Vishay SFernice RTO 50 User Guide
Summary
Discover the RTO 50 Vishay Sfernice, a reliable thick film power resistor in a TO-220 package designed for high-power dissipation (up to 50W). This component offers superior heat management and adjustable ohmic values via sand trimming for enhanced stability. The manual provides comprehensive technical specifications, including mechanical dimensions, electrical performance testing standards (EN/MIL), detailed thermal calculations, and guidelines necessary for system designers and electrical engineers integrating high-current components into demanding applications.
Page 1 Text Content
RTO 50 Vishay Sfernice
50 W Power Resistor, Thick Film Technology, TO-220
FEATURE 50 W at 25 °C heatsink mounted Adjusted by sand trimming Leaded or surface mount versions High power to size ratio Non inductive element Compliant to Ro HS directive 2002/95/EC
Because of the knowledge and experience in Thick Film technology, Vishay Sfernice has been able to develop a high power resistor in a TO-220 package called RTO 50. The special design of this component allows the dissipation of 50 W when mounted on a heatsink. The ohmic value is adjusted by sand trimming. This process does not generate hot spots as in laser trimming, which could lead to microcracks on each side of the curve. This process improves the reliability and the stability of the resistor and at the same time gives a good overload capability.
DIMENSIONS in millimeters
RTO 50F - LEADED
RTO 50C - FOR SURFACE MOUNTING
Only for RTO 50 version C = during surface mount soldering, the soldering temperature profile must not cause the metal tab of this device to exceed 220 °C.
MECHANICAL SPECIFICATIONS
ELECTRICAL SPECIFICATIONS
Mechanical Protection Molded
Resistance Range 0.010 Ω to 550 kΩ serie E24
Resistive Element Thick Film
Connections Tinned copper alloy Tolerances Standard ± 1 % to ± 10 %
Weight 2.2 g max. Dissipation and Associated Onto a heatsink
50 W at + 25 °C
DIMENSIONS Thermal Resistance RTH (j - c): 2.6 °C/W
Standard Package TO-220 and Nominal Power free air:
Insulated Case 2.25 W at + 25 °C
Temperature Coefficient See Performance table ENVIRONMENTAL SPECIFICATIONS Standard (- 55 °C; + 150 °C) ± 150 ppm/°C
Temperature Range - 55 °C to + 155 °C Limiting Element Voltage UL 300 V Climatic Category 55/155/156
Dielectric Strength 2000 VRMS - 1 Min
Sealing Sealed container MIL STD 202 (301) 10 m A max.
Solder immersion
Insulation Resistance ≥ 106 MΩ
Flammability IEC 60695-11-5
Inductance ≤ 0.1 µH
2 applications 30 s
Critical Resistance 1.8 kΩ
seperated by 60 s
Not compatible with Ro HS reflow profile.
Document Number: 50035 For technical questions, contact: [email protected] www.vishay.com
Revision: 18-May-09
Page Summary Contents For Vishay SFernice RTO 50 User Guide
Manual Details
| Brand | Vishay |
|---|---|
| Pages | 4 |
| File Size | 109.42 KB |
| Published | May 28, 2026 |
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Frequently Asked Questions
What is the maximum power a user can dissipate with this resistor?
The RTO 50 component allows for the dissipation of up to 50 W when mounted on a heatsink.
How must I choose a heatsink for optimal performance?
Users must calculate their needs using formula (1) and ensure the maximum working temperature does not exceed 155 °C.
Does sand trimming affect resistor reliability?
No, sand trimming does not generate hot spots like laser trimming, which improves reliability and stability.
What are the environmental operating temperature limits?
The standard operating temperature range is -55 °C to +155 °C.