FRSM Series of Precision Chip Resistors Vishay Foil Resistors Z-1 Foil Ultra High Precision Wrap-around Chip Resistor for Improved Load Life Stability of 0.0025% (25 ppm) with TCR of 0.05 ppm/C and withstands ESD of 25 KV min FEATURES Temperature coefficient of resistance (TCR): 0.05 ppm/C typical (0 C to + 60 C) 0.2 ppm/C typical (- 55 C to + 125 C, + 25 C ref.) Resistance tolerance: to 0.01 % Power coefficient R due to self heating: 5 ppm at rated power Power rating: to 750 mW at + 70 C Load life stability: Top View 0.0025 % at 70 C, 2000 h at rated power. 0.005 % at 70 C, 10,000 h at rated power. Resistance Range: 5 to 125 k(for higher and lower INTRODUCTION values, please contact us) The FRSM is based on the new generation Z1- technology of Vishay Foil resistors are not restricted to standard values the Bulk Metal Precision Foil resistor elements by Vishay we can supply specific as required values at no extra cost or delivery (e.g. 1K2345 vs. 1K) Precision Group (VPG), which makes these resistors Thermal stabilization time < 1 s (nominal value achieved virtually insensitive to destabilizing factors. Their element, within 10 ppm of steady state value) based on the new Z-1 Foil is a solid alloy that displays the Electrostatic discharge (ESD) at least to 25kV desirable bulk properties of its parent material thus, it is Short time overload: 0.005 % inherently stable (remarkably improved load life stability of Rise time: 1 ns effectively no ringing 25 ppm), noise-free and withstands ESD to 25KV or more. The alloy is matched to the substrate and forms a single Current noise: 0.010 V /V of applied voltage RMS entity with balanced temperature characteristics for an (< - 40 dB) unusually low and predictable TCR over a wide range from Voltage coefficient: 0.1 ppm/V -55 C to more than 175C. Resistance patterns are Non inductive: 0.08 H photo-etched to permit trimming of resistance values to very Non hot spot design tight tolerances. (1) Terminal finishes available: lead (Pb)-free, tin/lead alloy Matched sets are available on request Our application engineering department is available to Prototype quantities available in just 5 working days advise and make recommendations. For non-standard or sooner. For more information, please contact technical requirements and special applications, please foil vishaypg.com contact us using the e-mail address in the footer below. For higher temperature application up to +240 C and for better performances, please contact us FIGURE 1 - POWER DERATING CURVE TABLE 1 - TOLERANCE AND TCR VS. - 55 C + 70 C (1) 100 RESISTANCE VALUE (- 55 C to + 125 C, + 25 C Ref.) 75 RESISTANCE TYPICAL TCR AND TOLERANCE 50 VALUE MAX. SPREAD (%) () (ppm/C) 25 250 to 125K 0.01 0.2 1.8 0 100 to < 250 0.02 0.2 1.8 - 75 - 50 - 25 0 + 25 + 50 + 75 + 100 + 125 + 150 + 175 50 to < 100 0.05 0.2 2.8 Ambient Temperature (C) 25 to < 50 0.1 0.2 3.8 10 to < 25 0.25 0.2 3.8 Lead (Pb)-free terminals Tin/lead alloy terminals 5to < 10 0.5 0.2 7.8 (1) Pb containing terminations are not RoHS compliant, exemptions may apply. Document Number: 63209 For any questions, contact: foil vishaypg.com www.vishayfoilresistors.com Revision: 8-Nov-12 1 Rated Power (%)FRSM Series of Precision Chip Resistors Vishay Foil Resistors While other resistor technologies can take several seconds or even ABOUT THE FRSM minutes to achieve a steady state thermal stabilization (thermal lag), Several factors need to be considered when choosing a resistor for Vishay Foil resistors feature an almost instantaneous thermal applications that require long term stability, including TCR (ambient stabilization time and a nearly immeasurable 1 ns rise time temperature), Power TCR (self heating), load-life stability for more effectively with no ringing. The stress levels of each application are than 10K hours (instead of the typical 1000 or 2000 hours load-life), different so the designer must make an estimation of what they might end-of-life tolerance (which is more important than the initial be and assign a stress factor to each one. The stress may normally tolerance), thermal EMF (low values, D.C), thermal stabilization and be low but for these purposes, we must assure that the installed ESD. Some precision resistor technologies such as Precision Thin precision resistor is capable of reliability withstanding all potential Film offer designers tight initial tolerances as low as 0.02 % but have stresses. For example, if the resistor is installed in a piece of poor load life stability, high end-of-life tolerance, long thermal equipment that is expected to go out into an oil field in the back of a stabilization, high drifts during operational life and ESD sensitivity. pickup truck, shock and vibration and heat from the sun are obvious Other resistor technologies, such as Wirewounds, provide low factors. The specific causes of resistor drift are listed in Table 4 and absolute TCR and excellent current noise of -40 dB but have high the allowances shown are for full scale exposure. The designer may inductance and poor rise time (or thermal lag) for more than a few choose to use a percentage of full scale stress factor if the seconds. equipment will never see the full scale conditions. For example, a laboratory instrument that is expected to be permanently installed in There are essentially only three resistance technologies widely used an air-conditioned laboratory does not need an end-of-life allowance for precision resistors in military and space applications: Thin Film, for excessive heat. There are other reasons for tolerancing the Wirewound and Bulk Metal Foil. Each has its own balance of resistors tighter than the initial calculation: Measurement equipment characteristics and costs that justify its selection in these accuracy is traditionally ten times better than the expected accuracy applications. Thin Films are most cost-efficient within their normal of the devices under test. So, these tighter tolerance applications range of characteristics but have the highest TCR, highest noise and require a Foil resistor. Also, the drift of the resistor without any have the least stability of the three technologies. Wirewounds have stress factor considerations results in a shift over time that must be low noise, low TCR and a high level of stability at moderate cost but considered. FRSMs have the least amount of time shift. The also have high impedance and slow signal response. Wirewounds manufacturers recommended recalibration cycle is a factor in the can also have a higher power density, but some stability is lost saleability of the product and the longer the cycle, the more through temperature cycling and load-life when made in smaller acceptable the product. Foil resistors contribute significantly to the configurations. Bulk Metal Foil resistors have the lowest noise, longer calibration cycle. lowest TCR, highest stability and highest speed of any technology but may have a higher cost, depending upon model. With Bulk Metal Foil resistors, savvy designers often save overall by concentrating the circuit stability in the foil resistors where FIGURE 2 - TRIMMING TO VALUES* exceptional stability allows for use of less-costly active devices---an (Conceptual Illustration) option not available with other resistor technologies because foil requires a smaller total error budget through all cumulative resistor life exposures. Also, foil often eliminates extra circuitry added merely for the purpose of correcting the limitations of other resistor components. FRSMs Bulk Metal Foil resistors, based on new Current Path Interloop Capacitance generation technology and improved production methods starting Before Trimming Reduction in Series from February 2011, offer designers the complete set of top performance characteristics to simplify circuitry and lower overall Current Path After Trimming system costs by reducing the number of required parts while Mutual Inductance Trimming Process Reduction due assuring a better end product. The new series of FRSM feature a Removes this Material to Change in from Shorting Strip Area long-term load-life stability within 0.0025 % after 2000 hours and Current Direction Changing Current Path 0.005% after 10000 hours under full rated power at + 70 C, first time and Increasing Resistance in the history of all resistor technologies. In addition to their low absolute TCR of almost zero TCR , the devices offer Power TCR (R due to self heating) to 5 ppm at rated power tight tolerance Note: Foil shown in black, etched spaces in white from 0.01% and thermal EMF of 0.05 V/C. Current design practice has been to over specify resistors to allow for expected tolerance degradation during service and there is a trend to move to * To acquire a precision resistance value, the Bulk Metal Foil chip commercial off the shelf (COTS) parts instead of MIL spec Qualified is trimmed by selectively removing built-in shorting bars. To (QPL) parts. Vishay Precision Group offers a new approach with increase the resistance in known increments, marked areas are cut, lower prices to bring Foil resistors within the reach of designers producing progressively smaller increases in resistance. This whose end-of-life tolerance target is 0.05 % (total end of life method eliminates hot spot and improves the long term stability of cumulative deviation from nominal) or less with COTS resistors the resistor. having all the inherent features for long term reliability. www.vishayfoilresistors.com For any questions, contact: foil vishaypg.com Document Number: 63209 2 Revision: 8-Nov-12