USR UNR 4-3425 3825 4020 Powertron * * * * * Resistances from 0.05Ohm to 500Ohms Power Rating to 50Watt Resistance Tolerances to 0.01% TCR to 1ppm/K Load Stability to 0.01% SPECIFICATIONS Type USR 43425 3825 USR 44020 Resistance Range UNR 43425 3825 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 70C for 3825H with heatsink Thermal Resistance Rthj-c Tolerances from 0.05 Ohms from 10.0 Ohms from 50.0 Ohms 3W 5W 30 W 2.5 W 2.5 W 30 W 3W 5W 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 155C) typ. 3ppm/K (-55 to 125C) upon request 1ppm/K (0 to 60C) Voltage Proof 750 VDC max. Current 15 A Thermal EMF < 0.1V/K Operating Temperature Range -55 to 155C Resistor Material Substrate 50 W NiCr-Foil 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 Ordering Information Part Number - Resistance - Contact - Tolerance - TCR USR 4-3825H 10Ohms D 0.5% 3ppm Document Number: 64223 Revision: 20-09-10 For technical questions, contact: powertron@vishaypg.com www.powertron.de 1 USR UNR 4-3425 3825 4020 Powertron SPECIFICATIONS (continued) Temperature Coefficient 1500 1000 +5ppm/K -5ppm/K DR/R (ppm) 500 0 Nominal Spread 2.3ppm/K +4,4 ppm/K -500 Nominal DR/R Nominal Spread 2.3ppm/K -1000 -1500 -50 0 -25 50 25 Temperature (C) 100 75 125 Power (% from nominal power) Derating Power Rating Notes - The U-Series Resistors must be attached to a suitable heatsink. The maximum internal resistor temperature is 155C. To specify an appropriate heatsink use the following formula : 120 100 80 RqH = TMAX - ( P x RqR ) - TA P 60 40 20 Where: 0 25 50 85 100 115 130 145 155 Temperature of the backplate(C) RqH = Thermal Resistance of Heatsink ( K/W ) RqR = Thermal Resistance of Resistor ( K/W ) TMAX = Maximum Temperature of Resistor TA = Ambient Temperature of Heatsink ( C ) P = Power Through Resistor ( W ) Dimensions USR 4-3425 / UNR 4-3425 www.powertron.de 2 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 O3.50 0.1 O0.14 0.004 H O0.8 0.1 O0.031 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 For technical questions, contact: powertron@vishaypg.com Document Number: 64223 Revision: 20-09-10 USR UNR 4-3425 3825 4020 Powertron SPECIFICATIONS (continued) USR 4-3825 / UNR 4-3825 Dimension mm tol. (mm) inches tol. (inches) A 49.00 2.0 1.93 0.079 B 38.00 0.3 1.50 0.012 C 24.00 0.2 0.94 0.008 D 4.00 0.1 0.16 0.004 E 34.00 0.3 1.34 0.012 F 17.50 0.2 0.69 0.008 G 1.5x45 0.1 0.6x45 0.004 H O0.8 0.1 O0.031 0.004 I 27.50 0.2 1.08 0.008 J 17.50 0.2 0.69 0.008 K O3.2 0.1 O0.126 0.004 L 2.00 0.1 0.08 0.004 M 5.50 0.1 0.22 0.004 N 15.00 0.2 0.59 0.008 O 3.00 0.2 0.12 0.008 Dimension mm tol. (mm) inches tol. (inches) A 49.00 2.0 1.93 0.079 B 38.00 0.3 1.50 0.012 C 24.00 0.2 0.94 0.008 D 4.00 0.1 0.16 0.004 E 34.00 0.3 1.34 0.012 F 17.50 0.2 0.69 0.008 G 1.5x45 0.1 0.6x45 0.004 H O0.8 0.1 O0.031 0.004 I 27.50 0.2 1.08 0.008 J 17.50 0.2 0.69 0.008 K O3.2 0.1 O0.126 0.004 L 2.00 0.1 0.08 0.004 M max.10.3 0.2 max.0.4 0.008 N 15.00 0.2 0.59 0.008 O 3.00 0.2 0.12 0.008 P 19.00 0.2 0.75 0.008 Dimension mm tol. (mm) inches tol. (inches) A 45.40 2.0 1.79 0.079 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 O3.80 0.1 O0.15 0.004 H O0.8 0.1 O0.031 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 USR 4-3825H / UNR 4-3825H USR 4-4020 / UNR 4-4020 Document Number: 64223 Revision: 20-09-10 For technical questions, contact: powertron@vishaypg.com www.powertron.de 3 Legal Disclaimer Notice Vishay Precision Group Disclaimer ALL PRODUCTS, PRODUCT SPECIFICATIONS AND DATA ARE SUBJECT TO CHANGE WITHOUT NOTICE. Vishay Precision Group, Inc., its affiliates, agents, and employees, and all persons acting on its or their behalf (collectively, "Vishay Precision Group"), disclaim any and all liability for any errors, inaccuracies or incompleteness contained herein or in any other disclosure relating to any product. The product specifications do not expand or otherwise modify Vishay Precision Group's terms and conditions of purchase, including but not limited to, the warranty expressed therein. Vishay Precision Group makes no warranty, representation or guarantee other than as set forth in the terms and conditions of purchase. To the maximum extent permitted by applicable law, Vishay Precision Group disclaims (i) any and all liability arising out of the application or use of any product, (ii) any and all liability, including without limitation special, consequential or incidental damages, and (iii) any and all implied warranties, including warranties of fitness for particular purpose, non-infringement and merchantability. Information provided in datasheets and/or specifications may vary from actual results in different applications and performance may vary over time. Statements regarding the suitability of products for certain types of applications are based on Vishay Precision Group's knowledge of typical requirements that are often placed on Vishay Precision Group products. It is the customer's responsibility to validate that a particular product with the properties described in the product specification is suitable for use in a particular application. No license, express, implied, or otherwise, to any intellectual property rights is granted by this document, or by any conduct of Vishay Precision Group. The products shown herein are not designed for use in life-saving or life-sustaining applications unless otherwise expressly indicated. Customers using or selling Vishay Precision Group products not expressly indicated for use in such applications do so entirely at their own risk and agree to fully indemnify Vishay Precision Group for any damages arising or resulting from such use or sale. Please contact authorized Vishay Precision Group personnel to obtain written terms and conditions regarding products designed for such applications. Product names and markings noted herein may be trademarks of their respective owners. Document No.: 63999 Revision: 27-Apr-11 www.vishaypg.com 1