SRS SR554 Transformer Preamplifier
- Transformer-coupled input
- 0.1 nV/√Hz input noise
- 0.1 Hz to 40kHz bandwidth
- Gain of 100 or 500
- Single-ended and differential inputs
- >40 dB isolation from DC to 500 MHz
- Powered by SRS lock-in amplifiers
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The Stanford Research Systems SR554 is a low-noise, transformer-coupled preamplifier optimised for source impedances between 0.05 Ω and 1 kΩ. With an input noise of only 0.1 nV/√Hz, the SRS SR554 can be used in a wide range of low-noise applications.
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 one of two modes. In the "bypassed" 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.
| Mode | Single-ended or differential |
| Noise | 0.1 nV/√Hz |
| Source impedance | 0.05 Ω to 1 kΩ (recommended) |
| CMRR | >120 dB below 1 kHz |
| Comman mode range | Primary can float to ±100 VDC |
| Gain | 100× (Transformer only) |
| 500× (Transformer and buffer) | |
| Max frequency response (1V input) | 0.1 Hz to 40 kHz |
| Isolation | >40 dB, DC to 500 MHz |
| Output | Single-ended or differential |
| Maximum output | 100 Vpp (Transformer only) |
| 20 Vpp (Transformer and buffer) | |
| Output impedance | >5 kΩ (Transformer only) |
| Dimensions and weight | 3.75" × 3.0" × 7.5" (WHL), 4 lbs. |
| Power | Supplied by SRS lock-ins. Ext. ±20 VDC supplies can also power the SR554. |
| Warranty | One year parts and labor on defects in materials and workmanship |
Stanford Research Systems SR554 datasheet 
