LS844: Low-Noise Dual JFET for High-Performance Audio & Precision Analog
- JC - Linear Systems
- Oct 24
- 2 min read
When designing high-impedance, low-noise front ends—whether for audio preamps, instrumentation nodes, or sensor interfaces—the input stage is everything. The LS844 Dual N-Channel JFET from Linear Integrated Systems is engineered specifically for these precision applications, offering low noise, low input capacitance, and tight device matching on a single, monolithic die.
This combination allows designers to extract maximum signal fidelity across a wide range of applications—from high-end audio to ultra-sensitive sensor readout.
What Makes the LS844 Unique?
Unlike typical dual JFETs, the LS844 integrates both JFET devices on the same piece of silicon, which ensures:
Excellent Vgs matching
Superior thermal tracking
High common-mode rejection (102 dB CMRR)
Consistent, predictable performance across temperature
This tight pairing is essential in differential input stages—and is a core reason high-end audio designers choose the LS844.
In addition, the LS844 offers:
Feature | Benefit |
Low Noise: 2.5 nV/√Hz @ 1 kHz (typ.) | Preserves detail in low-level signals |
Low Input Capacitance (~4 pF) | Reduces IMD and improves high-frequency cleanliness |
Nearly Zero Popcorn Noise | Eliminates burst-style distortion artifacts |
SOT-23-6 (RoHS) | Compact, modern, surface-mount friendly |
Why It Performs Better Than High-Capacitance JFETs
In many audio and instrumentation circuits, input capacitance is the hidden source of distortion—especially when working with high-impedance sources.
JFETs with high gate capacitance require additional cascode circuitry to prevent nonlinear capacitance from producing intermodulation distortion. The LS844 avoids this issue through its very low capacitance, enabling simpler, cleaner designs that preserve clarity across frequency.
The LS844 maintains high input impedance even as frequency rises, significantly improving distortion performance in comparison to high-capacitance devices.
Ideal Application Areas
✅ High-End Audio Preamplifiers✅ Microphone Preamps (Dynamic & Condenser)✅ Phono Preamplifiers (MM / MC)✅ Sensor & Charge Amplifier Interfaces (Piezo, MEMS, Electret)✅ Discrete Operational Amplifiers✅ Low-Level Measurement & Electrometry
The LS844 is used anywhere the signal is small, the input impedance must be high, and noise must be preserved—not added.
Example: High-Performance Audio Phono Stage
The LS844 excels in phono front-ends, where the cartridge impedance interacts directly with input capacitance.
Because of its low input capacitance, the LS844 reduces:
High-frequency noise rise
Cartridge interaction distortion
Harmonic and intermodulation artifacts
This results in cleaner, more natural analog reproduction—especially noticeable in cymbals, strings, and spatial ambiance.
Resources & Links
Item | Link |
LS844 Datasheet | |
LS844 Application Note (Detailed Design Guidance) | |
Request Samples / Quotes / Technical Assistance |
Final Thoughts
For designers who demand:
Low noise
High matching precision
Low capacitance
High input impedance
And sonic or measurement transparency
The LS844 offers one of the strongest performance combinations in the industry.
Whether you are designing a reference-grade audio signal chain or an ultra-low-current sensor measurement stage, the LS844 provides the clarity, control, and stability needed for true precision.
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