Power Resistor M247 - metal film

Thin-film power resistor for high power and switching power stages

The M247 series is a thin-film metal power resistor for applications where high power, compact design and low-inductance behaviour are required. The resistor is built in a TO-247 package with epoxy encapsulation and is suitable for high-power electronics such as inverters, drive and power modules or power supplies.

Depending on the type, 100 W (M247-2) or 140 W (M247-3) @ 25 °C on heatsink are available; without heatsink, 3 W or 5 W are permitted (0 W at +175 °C). Combined with a resistance range from 0.02 Ω to 51 kΩ, M247 can be used both as a low-ohmic current-sense or load resistor and in higher-ohmic branches for current or voltage limiting. Resistance tolerances from ±1% to ±5% cover typical requirements from more precise to classic power applications.

The low-inductance design, with a typical inductance of only about 12 nH, reduces parasitic effects in switching or high-frequency circuits. The temperature coefficient is graded according to resistance value: ±50 ppm/°C for R ≥ 10 Ω, ±100 ppm/°C for 0.1 Ω ≤ R < 10 Ω and ±250 ppm/°C for R < 0.1 Ω. With an operating temperature range from −55 °C to +175 °C and dielectric strength of 2500 VAC, the M247 is suitable for both thermally and electrically demanding operating conditions.

The datasheet specifies extensive tests, including load life, damp heat, thermal shock, resistance to soldering heat, vibration and dielectric strength. The permissible resistance changes remain within a few percent or a small additional absolute value, so M247 supports stable behaviour over lifetime even in continuously operated power and measurement applications.

Options

• Types: M247-2 (100 W) and M247-3 (140 W) @ 25 °C on heatsink, 3 W or 5 W without heatsink
• Resistance range: 0.02 Ω to ≤51 kΩ with freely selectable values (in xxxkxxx format e.g. 10k100)
• Resistance tolerances: ±1% (from 0.1 Ω) and ±5% over the full range
• Temperature coefficients: TK50, TK100, TK250 (±50 / ±100 / ±250 ppm/°C) depending on resistance