USR UNR 4-3425 4020 Precision Shunt Resistors • • • • • • Resistances from 0.05Ohm to 500Ohms Power Rating to 50Watt Resistance Tolerances to ±0.01% TCR to ±1ppm/K Load Stability to 0.01% Backplate Isolated from Leads SPECIFICATIONS Type USR 43425 USR 44020 Resistance Range UNR 43425 UNR 44020 0.05 to 500 Ohms 0.05 to 400 Ohms other resistance values upon request / power rating depending on resistance value Power rating free air 70°C with heatsink Thermal Resistance Rthj-c Tolerances from 0.05 Ohms from 10.0 Ohms from 50.0 Ohms 3 W (2 W)* 30 W (10 W)* 2.5 W 30 W 3 W (5 W)* 50 W (10 W)* 2.5 W 50 W 3.5 K/W 3.6 K/W 2.1 K/W 2.2 K/W 0.1% / 0.25% / 0.5% / 1% 0.05% / 0.1% / 0.25% / 0.5% / 1% 0.01% / 0.02% / 0.05% / 0.1% / 0.25% / 0.5% / 1% Stability 0.01% Shelf Life Stability 25ppm / ∆R after 1 year 50ppm / ∆R after 3 year Temperature Coefficient max. ±5ppm/K (-55 to 155°C) typ. ±3ppm/K (-55 to 125°C) upon request ±1ppm/K (0°C to 60°C) Voltage Proof 750 VDC max. Current 15 A Thermal EMF < 0.1µV/K Operating Temperature Range -55 to 155°C Resistor Material NiCr-Foil Substrate Al2O3 Housing AlN Epoxy + Al-heatsink Connector Material Cu tinned Terminals 4 Max. Torque 1.0 Nm Notes Specially designed for applications with fast changing electrical load * Under 0.1 Ohm Power Rating Ordering Information Part Description: Part Type - Resistance - Contact - Tolerance - TCR Example: USR 4-3425 10 Ohm D 0.5% 3ppm Riedon Inc. 09/15 300 Cypress Avenue Alhambra CA 91801 www.riedon.com (626) 284-9901 (626) 284-1704 USR UNR 4-3425 3825 3825H 4020 Precision Shunt Resistors SPECIFICATIONS (continued) Temperature Coefficient 800 ∆R/R (ppm) 600 +5ppm/K -5ppm/K 400 200 Nominal Spread ±2.3ppm/K 0 -200 Nominal ∆R/R -400 Nominal Spread ±2.3ppm/K -600 -800 -50 0 -25 25 50 75 100 125 Temperature (°C) Derating Power (% from nominal power) Power Rating Notes The U-Series Resistors must be attached to a suitable heatsink. The maximum internal resistor temperature is 155°C. To specify an appropriate heatsink use the following formula : 120 100 80 40 RθH = TMAX - ( P x RθR ) - TA P 20 Where: 60 0 25 50 85 100 115 130 145 155 Temperature of the backplate(°C) Riedon Inc. 09/15 300 Cypress Avenue Alhambra CA 91801 www.riedon.com RθH = Thermal Resistance of Heatsink ( K/W ) RθR = Thermal Resistance of Resistor ( K/W ) TMAX = Maximum Temperature of Resistor TA = Ambient Temperature of Heatsink ( °C ) P = Power Through Resistor ( W ) (626) 284-9901 (626) 284-1704 USR UNR 4-3425 4020 Precision Shunt Resistors SPECIFICATIONS (continued) Dimensions USR 4-3425 / UNR 4-3425 Dimension mm tol. (±mm) inches tol. (±inches) A 50.00 2.0 1.97 0.079 B 34.00 0.3 1.34 0.012 C 25.00 0.2 0.98 0.008 D 10.00 0.2 0.39 0.008 E 5.00 0.1 0.20 0.004 F 17.80 0.2 0.70 0.008 G Ø3.50 0.1 Ø0.14 0.004 H Ø0.8 0.1 Ø0.031 0.004 I 27.50 0.2 1.08 0.008 J 17.50 0.2 0.69 0.008 K 2.00 0.1 0.08 0.004 L 5.50 0.1 0.22 0.004 M 3.00 0.2 0.12 0.008 USR 4-4020 / UNR 4-4020 Riedon Inc. 09/15 300 Cypress Avenue Alhambra CA 91801 www.riedon.com Dimension mm tol. (±mm) inches tol. (±inches) 0.079 A 45.40 2.0 1.79 B 40.00 0.3 1.57 0.012 C 20.00 0.2 0.79 0.008 D 10.00 0.2 0.39 0.008 E 30.00 0.2 1.18 0.008 F 20.00 0.2 0.79 0.008 G Ø3.80 0.1 Ø0.15 0.004 H Ø0.8 0.1 Ø0.031 0.004 I 5.08 0.1 0.20 0.004 J 15.24 0.2 0.60 0.008 K 3.00 0.1 0.12 0.004 L 7.00 0.1 0.28 0.004 M 4.00 0.1 0.16 0.004 (626) 284-9901 (626) 284-1704