LTC6904HMS8#PBF

Programmable Timers And Oscillators Overview

The LTC6904HMS8#PBF is a low-power, self-contained digital frequency source manufactured by Analog Devices. It generates precise square wave frequencies ranging from 1kHz to 68MHz via an I2C compatible serial interface. The device requires no external components other than a power supply bypass capacitor and operates on a single supply voltage between 2.7V and 5.5V. Key electrical specifications include a typical initial frequency accuracy of 0.5%, a total frequency error of less than 1.1% across all settings, and a typical frequency drift of 10ppm/°C over temperature. Supply current is typically 1.7mA at frequencies below 1MHz with a 2.7V supply.

Programmable Timers And Oscillators Feature Summary

• I2C Compatible Serial Interface for digital frequency programming
• Frequency Range: 1kHz to 68MHz Square Wave Output
• 0.5% Typical Initial Frequency Accuracy
• Single Supply Operation: 2.7V to 5.5V
• Low Power Consumption: 1.7mA Typical (f < 1MHz, VS = 2.7V)
• Jitter: <0.4% Typical (1kHz to 8MHz)

Programmable Timers And Oscillators Applications

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

Programmable Timers And Oscillators Procurement Notes

Verify the specific suffix '#PBF' indicates Lead-Free finish and Tube packaging when ordering. Confirm the 'H' grade designation ensures operation within the –40°C to 125°C temperature range. Ensure the host system supports standard I2C protocols for communication with the slave address determined by the ADR pin state.

Programmable Timers And Oscillators Selection Notes

Select the LTC6904HMS8#PBF for applications requiring I2C control rather than SPI. The 'H' suffix denotes the extended industrial temperature range of –40°C to 125°C. The MSOP-8 package is suitable for space-constrained designs. Consider the 5pF capacitive load limit on outputs; use buffering if driving larger loads or long traces to maintain accuracy above 1MHz.

Programmable Timers And Oscillators Part Context

This component belongs to the LTC6903/LTC6904 family of programmable oscillators. While the LTC6903 utilizes an SPI interface, the LTC6904 variant specifically employs an industry-standard I2C interface. Both share identical electrical characteristics, frequency ranges, and internal architectures, differing primarily in their serial communication protocol.

Programmable Timers And Oscillators Replacement Considerations

The LTC6903HMS8#PBF serves as a functional replacement if the application can accommodate an SPI interface instead of I2C. Other Linear Technology oscillators like the LTC6900 or LTC1799 offer different frequency ranges or package types but lack the specific I2C programmability of this model.

Programmable Timers And Oscillators FAQ

How is the output frequency calculated?

The frequency is determined by the equation f(Hz) = 2^OCT * 2078 / (2 - DAC/1024), where OCT is a 4-bit code and DAC is a 10-bit code programmed via the serial interface.

What determines the I2C slave address?

The first 6 bits are factory-programmed to 001011. The 7th bit (LSB) is determined by the logic level on the ADR pin (Pin 4). ADR Low results in address 0010111, and ADR High results in 0010110.

What is the maximum capacitive load allowed?

The device is designed to drive up to 5pF on each output without degradation in accuracy. Driving more than 5pF may require a high-speed buffer to maintain performance.