LSK489B SOIC 8L ROHS

Overview

The LSK489B is a low noise, monolithic dual N-channel JFET amplifier in an SOIC-8 package. It features a typical input capacitance of 4pF and a noise voltage of 1.8nV/√Hz at 1kHz. The device offers a common mode rejection ratio of 102dB and a gate-to-source breakdown voltage of 60V. Operating temperatures range from -55°C to +150°C. The B grade specifies a drain saturation current (IDSS) range of 8.0mA to 15.0mA.

Feature Summary

• Monolithic dual N-channel JFET construction with interleaved design for excellent matching and thermal tracking
• Industry-leading low input capacitance of 4pF to reduce intermodulation distortion
• Ultra-low noise profile with minimal popcorn noise characteristics
• Tight differential voltage match and low offset drift over temperature

Applications

• Wideband differential amplifiers
• High speed temperature compensated single ended input amplifiers
• High speed comparators
• Impedance converters
• Sonobuoys and hydrophones
• Acoustic sensors

Procurement Notes

Verify the specific suffix 'B' corresponds to the required IDSS range of 8.0mA to 15.0mA. Confirm the package type matches the SOIC-8 requirement. Ensure the manufacturer designation aligns with Linear Integrated Systems specifications. Check RoHS compliance status if required by the application environment. Validate that the operating temperature range meets system constraints.

Selection Notes

Select this component when minimizing input capacitance is critical for reducing intermodulation distortion in high-speed circuits. The B grade provides a higher IDSS range compared to the A grade. Consider the SOIC-8 package for surface mount applications requiring fit, form, and pin compatibility with the LSK389 series. Evaluate the trade-off between slightly higher noise versus significantly lower capacitance compared to other dual JFET options.

Part Context

The LSK489 is designed as a precision instrumentation component offering superior matching through its monolithic silicon construction. It serves as a direct replacement for the LSK389 in TO-71 and SOIC packages, maintaining identical pinouts while providing drastically reduced gate-to-drain capacitance. This reduction facilitates simpler circuit designs with fewer devices.

Replacement Considerations

The LSK489 is pin-compatible with the LSK389 in both TO-71 and SOIC packages. Designers can interchange these components directly without schematic modifications. Verify that the specific IDSS grade requirements are met by the selected variant.

FAQ

How does the LSK489 compare to the LSK389 regarding capacitance?

The LSK489 features a significantly lower gate-to-drain capacitance of 4pF compared to the 25pF found in the LSK389, while maintaining similar noise performance.

What is the difference between the LSK489A and LSK489B grades?

The primary difference is the Drain Saturation Current (IDSS) range. The A grade has an IDSS of 2.5mA to 8.5mA, while the B grade has an IDSS of 8.0mA to 15.0mA.

Is the LSK489 compatible with single-channel designs?

Yes, for equivalent single N-channel versions, refer to the LSK189 datasheet.