The Stanford Research Systems SR570 is a low-noise current preamplifier engineered for precise amplification of small currents from transducers such as photodiodes and Faraday cups. It delivers selectable gain from 1 pA/V to 1 mA/V with vernier adjustment in 0.5% steps, input noise of 5 fA/√Hz, and maximum bandwidth to 1.00 MHz. The instrument features configurable gain allocation across three modes—Low-Noise, High-Bandwidth, and Low-Drift—to optimize performance for specific measurement conditions.
Technical Specifications
• Current Sensitivity: 1 pA/V to 1 mA/V in 1-2-5 sequence; vernier adjustment in approximately 0.5% steps
• Input Noise: 5 fA/√Hz
• Maximum Bandwidth: 1.00 MHz
• Maximum Input Current: ±5 mA
• Input Offset Current Adjustment: ±1 pA to ±1 mA in approximately 0.1% increments
• Input DC Bias Voltage: ±5 V adjustable
• Input Ground Floating Range: ±40 V relative to chassis ground
• Filter Cutoff Frequency Range: 0.03 Hz to 1 MHz in 1-3-10 sequence
– Key Features
• Three gain allocation modes: Low-Noise Mode for superior front-end performance, High-Bandwidth Mode for enhanced frequency response, and Low-Drift Mode reducing DC drift by a factor of 1000 using low input-current op-amps
• Two configurable first-order RC filters with 6 dB/octave response (12 dB/octave cascaded); selectable low-pass, high-pass, or band-pass configurations
• Front-panel frequency response compensation for source capacitance
• Variable input offset current suppression for DC background rejection
• Front-panel filter reset button for rapid recovery from long time constant overloads
• Opto-isolated RS-232 interface (9600 baud, 8 data bits, no parity, 2 stop bits)
• Two rear-panel opto-isolated TTL inputs: blanking input for gain enable/disable and toggle input for gain sign inversion
– Typical Applications
Photodiode measurements, Faraday cup current detection, and other sensitive current measurement tasks requiring low-noise amplification and flexible filtering.
– Compatibility & Integration
RS-232 control via opto-isolated interface. TTL inputs support external blanking and toggle control. Fully floating input ground accommodates high common-mode voltages to ±40 V.
