LTC6904CMS8#PBF

Programmable Timers And Oscillators Overview

The LTC6904CMS8#PBF is a low-power, self-contained digital frequency source manufactured by Analog Devices Inc. It provides a precision square wave output ranging from 1kHz to 68MHz, programmable via an industry-standard I2C serial interface. The device operates on a single supply voltage between 2.7V and 5.5V and requires no external components other than a power supply bypass capacitor. Key electrical specifications include a typical initial frequency accuracy of 0.5%, a maximum operating frequency of 68MHz, and a typical supply current of 1.7mA at frequencies below 1MHz with a 2.7V supply. The unit is housed in an 8-lead plastic MSOP package.

Programmable Timers And Oscillators Feature Summary

• I2C Compatible Interface: Utilizes a standard 2-wire I2C serial port for programming, allowing easy integration with microcontrollers.
• Wide Frequency Range: Generates precise square waves from 1kHz to 68MHz using a proprietary feedback loop that linearizes the relationship between digital control settings and frequency.
• High Accuracy: Offers 0.5% typical initial frequency accuracy and less than 1.1% total frequency error across all settings.
• Low Power Consumption: Draws only 1.7mA typical supply current at frequencies under 1MHz with a 2.7V supply.

Programmable Timers And Oscillators Applications

• Precision Digitally Controlled Oscillator
• Power Management Systems
• Replacement for Direct Digital Frequency Synthesis (DDS)
• Switched Capacitor Filter Clock

Programmable Timers And Oscillators Procurement Notes

Verify the specific temperature grade and package variant when ordering. The CMS8 suffix indicates a commercial temperature range (0°C to 70°C) guaranteed performance, while functional operation is supported from -40°C to 85°C. Ensure the I2C address configuration via the ADR pin matches the system design, as this determines the slave address bits. Confirm lead-free finish compliance if required by assembly standards.

Programmable Timers And Oscillators Selection Notes

Select the LTC6904 over the LTC6903 when an I2C interface is preferred over SPI. Choose the CMS8 package for commercial applications requiring 0°C to 70°C guaranteed performance. For wider industrial or military temperature ranges, consider the IMS8 (-40°C to 85°C), HMS8 (-40°C to 125°C), or MPMS8 (-55°C to 125°C) variants. Ensure the load capacitance on CLK outputs does not exceed 5pF to maintain specified accuracy without additional buffering.

Programmable Timers And Oscillators Part Context

This component belongs to the LTC6903/LTC6904 family of silicon oscillators. While the LTC6903 uses an SPI-compatible interface, the LTC6904 specifically implements an I2C-compatible interface. Both share identical internal architectures, frequency ranges, and electrical characteristics, differing primarily in their serial communication protocols and the function of Pin 4 (SEN vs. ADR).

Programmable Timers And Oscillators Replacement Considerations

The LTC6903 is a functional alternative if the system supports SPI instead of I2C. For lower frequency requirements up to 20MHz, the LTC6900 offers a similar form factor. Higher frequency operations up to 30MHz can be addressed by the LTC1799. Verify interface compatibility and pin assignments before substitution.