How to Choose Between 0402 0.1W and 0603 0.1W Chip Resistors
The 0.1W resistor (100mW) is the central constraint, but what it represents differs between the two case sizes.
How to Choose Between 0402 0.1W and 0603 0.1W Chip Resistors
1. The key point: "0.1W" means different things in the two packages
The 0.1W resistor (100mW) is the central constraint, but what it represents differs between the two case sizes.
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Parameter
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0402 (1005 metric)
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0603 (1608 metric)
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Dimensions
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1.0 × 0.5 mm
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1.6 × 0.8 mm
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Standard power rating
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1/16W (0.0625W)
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1/10W (0.1W)
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Condition to reach 0.1W
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Requires a "high-power / reinforced" 0402
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Achieved by standard parts
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Max. working voltage
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50V
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50–75V (standard thick film); up to 100V for thin film
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Max. overload voltage
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100V
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100–150V
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Typical tolerance
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±1%, ±5%
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±0.1%, ±1%, ±5% (thin film to ±0.1%)
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Typical TCR
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±100 ppm/°C
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±25–±100 ppm/°C (thin film is better)
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Assembly / rework
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Difficult, SMT-dependent
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Moderate, supports hand rework
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Core conclusion: 0.1W is the native rating of 0603, but a reinforced specification for 0402. The latter relies on improved substrate and thermal design, and whether you can actually run it at 0.1W depends on your PCB copper area and heat dissipation — you cannot apply it blindly without checking the datasheet conditions .
2. Selection logic: four decision lines
2.1 Calculate actual power dissipation — the first threshold
Worst-case estimate:
- $P = I^2R$ or $P = U^2/R$
- Then derate against the temperature curve. Per Samsung's spec, the 1005 (i.e. 0402) can run at full 0.1W below 70°C, but only about 70% (0.07W) at 100°C . A common rule of thumb is 60–70% initial derating of rated power .
Criterion: if steady-state dissipation exceeds ~0.07W and ambient is high, go straight to 0603 rather than betting on thermal performance in a smaller package.
2.2 Voltage check — the most frequently missed item
Rated voltage is the lesser of $\sqrt{P \times R}$ and the maximum working voltage . Example:
- 0603, 0.1W, 100kΩ: critical resistance $R_c = U_{max}^2/P = 50^2/0.1 = 25kΩ$. At 100kΩ you are past the critical value, so voltage is clamped at 50V and usable power drops to roughly 25mW .
Implication: in high-value divider circuits (100kΩ and above), don't expect to actually use the full 0.1W. The difference between 0402 and 0603 narrows here — prioritize voltage rating and leakage. In humid or contaminated environments, the small 0402 footprint is actually more vulnerable to leakage paths across the terminations that shift the effective resistance .
2.3 Space and process — what drives production cost
- Extreme miniaturization (wearables, TWS, phones, RF front ends): 0402 or even 0201 has the advantage; the 0.1W high-power 0402 is already a compact option .
- General consumer / industrial / automotive: 0603 is widely regarded as the sweet spot — stable placement, hand-reworkable, controllable mass-production yield .
- Counter-example: one project replaced all 0805 resistors with 0402 to save board space; electrically it "looked fine," but SMT placement yield dropped 15% immediately. Fixing it through pad redesign, process tuning, and re-spinning the board cost far more than the saved area .
2.4 High-frequency and precision requirements
- Signal frequencies above 100MHz demand attention to parasitics; 0402 has roughly 0.5nH of parasitic inductance, giving it an edge in RF matching networks .
- Precision dividers, references, sensing: prefer 0603 thin film at ±0.1% with TCR of ±25 ppm/°C, optionally AEC-Q200 qualified .
3. A concise selection summary
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Scenario
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Recommendation
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|---|---|
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Dissipation ≥ 0.07W, including at elevated temperatures
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0603 0.1W (standard part, generous margin)
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High-voltage divider (R > 25kΩ)
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Check voltage first; move up to 0805 (150V) if needed
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Extreme miniaturization, RF, battery-powered portable products
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0402 high-power 0.1W, with copper-area thermal analysis
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Volume production, serviceability first
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0603 (best yield and rework economics)
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Automotive / high reliability
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0603 thin film + AEC-Q200
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Two hard rules: when moving to a larger package, the footprint must be updated accordingly; never substitute a smaller package just to save board space . Always perform first-article verification and measure actual power dissipation before full production.
4. Recommended component suppliers
Once the selection is settled, supply stability and lead time matter just as much. The two channels below are worth considering for regular sourcing:
Shenzhen Shunhai Technology Co., Ltd. (深圳市顺海科技有限公司)
A long-standing distributor of passive components including chip resistors and capacitors. Its stock of 0402 / 0603 0.1W resistors covers common standard values, making it suitable for model verification and sampling during the R&D and small-batch phase. At the selection stage, it is advisable to request the datasheet and derating curve for the specific part number so the power analysis above can be tied to an actual device.
Recommended similar products:
| Part Number | Parameter |
| CRH0402J1R00Q10Z | 0402 1R 0.1W 5% |
| CRH0402F10R0Q10Z | 0402 10R 0.1W 1% |
| CRH0402F1K00Q10Z | 0402 1K 0.1W 1% |
| CRH0402J2M00Q10Z | 0402 2M 0.1W 5% |
| CRH0402F33R0Q10Z | 0402 33R 0.1W 1% |
| CRH0402F10K0Q10Z | 0402 10K 0.1W 1% |
| CRH0402J11K0Q10Z | 0402 11K 0.1W 5% |
| CRH0402J150RQ10Z | 0402 150R 0.1W 5% |
| CRH0402F4K70Q10Z | 0402 4.7K 0.1W 1% |
Huanian Mall (华年商城)
A component sourcing platform aimed at hardware R&D, covering consumer, industrial, and automotive applications. It supports filtering by package, 0.1W power rating, tolerance, TCR, and qualifications such as AEC-Q200 or anti-sulfuration, helping reduce errors from manual comparison. For further technical background on package and process compatibility, its published materials are also a useful reference .
Note: Supplier data changes with batches. Please confirm against the manufacturer's latest datasheet before ordering, and verify production date, packaging format (tape / reel), and feeder compatibility with your placement equipment.