Accutrim 1280G, 1285G Vishay Foil Resistors Bulk Metal Foil Technology Ultra High Precision 3 Trimming Potentiometers / Rectilinear, 5 ppm/C and 4 15 ppm/C TCR with a Smooth and Unidirectional Output FEATURES Temperature coefficient of resistance (TCR): (- 55 C to + 125 C ref. at + 25 C) - 15 ppm/C (model 1280G) 3) - 5 ppm/C (model 1285G) - through the wiper 50 ppm/C INTRODUCTION A smooth and unidirectional resistance with leadscrew adjustment Vishay Foil precision trimmers have the Bulk Metal Foil Load life stability: 0.5 % maximum R under full rated resistive element which possesses a unique inherent power at + 25 C for 2000 h temperature and load life stability. Plus, their advanced virtually back lash-free adjustment mechanism makes them Electrostatic discharge (ESD) up to 25 000 V easy to set quickly and accurately and keeps the setting Settability: 0.05 % typical 0.1 % maximum exactly on target. Setting stability: 0.1 % typical 0.5 % maximum, SS Power rating: 0.75 W at + 25 C Resistance range: 10 to 20 k BULK METAL Resistance tolerance: 10 %, 5 % WIREWOUND FOIL Backlash: < 0.05 % Tap test: 0.05 % typical 0.1 % maximum Wiper Travel Wiper Travel O-ring prevents ingress of fluids during any board cleaning operation Terminal finish: gold plated (tin/lead finish available on request) CERMET Wiper Travel TABLE 1 - 1280G AND 1285G SERIES ELECTRICAL SPECIFICATIONS (1) Resistance Tolerance Model 1280G 10 % , Model 1285G 5 % Resistance Range 10 to 20 k TCR Model 1280G 15 ppm/C (- 55 C to + 125 C, ref. + 25 C) (3) TCR Model 1285G 5 ppm/C (- 55 C to + 125 C, ref. + 25 C) Power 0.75 W at + 25 C derated linearly to 0 W at + 125 C (see Fig. 2) Settability 0.05 % typical 0.1 % maximum Setting Stability 0.1 % typical 0.5 % maximum Roll-on, Roll-off 0.25 % typical 1.0 % maximum Load Life Stability 0.5 % R after 2000 h under full rated power at + 25 C End Resistance 2 maximum (2) C.R.V. (noise) 3 typical 10 maximum Frequency Characteristics 10 ns rise time at 1 k to 100 MHz Notes (1) 5 % available on special order (2) The 1280G can be screened for low noise, if required (3) For model 1285G 10 and 20 TCR is 10 ppm/C (4) Panel mount available on special order TABLE 2 - STANDARD VALUE 10 , 20 , 50 , 100 , 200 , 500 , 1 k, 2 k, 5 k, 10 k, 20 k Document Number: 63056 For any questions, contact: foil vishaypg.com www.foilresistors.com Revision: 25-Mar-10 1 Resistance Resistance ResistanceAccutrim 1280G, 1285G Vishay Foil Resistors TABLE 3 - 1280G AND 1285G SERIES MECHANICAL SPECIFICATIONS Adjustment Turns 26 2 turns Backlash < 0.05 % Stops clutch, wiper idles Sealed + 85 C water immersion Torque 5 oz. in. maximum Weight 1.5 grams maximum Construction Case Material Valox Lead Screw Brass Wiper Precious metal brush Rider Block Nylon Element Bulk Metal Foil Lead Material Gold plated phosphor bronze FIGURE 1 - 1280G/1285G SCHEMATIC AND DIMENSIONS in Inches (Millimeters) 0.060 0.190 (1.52 mm) A (4.83 mm) B 0.750 (19.05 mm) C 0.110 0.030 (2.79 mm) A (0.76 mm) A 0.270 (6.86 mm) B 0.190 (4.83 mm) B 0.010 1 23 (0.25 mm) A 0.200 0.050 0.010 (5.08 mm) B (1.27 mm) A (0.25 mm) A 0.039 (0.99 mm) A 0.200 0.100 0.020 (0.51 mm) A (5.08 mm) A (2.54 mm) B 0.125 (3.18 mm) B 0.500 (12.70 mm) A 1 3 CW 2 0.030 (0.76 mm) A TOLERANCES: A = 0.005 (0.13 mm) B = 0.010 (0.25 mm) C = 0.015 (0.38 mm) FIGURE 2 - POWER DERATING CURVE - 55 C + 25 C + 100 + 75 + 50 + 25 0 - 75 - 50 - 25 0 + 25 + 50 + 75 + 100 + 125 + 150 Ambient Temperature (C) www.foilresistors.com For any questions, contact: foil vishaypg.com Document Number: 63056 2 Revision: 25-Mar-10 rcent of Rated ower Pe P