CY670A Cryogenic Silicon Diode Temperature Sensor

Supported Applications

The Omega CY670 Series consists of silicon diode temperature sensors designed for cryogenic and low-temperature applications. These sensors are intended for use with compatible instrumentation systems to measure temperatures across a broad range from deep cryogenics up to room temperature and beyond.

• Cryogenic measurement
• Low-temperature sensing

Operating Conditions & Performance

The CY670 Series operates over a process temperature range of 1.4 to 500 K, with specific adapter configurations supporting ranges up to 325 K or 475 K depending on the model. The sensors conform to standard curve CY670 and require an external current source for operation.

• Recommended Excitation: 10 µA, ±0.1%
• Max Reverse Voltage: 60V
• Dissipation at Recommended Excitation: 16 µW @ 4.2 K; 10 µW @ 77 K; 5 µW @ 300 K

Sensitivity varies with temperature, ranging from approximately -12.5 mV/K at 1.4 K to -2.30 mV/K at 305 K. Response times for the SD model are typically <10 ms @ 4.2 K, 100 ms @ 77 K, and 200 ms @ 305 K.

Configuration Options

The series offers multiple mounting configurations to accommodate different installation requirements, including screw-in adapters, clamp styles, copper bobbins, and bare chip options. Wetted materials include silicon, beryllium oxide, copper, and phosphor-bronze wire.

Mounting Adapters

• CY670-SD: Basic sensor package style (flat)
• CY670-CO: Spring-loaded brass clamp for removable mounting
• CY670-LR: Cylindrical copper adapter
• CY670-MT: Metric-threaded copper adapter
• CY670-ET: SAE-threaded copper adapter (screw-in)
• CY670-CU/DI/CY: Copper disk or bobbin configurations with thermal anchoring via epoxy
• CY670-BO: Bolt-on copper block with beryllium oxide thermal link

Accuracy Tolerance Bands

The series is available in five tolerance bands (A, B, C, D, E) to meet varying precision requirements across the temperature range:

• Band A: ±0.25 K (2 to 100 K), ±0.50 K (100 to 305 K)
• Band B: ±0.50 K (2 to 305 K), ±0.33% of T (305 to 500 K)
• Band C: ±1.0 K (2 to 305 K), ±0.5% of T (305 to 500 K)
• Band D (PRT Band): ±1.5 K (2 to 30 K), ±0.25 K (30 to 100 K), ±0.30 K (100 to 305 K), ±0.1% of T (305 to 500 K)
• Band E (Bare Chip Band): ±1.0 K (2 to 30 K), ±0.25 K (30 to 100 K), percentage-based tolerances above 100 K

Key Product Differences

Differences within the CY670 Series are defined by the physical package style and the selected accuracy tolerance band.

• The SD (flat sensor) and CO (clamp style) adapters support a temperature range of 1.4 to 500 K or up to 475 K depending on configuration, while most other copper-based adapters are rated for 1.4 to 325 K.
• Band E is designated as the "Bare Chip Band" and includes options such as CYC670E-BR-10 (package of 10).
• The CU, DI, and CY mounting adapters serve as their own sample thermal anchor; the PI and CY adapter can be used only in a two-wire configuration.

Caution notes indicate that use is recommended for low-level radiation environments. The sensors are not recommended for magnetic field applications below 60 K due to high dependence, though they exhibit low magnetic field dependence up to 5 tesla above 60 K.