Z Series (Z-Foil) Vishay Foil Resistors Ultra High Precision Z-Foil Though-Hole Resistor with TCR of 0.05 ppm/C, Tolerance of 0.005 % (50 ppm), Load Life Stability of 0.005 % FEATURES Temperature coefficient of resistance (TCR): - 0.05 ppm/C nominal (0 C to + 60 C) - 0.2 ppm/C nominal (- 55 C to + 125 C, + 25 C ref.) (see table 1) Rated power: to 1 W at + 125 C (see table 2) Resistance tolerance: to 0.005 % (50 ppm) INTRODUCTION Load life stability: 0.005 % at 70 C, 2000 h or 0.015% at 70C,10000 h (see table 4) The Bulk Metal Foil resistor is based on a special thermo-metalic stress concept wherein a proprietary bulk Resistance range: 5 to 600 k metal cold rolled foil is cemented to a ceramic substrate. It is Vishay Foil Resistors are not restricted to standard values then photoetched into a resistive pattern. Then it is laser specific as required values can be supplied at no extra adjusted to any desired value and tolerance. Because the cost or delivery (e.g. 1K2345 vs. 1K) metals used are not drawn, wound or mistreated in any way Total accumulated change in resistance over life (EOL) during manufacturing process, the Bulk Metal Foil resistor or Total Error Budget < 0.1 % (or better with PMO)** maintains all its design, physical and electrical characteristics while winding of wire or sputtering does not. Electrostatic discharge up to 25 000 V Z foil resistors achieve maximum stability and near-zero Non-inductive, non-capacitive design TCR. These performance characteristics are built-in for Rise time: 1 ns effectively no ringing every unit, and do not rely on screening or other artificial Current noise: 0.010 V /V of applied voltage (< - 40 RMS means for uniform performance. dB) The stability of a resistor depends primarily on its history of Thermal EMF: 0.05 V/C typical exposures to temperature. Stability is affected by: Voltage coefficient: < 0.1 ppm/V 1. Reversible changes in the ambient temperature and heat Low inductance: < 0.08 H typical from adjacent components (defined by the Temperature Coefficient of Resistance, or TCR) Thermal stabilization time < 1 s (to reach within 10 ppm of steady state value) 2. Short-term steady-state self-heating (defined by Power TCR or PCR) Pattern design minimizing hot spots 3. Irreversible destabilizing shock of suddenly-applied Terminal finish: lead (Pb)-free or tin/lead alloy power Matched sets are available per request 4. Long-term exposure to applied power (load-life stability) (TCR tracking: to 0.5 ppm/C) 5. Repetitive stresses from being switched on and off Prototype quantities available in just 5 working days In very high-precision resistors, these effects must be taken or sooner. For more information, please contact into account to achieve high stability with changes in load foil vishaypg.com (Joule Effect) and ambient temperature. TABLE 1 - NOMINAL TCR AND MAX. SPREAD Vishay Foil Resistors new Z-Foil technology provides an (- 55 C to + 125 C, + 25 C ref.) order of magnitude reduction in the Bulk Metal Foil elements sensitivity to temperature changes - both external NOMINAL TCR AND STANDARD VALUE MAX. SPREAD and internal. This technology provides TCR of TOLERANCE (ppm/C) 0.05 ppm/C nominal (instrument range: 0 C to +60 C), 100 to 600 K 0.005 % 0.2 0.6 0.2 ppm/C nominal (military range: - 55 C to + 125 C, 80 to < 100 0.005 % 0.2 0.8 + 25 C ref), and a PCR of 5 ppm at rated power. 50 to < 80 0.01 % 0.2 1.0 In order to take full advantage of this TCR improvement, it is 25 to < 50 0.01 % 0.2 1.3 10 to < 25 0.02 % 0.2 1.6 necessary to take into account the differences in the 5 to < 10 0.05 % 0.2 2.3 resistors response to each of the above-mentioned effects. The Z series has been developed to successfully deal with these factors. * Pb containing terminations are not RoHS compliant, exemptions may apply ** See PMO page 5 Document Number: 63187 For any questions, contact: foil vishaypg.com www.vishayfoilresistors.com Revision: 22-Oct-13 1Z Series (Z-Foil) Vishay Foil Resistors FIGURE 1 - NOMINAL RESISTANCE/ FIGURE 2 - POWER DERATING CURVE TEMPERATURE CURVE - 55 C + 70 C (for more details, see table 1) 100 Rated Power +250 +250 75 +200 +200 +150 +150 +100 +100 50 +50 +50 R R 0 0 (ppm) -50 0.05 ppm/C -50 25 -100 -100 - 0.1 ppm/C 0.1 ppm/C -150 -150 0.14 ppm/C 0 -200 -200 - 75 - 50 - 25 0 + 25 + 50 + 75 + 100 + 125 + 150 + 175 + 200 - 0.16 ppm/C 0.2 ppm/C -250 -250 Ambient Temperature (C) -55 -25 0 +25 +65 +75 +100 +125 Note The TCR values for < 100 are influenced by the termination composition and result in deviation from this curve FIGURE 3 - TRIMMING TO VALUES (conceptual illustration) Interloop Capacitance Current Path Reduction Before Trimming Note in Series To acquire a precision resistance value, the Bulk Metal Foil chip is trimmed by selectively removing built-in shorting bars. Current Path After Trimming Mutual Inductance To increase the resistance in known increments, Reduction due marked areas are cut, producing progressively Trimming Process to Change in smaller increases in resistance. This method Removes this Material Current Direction reduces the effect of hot spots and improves from Shorting Strip Area the long-term stability of the Vishay Foil resistor. Changing Current Path and Increasing Resistance Foil shown in black, etched spaces in white FIGURE 4 - THROUGH-HOLE STYLE (>29 YEARS) 40 20 0 -20 -40 -60 -80 -100 -120 0 5 10 15 20 25 30 Time (Years) www.vishayfoilresistors.com For any questions, contact: foil vishaypg.com Document Number: 63187 2 Revision: 22-Oct-13 R/R (ppm) Rated Power (%) at + 70