The Stanford Research Systems QCM25 is a 5 MHz crystal oscillator engineered to serve as the frequency reference component in Quartz Crystal Microbalance (QCM) systems. It generates a precise, stable reference signal for applications demanding accurate mass and viscosity measurements. The QCM25 integrates with the SRS QCM200 controller to enable real-time monitoring of surface phenomena, thin-film deposition, and molecular interactions across scientific research, laboratory analysis, and industrial process control.
Technical Specifications
• Nominal Frequency: 5 MHz
• Crystal: AT-cut, plano-plano quartz wafer, 1 inch diameter
• Electrodes: Chromium/gold (standard); Titanium/gold, Titanium/platinum, and Indium Tin Oxide alternatives available
• Output Signal: TTL square wave, 0 to 10.625 VDC
• Output Impedance: 50 Ω
• Series Resonance Resistance (Unsupported): Approximately 5 kΩ
• Frequency Resolution: 0.01 Hz (10 sec gate), 0.1 Hz (1 sec gate), 1.0 Hz (0.1 sec gate)
• Frequency Stability: 0.002 Hz second-to-second; 0.10 Hz minute-to-minute; 8 Hz/°C temperature coefficient
• Crystal Frequency Accuracy: ±100 ppm (±500 Hz)
• External Timebase Input: 10 MHz precision reference with ±10 ppm pull range
• Mass Measurement Range: Micrograms to submonolayer fractions of a nanogram
– Key Features
• Supports crystal operation in solutions up to 88% glycerol (w/w)
• Dual analog outputs: Frequency (0 to ±10 VDC, 20-bit resolution, selectable ±2 to ±200 kHz ranges) and Conductance (0 to 10.625 VDC)
• Phase-lock capability to external 10 MHz timebase for enhanced long-term stability
• 1 kΩ source impedance on analog outputs, compatible with precision multimeters and ADCs
– Typical Applications
Surface science and thin-film characterization, biosensor development, polymer analysis, and real-time process monitoring where submonolayer mass resolution is required.
– Compatibility & Integration
Connects directly to the QCM200 controller via 3-foot Cat-5 cable (RJ-45 connectors). Crystal Holder interfaces via BNC connector for the 5 MHz crystal signal.
