LTC6908 2-Output Precision Oscillator

Analog Devices LTC6908 is a 2-output precision oscillator shifted by either 180° or 90°. The oscillator frequency is programmed by a single external resistor (R_SET) and spread spectrum frequency modulation (SSFM) can be activated for improved electromagnetic compatibility (EMC) performance.

The LTC6908 operates with a single 2.7 V to 5.5 V supply and provides rail-to-rail, 50% duty cycle square-wave outputs. A single resistor from 10 k to 2 M is used to select an oscillator frequency from 50 kHz to 10 MHz (5 V supply). The oscillator can be easily programmed using the simple formula:
f_OUT = 10 MHz • 10 k/R_SET.

The LTC6908’s SSFM capability modulates the output frequency by a pseudorandom noise (PRN) signal to decrease the peak electromagnetic radiation level and improve EMC performance. The amount of frequency spreading is fixed at ±10% of the center frequency. When SSFM is enabled, the rate of modulation is selected by the user. The three possible modulation rates are f_OUT/16, f_OUT/32 and f_OUT/64. The LTC6908 is ideal for switching power supplies, battery equipment, and charge pump drivers.

Features
LTC6908-1: complementary outputs (0°/180°) LTC6908-2: quadrature outputs (0°/90°) 50 kHz to 10 MHz frequency range One external resistor sets the frequency Optional spread spectrum frequency modulation for improved EMC performance ±10% frequency spreading 400 µA supply current typical (V+ = 5 V, 50 kHz)		Frequency error ≤1.5% max. (TA = 25°C, V+ = 3 V) ±40 ppm/°C temperature stability Fast start-up time: 260 µs typical (1 MHz) Outputs muted until stable Operates from a single 2.7 V to 5.5 V supply Available in ThinSOT and DFN packages
Applications
Switching power supply clock reference Portable and battery-powered equipment		Precision programmable oscillator Charge pump driver