LS845 SOIC 8L

Overview

The LS845 is a low-noise, monolithic dual N-channel JFET amplifier from the LS844 series. It features an input capacitance of 8 pF maximum and a voltage noise density of 3.0 nV/√Hz at 1 kHz. The device offers a gate leakage current of 50 pA typical and a transconductance of 1500 µS typical. Maximum offset voltage is 15 mV with a drift of 25 µV/°C. It operates within a junction temperature range of -55°C to +150°C.

Feature Summary

• Ultra-low input capacitance reduces intermodulation distortion
• Monolithic construction ensures tight differential matching and thermal tracking
• Low noise profile with nearly zero popcorn noise
• High common-mode rejection ratio for precision applications

Applications

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

Procurement Notes

Verify the specific suffix indicates the SOIC-8L package configuration. Confirm RoHS compliance status if required by your manufacturing standards. Ensure the ordering code matches the exact LS845 variant needed for your circuit design parameters. Cross-reference the datasheet revision date to ensure you are using the latest electrical characteristics and absolute maximum ratings.

Selection Notes

Select the LS845 when minimizing input capacitance is critical for reducing intermodulation distortion in high-frequency circuits. Choose this component over higher capacitance alternatives like the LSK389 when simpler circuit designs with fewer devices are preferred. Consider the LS845 for applications requiring tight offset voltage matching and low drift across wide temperature ranges.

Part Context

The LS845 belongs to the LS844 series of low-noise, low-capacitance monolithic dual N-channel JFETs. This series is designed to combine low noise levels with significantly lower gate-to-drain capacitance compared to similar industry products. The LS845 specifically targets precision instrumentation and sensor applications where minimal input error and high accuracy are required.

Replacement Considerations

The LS844 TO-71 6L and SOIC 8L packages are fit, form, and pin compatible with the LSK389 product. Designers may consider the LSK389 as a substitute, noting that it has higher gate-to-drain capacitance (25pF vs 4pF) but comparable noise levels.

FAQ

What is the maximum input capacitance for the LS845?

The maximum common source input capacitance (CISS) for the LS845 is 8 pF.

How does the LS845 compare to the LSK389 regarding capacitance?

The LS845 features much lower gate-to-drain capacitance (4pF typical) compared to the LSK389 (25pF), enabling simpler circuit designs with reduced intermodulation distortion.

What is the typical voltage noise density of the LS845?

The LS845 has a voltage noise density of 3.0 nV/√Hz at 1 kHz with a 1 Hz noise bandwidth.