LTC6900 Low Power, 1kHz to 20MHz Resistor Set SOT-23 Oscillator FEATURESDESCRIPTION n One External Resistor Sets the Frequency The LTC®6900 is a precision, low power oscillator that is n 1kHz to 20MHz Frequency Range easy to use and occupies very little PC board space. The n 500μA Typical Supply Current, VS = 3V, 3MHz oscillator frequency is programmed by a single external n Frequency Error ≤1.5% Max, 5kHz to 10MHz resistor (RSET). The LTC6900 has been designed for high (TA = 25°C) accuracy operation (≤1.5% frequency error) without the n Frequency Error ≤ 2% Max, 5kHz to 10MHz need for external trim components. (TA = 0°C to 70°C) The LTC6900 operates with a single 2.7V to 5.5V power n ±40ppm/°C Temperature Stability supply and provides a rail-to-rail, 50% duty cycle square n 0.04%/V Supply Stability wave output. The CMOS output driver ensures fast rise/fall n 50% ±1% Duty Cycle 1kHz to 2MHz times and rail-to-rail switching. The frequency-setting n 50% ± 5% Duty Cycle 2MHz to 10MHz resistor can vary from 10kΩ to 2MΩ to select a master n Fast Start-Up Time: 50μs to 1.5ms oscillator frequency between 100kHz and 20MHz (5V n 100Ω CMOS Output Driver supply). The three-state DIV input determines whether the n Operates from a Single 2.7V to 5.5V Supply master clock is divided by 1, 10 or 100 before driving the n Low Profi le (1mm) ThinSOT™ Package output, providing three frequency ranges spanning 1kHz to 20MHz (5V supply). The LTC6900 features a proprietary APPLICATIONS feedback loop that linearizes the relationship between RSET n and frequency, eliminating the need for tables to calculate Portable and Battery-Powered Equipment n frequency. The oscillator can be easily programmed using PDAs n the simple formula outlined below: Cell Phones n Low Cost Precision Oscillator 100 ⎧ , DIV Pin = V + n Charge Pump Driver ⎛ ⎞ ⎪ fOSC = 10MHz • 20k 10, ⎨ DIV Pin = Open n Switching Power Supply Clock Reference ⎝⎜ N•RSET ⎠⎟ , N= n Clocking Switched Capacitor Filters 1, ⎩⎪ DIV Pin = GND n Fixed Crystal Oscillator Replacement L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Ceramic Oscillator Replacement Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATIONRSET vs Desired Output Frequency 10000 Clock Generator 1kHz ≤ fOSC ≤ 20MHz 5V 1 5 1000 V+ OUT ÷100 ÷10 ÷1 0.1μF LTC6900 2 5V, N = 100 10k ≤ RSET ≤ 2M GND (kΩ) 100 3 4 SET SET DIV OPEN, N = 10 R N = 1 6900 TA01a 10 20k fOSC = 10MHz • ( ) N • RSET 1 1k 10k 100k 1M 10M 100M DESIRED OUTPUT FREQUENCY (Hz) 6900 TA01b 6900fa 1
