DS1085LZ-25+

Overview

The DS1085LZ-25+ is a dual-output frequency synthesizer from Analog Devices/Maxim Integrated, operating on a single 5V supply. It generates a main oscillator output (OUT1) ranging from 8.1kHz to 133MHz and a reference oscillator output (OUT0) from 8.2MHz to 133MHz. The device features a 2-wire serial interface for user-programmable frequency synthesis with three resolution options; the -25 suffix indicates a 25kHz step size. It includes nonvolatile EEPROM memory to store frequency settings, ensuring default values persist after power cycles. The internal master oscillator operates between 66MHz and 133MHz.

Feature Summary

• Dual synchronous outputs: Main oscillator (8.1kHz–133MHz) and reference oscillator (8.2MHz–133MHz)
• 2-wire serial interface for dynamic or factory programming of frequency parameters
• Nonvolatile EEPROM storage for master oscillator, prescaler, and divider settings
• 0.75% absolute accuracy with no external timing components required

Applications

• Standalone clock generation for digital systems
• Processor-controlled peripheral devices requiring dynamic frequency modification
• Systems needing synchronized multi-frequency clock sources

Procurement Notes

Verify the specific ordering suffix matches the required frequency step size, as the DS1085 family includes variants with 10kHz, 25kHz, and 50kHz resolutions. Confirm package type compatibility, as the standard variant uses a 150mil SOIC package. Ensure the application voltage aligns with the specified 5V supply requirement. Check for updated datasheets regarding electrical characteristics over temperature ranges.

Selection Notes

Select the DS1085LZ-25+ when a 25kHz frequency resolution is required for the main oscillator output. Compare against DS1085Z-10 and DS1085Z-50 if different step sizes are needed. Consider the OFFSET register range capabilities when targeting frequencies near the 66MHz to 133MHz master oscillator boundaries. Verify that the 2-wire bus speed requirements (standard or fast mode) are supported by the host controller.

Part Context

The DS1085 belongs to the EconOscillator family of frequency synthesizers. It replaces discrete crystal and oscillator circuits by integrating the master oscillator, prescalers, and dividers into a single IC. The device allows for thousands of user-specified frequencies through programmable registers, offering flexibility in system design without external timing components.

Replacement Considerations

Direct replacements within the same family include DS1085Z-10 (10kHz step) and DS1085Z-50 (50kHz step). These share identical pinouts and functionality but differ in frequency resolution. Verify that the specific step size requirement of the application can be met by these alternatives.