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Low-noise preamplifier selection guide

Current/Voltage converter for micro current amplification

  • Supports a wide range of current signals between ultra-low currents less than fA and 1µA
  • Combines high gain with wide frequency response
  • Low noise on the order of sub-fA/√Hz (10-16)

Information

Lineup

Gain (V/A) Frequency response Equivalent input noise current density
SA-604F2 10M DC to 500kHz 45fA/√Hz
SA-605F2 100M DC to 250kHz 15fA/√Hz
SA-606F2 1G DC to 100kHz 6fA/√Hz
SA-607F2 10G DC to 20kHz 2.5fA/√Hz
SA-608F2 100G DC to 2kHz 0.6fA/√Hz
SA-609F2 1T DC to 300Hz 0.4fA/√Hz

Input voltage - Frequency response

The model line-up supports a wide current input range. Includes extremely ultra-low currents order of sub-pA.

Conversion gain - Frequency response

High gain and wide frequency response

*Survey conducted Dec 14, 2022

Output noise - Frequency response

Achieved the world's lowest noise characteristics

*Survey conducted Dec 14, 2022

Pulse response

Output waveform comparison at square wave small signal input

SA-604F2 (DC to 500kHz, 45fA/√Hz) [Input current: 100nAp-p]

10Hz
1kHz
10kHz
100kHz

SA-605F2 (DC to 250kHz, 15fA/√Hz) [Input current: 10nAp-p]

10Hz
1kHz
10kHz
100kHz

SA-606F2 (DC to 100kHz, 6fA/√Hz) [Input current: 1nAp-p]

10Hz
1kHz
10kHz
100kHz

SA-607F2 (DC to 20kHz, 2.5fA/√Hz) [Input current: 0.1nAp-p]

10Hz
100Hz
1kHz
10kHz

SA-608F2 (DC to 2kHz, 0.6fA/√Hz) [Input current: 10pAp-p]

1Hz
10Hz
100Hz
1kHz

SA-609F2 (DC to 300Hz, 0.4fA/√Hz) [Input current: 1pAp-p]

0.1Hz
1Hz
10Hz
100Hz

Built-in LPF set to THRU

Measurement example

Challenging the limits of signal detection (fA real-time signal)

Small signals amplified by the SA series are observed with an oscilloscope (bandwidth 1 MHz).

SA-609F2

  • Input: 10fAp-p@0.3Hz
  • Built-in LPF setting: 3Hz
Y:5mV/div.
  • Input: 30fAp-p@30Hz
  • Built-in LPF setting: THRU
Y: 20mV/div.

Real-time detection of 10fAp-p and 30fAp-p micro signals

Challenging signal detection limits (fA repetitive signal)

Connect multiple SA series units and observe using the averaging function of the oscilloscope.

Measurement example

SA-609F2

  • Input: 1fAp-p@0.5Hz,
    Pulse width: 500ms
  • LPF setting: 3Hz
  • Averaging process: 1,000 times

SA-607F2

  • Input: 10fAp-p@55Hz,
    Pulse width: 3.64ms
  • LPF setting: 1kHz
  • Averaging process: 10,000 times

Successfully detected 1fAp-p and 10fAp-p signals

Performance comparison with competitors

Pulse waveform responses

NF's amplifiers are capable of capturing signal changes at higher speeds.

  • Input current: ±1nA
  • Gain: 10G (V/A)
Input signal frequency 100Hz
(x-axis: 2ms/div)
1kHz
(x-axis: 200µs/div)
10kHz
(x-axis: 20µs/div)

SA-607F2

Current Amplifier A

Current Amplifier C

*Survey conducted June 16, 2017

SA-609F2

  • Input current: ±10pA
  • Gain: 1T (V/A)
Input signal frequency 1Hz
10Hz
100Hz

SA-609F2

Current Amplifier A

*Survey conducted Dec 14, 2022

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