Summary of ICs need no caps linear Tech timer and oscillator
The LTC6990 is a precision silicon oscillator from Linear Technology's TimerBlox family, offering a programmable frequency range of 488Hz to 2MHz. It functions as either a fixed-frequency or voltage-controlled oscillator (VCO), programmed using one or two resistors. Designed for low power and high stability, it operates on a single supply between 2.25V and 5.5V, features CMOS logic outputs, and withstands extreme temperatures, vibration, and acceleration. Its compact SOT-23 or DFN packaging makes it ideal for portable and battery-powered equipment, serving as a reliable replacement for crystal oscillators without requiring capacitors.
Parts used in the LTC6990 Project:
- LTC6990 Precision Silicon Oscillator
- RSET Resistor (Single resistor for fixed frequency)
- VCO Resistors (Two resistors for VCO center frequency and tuning range)
- SOT-23 (ThinSOT) Package
- DFN Package (2mm × 3mm)
Description
The LTC®6990 is a precision silicon oscillator with a programmable frequency range of 488Hz to 2MHz. It can be used as a fixed-frequency or voltage-controlled oscillator (VCO). The LTC6990 is part of the TimerBlox® family of versatile silicon timing devices.
A single resistor, RSET, programs the LTC6990’s internal master oscillator frequency. The output frequency is determined by this master oscillator and an internal frequency divider, NDIV, programmable to eight settings from 1 to 128.
Applications
- Low Cost Precision Programmable Oscillator
- Voltage-Controlled Oscillator
- High Vibration, High Acceleration Environments
- Replacement for Fixed Crystal and Ceramic Oscillators
- Portable and Battery-Powered Equipment
Features
- Fixed-Frequency or Voltage-Controlled Operation
– Fixed: Single Resistor Programs Frequency with <1.5% Max Error
– VCO: Two Resistors Set VCO Center Frequency and Tuning Range - Frequency Range: 488Hz to 2MHz
- 2.25V to 5.5V Single Supply Operation
- 72μA Supply Current at 100kHz
- 500μs Start-Up Time
- VCO Bandwidth >300kHz at 1MHz
- CMOS Logic Output Sources/Sinks 20mA
- 50% Duty Cycle Square Wave Output
- Output Enable (Selectable Low or Hi-Z When Disabled)
- –55°C to 125°C Operating Temperature Range
- Available in Low Profile (1mm) SOT-23 (ThinSOT™) and 2mm × 3mm DFN Package
Linear Technology has released a set of simple small timing ICs, including: a voltage-controlled oscillator, a low frequency oscillator, four pulse width modulated oscillators, four monostable pulse generators and two delays.
Called TimerBlox, they are based around silicon oscillators and share a common pin-out.
“Like all Linear Technology silicon oscillators, TimerBlox devices are solid state and can be operated under high acceleration, vibration and temperature extremes,” claimed the firm. “They ensure accuracy and stability at a much higher level than typical resistor-capacitor-based oscillators.”
Each part can operate over a range of frequency or time, and is programmed with one to three resistors (scroll down).
For example, the VCO frequency range is 488Hz to 2MHz, 29µHz (9.5hr period) is the slowest output from the low frequency oscillator, and the timers run from 1µs to 34s.
“They eliminate the complexity of software programming and circuit design, while providing good accuracy, low power and a small footprint,” said Erik Soule, general manager at Linear Tech.
For more read: ICs need no caps linear Tech timer and oscillator
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What is the frequency range of the LTC6990?
The LTC6990 has a programmable frequency range of 488Hz to 2MHz. -
Can the LTC6990 be used as a voltage-controlled oscillator?
Yes, it can be used as a fixed-frequency or voltage-controlled oscillator (VCO). -
How many resistors are needed to program the LTC6990?
A single resistor programs the fixed frequency, while two resistors set the VCO center frequency and tuning range. -
What is the supply current at 100kHz?
The supply current is 72μA at 100kHz. -
Does the LTC6990 require external capacitors?
No, the device eliminates the complexity of circuit design that typically requires capacitors. -
What package options are available for the LTC6990?
It is available in a Low Profile 1mm SOT-23 (ThinSOT) and a 2mm × 3mm DFN package. -
What is the operating temperature range?
The operating temperature range is -55°C to 125°C. -
How does the output duty cycle behave?
The device provides a 50% duty cycle square wave output.
