Bourns has introduced the CRT-G series of precision thin film chip resistors for measurement, signal-conditioning and control circuits.
The thin film chip resistors family combines resistance tolerances down to ±0.01% with temperature coefficient options down to ±2 ppm/°C, depending on package size and resistance value. Nine case sizes provide different combinations of board area, power handling and electrical accuracy.
Key features and benefits
- Resistance values span 2.49 Ω to 3.3 MΩ across the family.
- Initial tolerance options are ±0.01%, ±0.05%, ±0.1%, ±0.25%, ±0.5% and ±1%.
- Temperature coefficient of resistance options are ±2, ±3, ±5, ±10, ±15, ±25 and ±50 ppm/°C.
- Package sizes extend from 01005 to 2512, with rated power from 0.031 W to 0.75 W at 70 °C.
- Operating temperature spans −55 °C to +155 °C, with power derated to zero at +155 °C.
- Tin-plated terminations, RoHS compliance, halogen-free construction and Moisture Sensitivity Level 1 support surface-mount assembly.
Tolerance and TCR address different parts of the circuit error budget. Initial tolerance governs resistance variation before temperature-related effects are considered; TCR governs resistance change with temperature. Selecting the tightest tolerance does not remove the need to assess temperature drift and load-related resistance change.
Technical highlights
Package size and power handling
| Model | Case size | Rated power at 70 °C |
|---|---|---|
| CRT01005G | 01005 | 0.031 W |
| CRT0201G | 0201 | 0.05 W |
| CRT0402G | 0402 | 0.063 W |
| CRT0603G | 0603 | 0.1 W |
| CRT0805G | 0805 | 0.125 W |
| CRT1206G | 1206 | 0.25 W |
| CRT1210G | 1210 | 0.25 W |
| CRT2010G | 2010 | 0.5 W |
| CRT2512G | 2512 | 0.75 W |
The smallest CRT01005G has body dimensions of 0.40 ±0.02 mm × 0.20 ±0.02 mm and a thickness of 0.13 ±0.02 mm. At the other end of the family, CRT2512G measures 6.30 ±0.15 mm × 3.20 ±0.15 mm, with a thickness of 0.55 ±0.10 mm.
Package selection also affects voltage capability. Maximum working voltage ranges from 15 V to 200 V across the family, while maximum overload voltage ranges from 30 V to 400 V. The allowable continuous voltage must satisfy both the power-derived rated voltage and the package’s maximum working voltage.
Full rated power applies up to 70 °C. Above that temperature, the derating curve reduces permissible dissipation to zero at +155 °C. The upper operating-temperature limit therefore does not imply that the resistor can dissipate its nominal rated power at that temperature.
Precision grades depend on resistance value
The resistance range available with ±2 ppm/°C TCR changes with package size.
| Model | Resistance range with ±2 ppm/°C TCR |
|---|---|
| CRT0402G | 49.9 Ω to 4.99 kΩ |
| CRT0603G | 49.9 Ω to 15 kΩ |
| CRT0805G | 49.9 Ω to 30 kΩ |
| CRT1206G | 49.9 Ω to 49.9 kΩ |
| CRT1210G | 49.9 Ω to 49.9 kΩ |
| CRT2010G | 49.9 Ω to 49.9 kΩ |
| CRT2512G | 49.9 Ω to 49.9 kΩ |
The 01005 package offers ±25 and ±50 ppm/°C grades. The 0201 package extends the selection to ±10 and ±15 ppm/°C grades. Resistance, tolerance and TCR must therefore be selected as a valid combination rather than treated as independent family-wide options.
TCR testing uses +25 °C as the reference temperature, with measurements at −55 °C and +125 °C. These measurement endpoints are distinct from the −55 °C to +155 °C operating-temperature range.
Resistance change under environmental stress
For CRT0402G through CRT2512G, the load-life resistance-change requirement is ±(0.1% + 0.05 Ω), with no visual damage. The test runs for 1,000 hours at 70 ±2 °C, using rated continuous working voltage or maximum working voltage, whichever is lower, with 1.5 hours on and 0.5 hours off.
The same model group has a biased-humidity resistance-change requirement of ±(0.1% + 0.05 Ω), with no visual damage, after 1,000 hours at 85 °C and 85% relative humidity at 10% of operating power. Corresponding resistance-change requirements are ±(0.3% + 0.05 Ω) for CRT0201G and ±(0.5% + 0.05 Ω) for CRT01005G.
These stress-test limits are separate from initial tolerance. The additive resistance term also matters when assessing error at lower resistance values.
Typical applications and application fit
Precision measurement, data acquisition and analog signal-conditioning circuits are target applications. Tolerance down to ±0.01% addresses initial resistance-related error, while the ±2 ppm/°C options address temperature-dependent variation within their available resistance ranges.
Current-sensing circuits are another target application. Selection must account for the chosen resistance value, its initial tolerance, TCR and permissible dissipation together. The family’s overall resistance range starts at 2.49 Ω, making the resistance requirement an important early selection criterion.
Other target applications include automation equipment, printers, navigation equipment, communications, power supplies and non-life-critical medical equipment. Medical use excludes lifesaving, life-critical and life-sustaining applications.
Design-in notes for engineers
- Select the complete resistance, tolerance, TCR and package combination before fixing the bill of materials.
- Assess continuous dissipation against ambient temperature and the power-derating curve.
- Check operating voltage against both the power-derived rated voltage and the package voltage ceiling. Treat the overload rating separately from continuous operation.
- Include initial tolerance, temperature-related variation and stress-related resistance change in the accuracy budget.
- Use the package-specific body dimensions and recommended solder-pad layout when preparing the PCB footprint.
- Keep lead-free assembly within the soldering profile: 260 °C peak package-body temperature, less than 30 seconds within 5 °C of peak, and a maximum of three reflow cycles.
- Validate final selection under the actual operating and assembly conditions.
Further reading
- Resistor Technology Selection and Benchmark Guidelines
- What Is a Resistor? Types, Ratings and Selection
- High-Temperature Applications Resistor Guidelines
Source
This article is based on the Bourns product announcement and official product documentation. Engineers should refer to the current manufacturer datasheet for final design and qualification.
References
- CRT-G Series General-Purpose Precision Thin Film Chip Resistors, Bourns, revision September 2026.
- Bourns Introduces CRT-G Series Precision Thin Film Chip Resistors for Low-Drift Measurement Circuits, Bourns, November 11, 2026.
