Low-noise preamplifier selection guide
Differential input type
- Reliably amplify a wide range of voltage signals between sub-µV and several mV
- Lineup of models supporting a wide frequency range between DC and up to 500MHz
- The most suitable model can be selected according to the signal source resistance.
![](images/sa_440f5-1.jpg)
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Information
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Measurement example
Information
Lineup
Input type | Gain | Bandwidth | Input resistance | Noise voltage density | Noise current density | Noise figure | |
---|---|---|---|---|---|---|---|
SA-410F3 | Differential input | 40dB | DC to 1MHz |
1kΩ/ 10kΩ/ 100kΩ |
0.75nV/√Hz | 4.5pA/√Hz | - |
SA-420F5 | 46dB | 1kHz to 80MHz |
1MΩ | 0.9nV/√Hz | 100fA/√Hz | - | |
SA-421F5 | 46dB | 30Hz to 30MHz |
1MΩ | 0.5nV/√Hz | 100fA/√Hz | - | |
SA-430F5 | 46dB | 1kHz to 100MHz |
50Ω | 0.35nV/√Hz | 7pA/√Hz | 1.0dB | |
SA-440F5 | 40dB | DC to 20MHz | 1MΩ/ 100MΩ/ OPEN |
1.8nV/√Hz | 25fA/√Hz | - |
Input voltage - Frequency response
The model line-up supports a wide voltage input range. Includes extremely small voltages of less than 1 μV.
![](images/400_img00_resize.jpg)
Output noise - Frequency response
Supports models with frequency ranges up to 100MHz. Achieves low noise specifications compared to competitors.
![](images/400_img01_JP2.jpg)
Output noise - Input impedance Characteristics
An amplifier suitable for the signal source resistance of the sensor can be selected. Achieves low-noise signal output.
![](images/400_img02_JP2.jpg)
Pulse response
Output waveform comparison at 100μVp-p square wave input
SA-410F3 (DC to 1MHz, 0.75nV/√Hz)
![](images/SA410_100_w120.gif)
![](images/SA410_010k_w120.gif)
![](images/SA410_100k_w120.gif)
![](images/SA410_001M_w120.gif)
SA-420F5 (1kHz to 70MHz, 0.9nV/√Hz)
![](images/SA420_001k_w120.gif)
![](images/SA420_100k_w120.gif)
![](images/SA420_010M_w120.gif)
![](images/SA420F5_30MHz-1.jpg)
SA-421F5 (30Hz to 30MHz, 0.5nV/√Hz)
![](images/SA421_001k_w120-1.gif)
![](images/SA420_100k_w120-1.gif)
![](images/SA420_010M_w120-1.gif)
![](images/SA421F5_30MHz.jpg)
SA-430F5 (1kHz to 100MHz, 0.35nV/√Hz)
![](images/SA430_001k_w120.gif)
![](images/sa430_10M_w120.gif)
![](images/SA430F5_30MHz.jpg)
![](images/SA430F5_100MHz.jpg)
SA-440F5 (DC to 20MHz, 1.8nV/√Hz)
![](images/SA440_100_w120.gif)
![](images/SA440_100k_w120.gif)
![](images/SA440_001M_w120.gif)
![](images/SA440_010M_w120.gif)
Measurement example
Challenging the signal detection limit (µV real-time signal)
Small signals amplified by the SA series are observed with an oscilloscope.
SA-410F3
- Input signal: 5μVp-p, sine wave
- Oscilloscope: 1MHz bandwidth
- LPF: Connected after the amplifier and set a cutoff frequency about 5 times the signal frequency*
![](images/sa410_sine_55Hz_LPF300Hz_w120.gif)
LPF=300Hz
![](images/sa410_sine_55Hz_LPF300Hz_w120.gif)
LPF=3kHz
![](images/sa410_sine_5500Hz_LPF30kHz_w120.gif)
LPF=30kHz
![](images/sa410_sine_55kHz_LPF300kHz_w120.gif)
LPF=300kHz
Detects 5µVp-p real-time signals
Waveform without LPF
*Using an appropriate LPF can reduce overall noise as shown above.
![](images/sa410_sine_55kHz_LPF1MHz_w120-1.gif)
Challenging the signal detection limit (nV repetitive signal)
Connect multiple SA series units and observe using the averaging function of the oscilloscope.
Measurement block diagram
![](images/fig_sa410_block_2_new.jpg)
Measurement results
SA-410F3
- Input: 4nVp-p@55Hz, Pulse width: 1.82ms
- Measurement bandwidth: 1kHz
- Averaging process: 10,000 times
![](images/sa410_5v_10000.jpg)
4nVp-p signal detected