DS1087LU-447+

Overview

The DS1087LU-447+ is a factory-programmed, spread-spectrum clock generator from the EconOscillator family. It produces a dithered square-wave output with frequencies ranging from 130kHz to 66.6MHz. The device operates on a single 2.7V to 3.6V supply and features nonvolatile EEPROM storage for settings. Key electrical parameters include an active supply current of up to 5mA and a standby current of 5µA in power-down mode. It supports a 2-wire serial interface for configuration and offers selectable 2% or 4% dithering to reduce electromagnetic interference.

Feature Summary

• Factory programmed square-wave generator with frequencies up to 66.6MHz
• Spread-spectrum capability with 2% or 4% selectable dithering for EMI reduction
• Nonvolatile EEPROM storage retains settings without external backup power
• Glitchless output-enable control and programmable power-down mode

Applications

• Printers
• Copiers
• PCs
• Computer Peripherals
• Cell Phones

Procurement Notes

Verify the specific frequency and dither percentage associated with the -447 suffix against the manufacturer's ordering guide, as this code denotes a custom factory setting rather than a standard option. Confirm the package type is the 8-pin µSOP (118 mils) and ensure the operating temperature range meets the -40°C to +85°C requirement. Check for RoHS compliance status if required by the assembly process.

Selection Notes

Select the DS1087LU-447+ when a fixed, glitch-free clock source with spread-spectrum benefits is needed without external timing components. Ensure the system voltage falls within the 2.7V to 3.6V range. Use the 2-wire interface if dynamic reconfiguration of the prescaler or dither amount is required during operation. Consider the 8-pin µSOP package constraints for PCB layout.

Part Context

The DS1087L series replaces traditional crystal oscillators and ceramic resonators with a silicon-based solution. The 'LU' designation indicates the commercial/industrial temperature grade (-40°C to +85°C) and the µSOP package. The '-447+' suffix identifies a specific custom frequency and dither configuration programmed at the factory, distinguishing it from standard frequency options like the DS1087LU-216.

Replacement Considerations

Direct replacements must match the 8-pin µSOP footprint and 2.7V-3.6V supply range. Standard alternatives within the DS1087L family include DS1087LU-216 (16.6MHz, 2% dither) or DS1087LU-466 (66.6MHz, 4% dither). Verify that any substitute supports the required 2-wire serial interface and nonvolatile memory features if in-circuit programming is necessary.

FAQ

How is the spread-spectrum dither controlled?

Dither is enabled via the SPRD pin and configured using the J0 bit in the PRESCALER register. Setting J0 high selects 2% peak dither, while low selects 4% peak dither.

What happens to the output during power-down?

When the PDN pin is low, the master oscillator is disabled. The output enters a power-down state, drawing only 5µA of standby current. The synchronous enable ensures no glitches occur when exiting this mode.

Can the device operate without a microprocessor?

Yes, in stand-alone mode. If in-circuit programming is not required, SDA and SCL pins can be tied high to VCC, allowing the device to output its factory-programmed frequency immediately upon power-up.