Frequency spread spectrum frequency modulation (SSFM) capability n One External Resistor Sets Percent Frequency that can be activated and controlled by an additional Spreading external resistor (R ). MOD n 400m A Typical Supply Current, V = 3V, 1MHz S The LTC6902s master oscillator is controlled by the R SET n Frequency Error 1.5% Max, 5kHz to 10MHz resistor and has a range of 100kHz and 20MHz. In order (T = 25 C) A to accommodate a wider output frequency range, a pro- n Frequency Error 2% Max, 5kHz to 10MHz grammable divider (divide by 1, 10 or 100) is included. (T = 0 C to 70 C) A The integrated programmable multiphase circuit pro- n 40ppm/ C Temperature Stability vides either 2-, 3- or 4-phase waveforms. n Fast Start-Up Time: 50m s to 1.5ms n The LTC6902s SSFM capability modulates the oscillators 100W CMOS Output Driver n frequency by a pseudorandom noise (PRN) signal to Operates from a Single 2.7V to 5.5V Supply n spread the oscillators energy over a wide frequency band. Available in 10-Lead MS Package This spreading decreases the peak electromagnetic radia- U tion level and improves electromagnetic compatibility APPLICATIO S (EMC) performance. The amount of frequency spreading n Switching Power Supply Clock Reference is programmable by a single additional external resistor n Portable and Battery-Powered Equipment (R ) and is disabled by grounding the MOD pin. MOD n PDAs , LTC and LT are registered trademarks of Linear Technology Corporation. n Cell Phones n Clocking Switched Capacitor Filters TYPICAL APPLICATIO Output Frequency Spectrum With and Without SSFM 0 500kHz, 4-Phase Clock with 20% Frequency Spreading OUTPUT SPECTRUM 5V WITH SSFM R 10k 20 MOD 0.1F DISABLED OUTPUT R 10k SET SPECTRUM 40 WITH 20% LTC6902 SPREADING + V SET 60 OPEN DIV MOD PH GND 80 OUT4 OUT1 OUT4 OUT3 OUT2 OUT3 OUT2 100 400 450 500 550 600 OUT1 6902 TA01 FREQUENCY (kHz) 6902 TA02 6902f 1 RELATIVE AMPLITUDE (dBm) U ULTC6902 UUW ABSOLUTE AXI U RATI GS PACKAGE/ORDER I FOR ATIO (Note 1) + Supply Voltage (V ) to GND ........................0.3V to 6V ORDER Voltage On Any Pin PART NUMBER TOP VIEW + + (Referred to GND) ......................... 0.3V to (V + 0.3V) V 1 10 SET LTC6902CMS DIV 2 9 MOD Operating Temperature Range (Note 9) PH 3 8 GND LTC6902IMS OUT1 4 7 OUT4 LTC6902C .......................................... 40 C to 85 C OUT2 5 6 OUT3 LTC6902I............................................ 40 C to 85 C MS PACKAGE MS PART MARKING 10-LEAD PLASTIC MSOP Specified Temperature Range (Note 10) T = 150 C, q = 250 C/W JMAX JA LTK2 LTC6902C .......................................... 40 C to 85 C LTK3 LTC6902I............................................ 40 C to 85 C Storage Temperature Range ................. 65 C to 150 C Consult LTC Marketing for parts specified with wider operating temperature ranges. Lead Temperature (Soldering, 10 sec).................. 300 C ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating + temperature range, otherwise specifications are at T = 25 C. V = 2.7V to 5.5V, R = 5k, C = 5pF, Pin 3 (PH) = 0V (2-phase, M = 1) A L L unless otherwise specified. Pin 9 (MOD) is at 0V unless otherwise specified. R is defined as a resistor connected from the SET pin SET + + to the V pin. R is defined as a resistor connected from the MOD pin to the V pin. MOD SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS + D f Frequency Accuracy (Notes 2, 3) V = 5V 5kHz f 10MHz 0.5 1.5 % OUT OUT 1kHz f 5kHz 2.0 % OUT 10MHz f 20MHz l 3.0 4.0 % OUT 5kHz f 10MHz, LTC6902C l 2.0 % OUT 5kHz < f 10MHz, LTC6902I l 2.5 % OUT + V = 2.7V 5kHz f 10MHz 0.5 1.5 % OUT 1kHz f 5kHz 2.0 % OUT 5kHz f 10MHz, LTC6902C l 2.0 % OUT 10MHz, LTC6902I l 2.5 % 5kHz f OUT + R Frequency Setting Resistor Range D f < 1.5%, V = 5V l 20 400 kW SET OUT + D f < 1.5%, V = 2.7V l 20 400 kW OUT D f /D T Frequency Drift Over Temperature R = 63.2k l 0.004 %/ C OUT SET (Note 3) + D f /D V Frequency Drift Over Supply (Note 3) V = 2.7V to 5V, R = 63.2k l 0.04 0.12 %/V OUT SET Timing Jitter (Note 4) 20k R 400k SET + Pin 2 = V (N = 100) 0.1 % Pin 2 = Open (N = 10) 0.2 % Pin 2 = 0V (N = 1) 0.6 % Long-Term Stability of 300 ppm/ kHr Output Frequency + Duty Cycle (Note 5) Pin 2 = V or Open (N = 100 or 10) Pin 3 = 0V (2-Phase, M = 1) l 49.0 50.0 51.0 % Pin 3 = Open (3-Phase, M = 3) l 32.3 33.3 34.3 % + Pin 3 = V (4-Phase, M = 4) l 49.0 50.0 51.0 % Pin 2 = 0V (N = 1) Pin 3 = 0V (2-Phase, M = 1) l 45.0 50.0 55.0 % Pin 3 = Open (3-Phase, M = 3) l 32.3 33.3 34.3 % + Pin 3 = V (4-Phase, M = 4) l 49.0 50.0 51.0 % 6902f 2 U WWW