LTC6902 Datasheet

• 2-, 3- or 4-Phase Outputs
• Optional Spread Spectrum Frequency Modulation for Improved EMC Performance
• 5kHz to 20MHz Frequency Range
• One External Resistor Sets the Frequency
• One External Resistor Sets Percent Frequency Spreading
• 400µA Typical Supply Current, V_S = 3V, 1MHz
• Frequency Error < 1.5% Max, 5kHz to 10MHz (T_A = 25°C)
• Frequency Error < 2% Max, 5kHz to 10MHz (T_A = 0°C to 70°C)
• ±40ppm/°C Temperature Stability
• Fast Start-Up Time: 50µs to 1.5ms
• 100Ω CMOS Output Driver
• Operates from a Single 2.7V to 5.5V Supply
• Available in 10-Lead MS Package

• Switching Power Supply Clock Reference
• Portable and Battery-Powered Equipment
• PDAs
• Cell Phones
• Clocking Switched Capacitor Filters

The LTC6902 is a precision, low power and easy-to-use oscillator that provides multiphase outputs in a small package. The oscillator frequency is set by a single external resistor (R_SET). The LTC6902 also provides an optional spread spectrum frequency modulation (SSFM) capability that can be activated and controlled by an additional external resistor (R_MOD).

The LTC6902's master oscillator is controlled by the R_SET resistor and has a range of 100kHz and 20MHz. In order to accommodate a wider output frequency range, a programmable divider (divide by 1, 10 or 100) is included. The integrated programmable multiphase circuit provides either 2-, 3- or 4-phase waveforms.

The LTC6902's SSFM capability modulates the oscillator's frequency by a pseudorandom noise (PRN) signal to spread the oscillator's energy over a wide frequency band. This spreading decreases the peak electromagnetic radiation level and improves electromagnetic compatibility (EMC) performance. The amount of frequency spreading is programmable by a single additional external resistor (R_MOD) and is disabled by grounding the MOD pin.