Chip Resistor Selection: Resistance Alone Does Not Define the Part
A 48 V monitoring board used a 10 kOhm resistor as a bleeder. The original RC1206FR-0710KL was a 1206, 1% part rated at 250 mW. A proposed RC0603FR-0710KL had the same resistance and tolerance in a 0603 case. At 48 V, however, P = V squared divided by R gives
Full article
A 48 V monitoring board used a 10 kOhm resistor as a bleeder. The original RC1206FR-0710KL was a 1206, 1% part rated at 250 mW. A proposed RC0603FR-0710KL had the same resistance and tolerance in a 0603 case. At 48 V, however, P = V squared divided by R gives about 230 mW. The 0603 part is rated at 100 mW, well below that load.
Resistance tells you what the circuit needs. Package, rated power, temperature coefficient and working voltage determine whether the part can survive there.
The same footprint does not guarantee the same power rating. RC0603FR-0710KL is listed as a 0603, 10 kOhm, 1%, 1/10 W resistor. CRCW060310K0FKEA is also 0603 and 10 kOhm, but its listed rating is 1/8 W. At 80 C in an enclosure, that room-temperature figure is already reduced.
Tolerance is not the whole error budget. A 100 ppm/°C part can shift by roughly 1% over a 100 C change. For a 100 kOhm / 10 kOhm divider using two 1% resistors, the ratio can move by almost 1.8% in the worst case. That may be fine for a coarse supply monitor, but not for every 12-bit ADC input. Lower-TCR parts or a resistor network can help.
Voltage rating also matters in high-value dividers. For current sensing, a general thick-film resistor is usually the wrong starting point because self-heating and drift affect the measurement; use a low-value alloy shunt and verify the thermal design.
Before approving an alternative, give the circuit function, maximum voltage, continuous current, ambient temperature and acceptable error. Browse chip resistors at https://www.szkwic.com/en/c/resistors-chip-resistors.html or send the BOM and operating conditions to https://www.szkwic.com/en/bom.html .
Shenzhen Kewei Technology Co., Ltd. - Room 431, Building 1, Huafa Compound, 101 Zhenxing Road, Huaqiangbei, Futian District, Shenzhen
Phone / WeChat: +86 191 2521 1182 Email: 19125211182@163.com QQ: 550826937 / 949592795
Kewei's take: what this means for procurement
Industry-level changes end up in individual purchasing decisions: lead time, price, alternatives. Following them regularly beats firefighting.
Related parts in stock
All Parts
All part numbers above are in stock or in transit. Order directly, or submit a BOM and we will match and quote it.
Authentic parts · Same-day shipping · Prototype and volume quantities