Analog Devices LTC6990

Description

The LTC®6990 is a precision silicon oscillator with a programmablefrequency range of 488Hz to 2MHz. It can beused as a fixed-frequency or voltage-controlled oscillator(VCO). The LTC6990 is part of the TimerBlox® family ofversatile silicon timing devices.A single resistor, RSET, programs the LTC6990’s internalmaster oscillator frequency. The output frequency is determinedby this master oscillator and an internal frequencydivider, NDIV, programmable to eight settings from 1 to 128.fOUT =1MHzNDIV•50kΩRSET,NDIV = 1, 2, 4 …128Optionally, a second resistor at the SET input provideslinear voltage control of the output frequency and can beused for frequency modulation. A narrow or wide VCOtuning range can be configured by the appropriate selectionof the two resistors.The LTC6990 includes an enable function that is synchronizedwith the master oscillator to ensure clean, glitch-freeoutput pulses. The disabled output can be configured tobe high impedance or forced low.

Features

Fixed-Frequency or Voltage-Controlled Operation– Fixed: Single Resistor Programs Frequencywith <1.5% Max Error– VCO: Two Resistors Set VCO CenterFrequency and Tuning Rangen Frequency Range: 488Hz to 2MHzn 2.25V to 5.5V Single Supply Operationn 72μA Supply Current at 100kHzn 500μs Start-Up Timen VCO Bandwidth >300kHz at 1MHzn CMOS Logic Output Sources/Sinks 20mAn 50% Duty Cycle Square Wave Outputn Output Enable (Selectable Low or Hi-Z When Disabled)n –55°C to 125°C Operating Temperature Rangen Available in Low Profile (1mm) SOT-23 (ThinSOT™)and 2mm × 3mm DFN Package

Typical applications

• Voltage-Controlled Oscillator
• Low Cost Precision Programmable Oscillator
• High Vibration, High Acceleration Environments
• Replacement for Fixed Crystal and Ceramic Oscillators
• Portable and Battery-Powered Equipment

More information

• Datasheet
• IC product information