VCS1610Z (Kelvin Connection) Vishay Foil Resistors High Precision Foil Surface Mount Current Sensing Chip Resistors with TCR of 0.2 ppm/C, Load Life Stability of 0.015 %, ESD Immunity up to 25 kV and Fast Thermal Stabilization FEATURES Temperature coefficient of resistance (TCR): 0.2 ppm/C typical (- 55 C to + 125 C, + 25 C ref.) (see table 1) Resistance range: 0.3 to 10 Resistance tolerance: to 0.5 % Load life stability: 0.015 % at 70 C, 2000 h at rated power INTRODUCTION Power rating: 0.25 W at + 70 C The Z-foil technology provides a significant reduction of the Vishay Foil resistors are not restricted to standard values resistive components sensitivity to ambient temperature specific as required values can be supplied at no extra variations (TCR) and applied power changes (PCR). cost or delivery (e.g. 0.345 vs. 0.3 ) Designers can now guarantee a high degree of stability and Electrostatic discharge (ESD) at least to 25 kV accuracy in fixed-resistor applications using solutions based Thermal stabilization time < 1 s (nominal value on Vishays Foil Resistors revolutionary Z-foil technology. achieved within 10 ppm of steady state value) Model VCS1610Z is a surface mount chip resistor designed Short time overload < 0.005 % with 4 pads for Kelvin connection. Utilizing Vishays Bulk Non-inductive, non-capacitive design Metal Z-foil as the resistance element, it provides Thermal EMF: 0.05 V/C typical performance capabilities far greater than other resistor technologies can supply in a product of comparable size. Current noise: 0.010 V /V of applied voltage RMS 0.2 ppm/C typical TCR (- 55 C to + 125 C,+ 25 C ref.) (< - 40 dB) removes errors due to temperature gradients. Rise time: 1 ns effectively no ringing Voltage coefficient: < 0.1 ppm/V This small device dissipates heat almost entirely through the pads so surface mount users are encouraged to be generous Non inductive: < 0.08 H with the boards pads and traces. Non hot spot design Our application engineering department is available to Prototype quantities available in just 5 working days advise and to make recommendations. For non-standard or sooner. For more information, please contact technical requirements and special applications, please foil vishaypg.com contact us. (1) FIGURE 1 - POWER DERATING CURVE TABLE 1 -TOLERANCE AND TCR VS. - 55 C + 70 C RESISTANCE VALUE 100 (- 55 C to + 125 C, + 25 Ref.) 75 TYPICAL TCR VALUE AND TOLERANCE 50 ( ) MAX. SPREAD (ppm/C) 25 0R5 to 10R 0.5 %, 1 % 0.2 4.8 0 - 75 - 50 - 25 0 + 25 + 50 + 75 + 100 + 125 + 150 + 175 0R3 to 0R5 0.5 %, 1 % 0.2 9.8 Ambient Temperature (C) Note Note (1) Power rating: 0.25 W at + 70 C Tighter tolerances and higher values are available. Please contact application engineering foil vishaypg.com * TERMINATIONS Tin/lead plated Two options of lead (Pb)-free leads available: Gold plated Tin plated * Pb containing terminations are not RoHS compliant, exemptions may apply Document Number: 63226 For any questions, contact: foil vishaypg.com www.vishayfoilresistors.com Revision: 6-Jul-12 1 Percent of Rated Power VCS1610Z (Kelvin Connection) Vishay Foil Resistors Why use Kelvin connections Should I be concerned about the impact of ESD on my resistor Four-terminal connections or Kelvin connections are Electrostatic Discharge (ESD) is known to produce required in these low ohmic value resistors to measure a catastrophic failures in thin-film and thick-film (cermet) precise voltage drop across the resistive element. The resistors at only 3000 V. On the other hand, the Bulk Metal 4-terminal configuration eliminates the IR-drop error voltage Foil resistor withstands ESD events up to 25 kV because its that would be present in the voltage sense leads if a standard thicker resistance element and greater metallic mass afford two-terminal resistor were used. much higher energy-handling capability than either the much In current sense resistors the contact resistance and the thinner thin-film resistor or the sparse, non-homogeneous terminations resistance may be greater than that of the metallic content of the thick film resistor. resistive element itself so lead connection errors can be significant if only two terminal connections are used. Should I be concerned about stability In order to select the resistor technology most appropriate to Why is the VCS1610Z vital in avoiding Thermal EMF the application, a designer must take into account all normal (parasitic effect) and extraordinary stresses the resistor will experience in the When two dissimilar metals are heated, a parasitic voltage is application. In addition, the designer must consider the cost generated and creates a DC-offset error. This voltage is and reliability impact involved when it becomes necessary to proportional to a temperature difference between either end add costly additional compensating circuitry when of the pair of conductors. This phenomenon is called a inadequate resistors are selected. The stability of Bulk Thermal Electro-motive Force (Thermal EMF), or Metal Foil resistors, together with the advantages already thermocouple effect. Thermal EMF is an important mentioned, as well as the other basic advantages apparent consideration in low ohmic current sensing resistors used in their specifications will not only provide unequalled mostly in DC circuits. The VCS1610Z is the ideal solution to performance in the circuit but will eliminate all the costs minimize the effect of thermal EMF through the use of associated with extra compensation circuitry. appropriate materials between the resistive layer and the With VCS1610Z, only a minimal shift in resistance value will terminations. occur during its entire lifetime. Most of this shift takes place during the first few hundred hours of operation, and virtually no change is noted thereafter. FIGURE 2 - TRIMMING TO VALUES(Conceptual Illustration)* Current Path Before Trimming Current Path After Trimming Trimming Process Removes this Material from Shorting Strip Area Changing Current Path and Increasing Resistance NOTE: Foil shown in black, etched spaces in white * To acquire a precision resistance value, the Bulk Metal Foil chip is trimmed by selectively removing built-in shorting bars. To increase the resistance in known increments, marked areas are cut, producing progressively smaller increases in resistance. This method eliminates the effect of hot spot and assures the long term stability of the Foil chips. www.vishayfoilresistors.com For any questions, contact: foil vishaypg.com Document Number: 63226 2 Revision: 6-Jul-12