Stanford SR554 Transformer Preamplifier

The SR554 is a low-noise, transformer-coupled preamplifier optimised for source impedances between 0.05Ω and 1kΩ. With an input noise of only 0.1 nV/√Hz, the SR554 can be used in a wide range of low-noise applications.

Features:

• Transformer-coupled input
• 0.1nV/ √Hz, input noise
• 0.1Hz to 40kHz bandwidth
• Gain or 100 or 500
• Single-ended and differential inputs
• >40dB isolation from DC to 500MHz
• Powered by SRS lock-in amplifiers

It is the ideal preamplifier for low-temperature synchronous detection applications where isolation between the experimental sample and the lock-in amplifier is critical.

The SR554 can operate in two modes. In "by-passed" mode, the instrument is simply a passive transformer with a turns ratio of 100, providing an overall voltage gain of 100. In the "non-bypassed" mode, an additional amplifier with a gain of 5 is added increasing the gain to 500 and providing a low-impedance (<1Ω). In the bypassed mode, the SR554 requires no external power. When using the output amplifier, ±20VDC must be supplied. The preamplifier connector on SRS lock-ins can be used to power the SR554.